Burners 101

[Mikey98118]

Ways? What are ways? the depressions that the three jaws slide up and down in.

[Mikey98118]

Metal removal isn't only about tool speed

Metal removal is about surface speed and what abrasive is doing the sanding or grinding. Sanding and grinding products all have maximum speed limits. Sanding sticks, cones, and paper that you place on shank split mandrels, and  barrel sanding mandrels all have maximum speeds of 10,000 RPM or less; not a good fit in a rotary tool.

But one man's problem is another man's solution. If you only have a drill to work with, these sanding products are your meat and potatoes.

On the other hand, what the sandpaper's abrasive is, becomes much more important than in a grinding wheel; there are faster cutting abrasives than aluminum oxide, and a cloth backing is better than paper.

[Mikey98118]

Enlarging diameters of capillary tube and MIG contact tip orifices

Actual inside diameters vary in both products. Micro drill bits are handy as go/no go gauges, and for reaming tubing and MIG tips. Gauge drill bits come as close as anything else you’ll find for judging orifice sizes; they come in very economical tungsten carbide bit sets, which can be run in rotary tools, (and more importantly) in pin vice drills.

    The wire files in torch tip cleaner kits come in similar gauge sizes; typically, between #77-76 and #51-49. But, the reason for double numbers is that they are wire files; the smaller gauge size is how small a hole each file can be pushed into. The larger gauge size is the how far it can enlarge the hole, by being worked back; giving a short range of enlargement. Torch tip cleaner kits work very nicely together with gauge number drill bits, to adjust hole sizes in copper MIG tips perfectly for capillary tubes; also, for producing pretty exact orifice sizes in brass and copper capillary tube. Wire files are ineffective for enlarging orifice sizes in stainless steel capillary tube, but are very effective at deburring it.

 

Drill gauge    Metric equivalent    Thousandths

    #80                     .350mm                   0.014”

    #78                     .400mm                   0.016”

    #76                     .500mm                   0.020”

    #73                     .600mm                   0.024”

    #72                     .635mm                   0.025”

    #71                     .650mm                   0.026”

    #70                     .700mm                   0.028”

    #69                     .750mm                   0.029”

    #68                     .800mm                   0.031”    

    #66                     .850mm                   0.0335”

    #65                     .900mm                   0.035”

    #64                     .914mm                   0.036”

    #63                     .950mm                   0.037”

    #62                     .965mm                   0.038”

    #61                     1.00mm                   0.039”

    #51                     1.70mm                   0.067”

    #50                     1.75mm                   0.070”

    #49                     1.85mm                   0,073’’

 

Diamond reamer sets are meant for working on glass beads, but are good for reaming MIG tip orifices a little larger to accept capillary tubes. They are also a low-cost handy tool to keep around for de-burring inside corners, etc. If used in a Micro-drill, stay below 7000RPM, and dunk in water to keep them cool. They are perfect to use in a pin vice drill.

 

[Mikey98118]

Keyed micro drill chucks from China

Keyed micro drill chucks from China are surprisingly well made. But the cheap brass arbor used to connect them to DC micro motors are as likely as not to produce runout. However, all these chucks will accept steel JT0 shank adapters, which can be easily purchased online with 3/8” and ½” shanks.  

    If you have a drill press, they make excellent micro chucks to mount in 3/8” or ½” chucks. You can buy an acceptable micro chuck and a (ground true) steel shank adapter for as little as $21. Do not attempt to buy the cheapest available shank adapter and chuck, or you will end up with run-out. To buy a workable tool already assembled would cost at least $70.

 

LittleMachineShop.com 3/8" Straight shank to JT0 arbor (4632) $10.07: Through Amazon.com is recommended to provide a shank adapter.

 

AUTOTOOLHOME DIY mini hand drill Kit (available through Amazon.com for $10.29); consisting of a keyed chuck, shaft arbor, and a 12V DC motor, is recommended to provide a chuck.

 

Open the chuck all the way, insert the shank adapter, and give its end a single sharp rap. New chucks need tender loving care; lubricate them and baby them over sticking spots until they wear in a little bit. Open the chuck completely and put a drop of oil on one of the ways. Then, use the motor to completely close and open the jaws a few times, to spread the oil over all moving parts; repeat this procedure occasionally, to lubricate internal surfaces and protect against rust.

    What lubricant to use? I chose flex shaft grease, because I also have a flex shaft to keep maintained. If you choose oil, turn the chuck upside down in a cardboard box, before running the chuck in a drill or press; to catch the excess oil that comes flying out.

[Frosty]

2 hours ago, Mikey98118 said:

to catch the excess oil that comes flying out.

Spoil sport!

Frosty The Lucky

[Mikey98118]

Finally; a powerful rotary tool with a 1/4" keyed chuck!

The Votoer XDMJ-260-B2 is a true rotary tool, unlike the heavier Votoer die grinder, which is discussed a little further on; they called it a rotary tool because it can run 1/8” accessories, but it is actually a full-fledged die grinder that is capable of running ¼” accessories; it also has full power, larger size, and greater weight of a short body die grinder.

    This tool has a full 260 watt brushed motor, and has the smaller lighter body of a rotary tool, but it has a 1/4” keyed chuck, which also accepts ¼” mandrels; these are stronger than 1/8” mandrels; especially for surface cutting jobs. Speed adjustment is from 5,000 to 31,000 RPM, controlled with a Dremel type sliding switch. I advise leaving the speed control on high, and plugging it into a 120V speed controller for the same reasons as it is suggested for the Black and Decker rotary tool; higher amperage load than standard 160-watt tools. This grinder comes with two spare carbon brushes, a chuck key, and 35 rotary accessories; $48 through Amazon.com.

[Mikey98118]

The VOTOER 480W Rotary Tool is actually a full-power compact die-grinder that can be used as a micro drill; it’s called a rotary tool because it can run rotary accessories (3/32” and 1/8” shanks), but it has three times the power of an average rotary tool; it has a keyed chuck that varies from .6mm (0.024”) to 6.5mm (1/4” plus 0.006”); it not only mounts ¼” shanks for more rigid cutting mandrels, but all of the micro drill bit sizes you will need. Variable speed adjustment is from 5,000 to 32,000 RPM. This tool should run at about 20,000 RPM at the mid-range setting on a fan or router speed controller during surface cutting; only the Votoer 260 has as low a minimum speed rating, for micro drilling. The large air vents provide good cooling; they face forward, to help exhaust air blow dust away from the tool’s rear air entrances.   

    Some serious accessories that can help build your burner are included with the one offered on Amazon.com, along with a spare set of brushes. Tool length is 11” and body diameter is just under 2-1/4”; it should be comfortable to hold, as a two-handed tool, even in small hands. Don’t attempt to run it one-handed—or any other tool with this much power.

    The electrical switch is a rocker type, and located at its bottom, near the rear of its motor housing (not on its back face), so it will greatly benefit from the addition of a safety handle (mounted on its chuck housing).

    Do a careful job of mounting the safety handle and it can support an acrylic guard too. Cut the guard from a plastic water glass. Combined with a sheet metal handle, inward facing set screws near the bottom of the glass are used to trap the whole assembly on the grinder. Multiple set screws, placed between the inward facing screws, and facing upward into the bottom of the glass, can hold a sheet metal safety handle on it.

[Mikey98118]

There's a new kid in school

(The RTX-6 has slipped to number two on my list)

The Votoer XDMJ-260-B2 is a true rotary tool, unlike the much stronger Votoer 480W, which the seller describes as a rotary tool because, thanks to a keyed chuck, it can run 1/8” accessories; but it is actually a full-fledged compact die grinder that has full power (480 watts), a third larger body, and the greater weight of a die grinder.

    This tool has a 260-watt brushed motor (the most torque of any rotary tool); it has the smaller lighter body of a rotary tool, but has a .6mm (0.024”) to 6.5mm (1/4” plus) keyed chuck, which also accepts ¼” die grinder mandrels; these are stronger than 1/8” mandrels; especially for surface cutting. ¼” burrs also have far stronger shanks than 1/8” burrs, so they can extend further beyond the spindle, without bending at high speed; that’s handy for grinding inside of tubes and pipes. Speed adjustment is from 5,000 to 31,000 RPM, controlled with a Dremel type sliding switch. I advise leaving the speed control on high, and plugging it into a 120V fan or router speed controller for the same reasons as is suggested for the Black and Decker RTX-6 rotary tool; a higher amperage load than standard 160-watt tools. This grinder comes with two spare carbon brushes, a chuck key, and 35 rotary accessories; it’s $48 through Amazon.com. Alas, this tool has no convenient place to mount a clear safety shield, so be sure to wear adequate head protection; glasses, plus face shield.

    Keyed chucks are tightened gradually, by using the key in all three holes in turn: 1, 2, 3, 1, 2, 3…until the drill bit, or accessory shank, is tight.

    New chucks need tender loving care; oil them and baby them over sticking spots until they wear in a little bit. Open the chuck completely and put a drop of oil on one of the ways. Then, use the motor to completely close and open the jaws a few times, to spread the oil over all moving parts; repeat this procedure occasionally, to lubricate internal surfaces and protect against rust. So, what to use? Try grease, WB-40, or 3-in-one oil. Turn the chuck upside down in a cardboard box, before running the tool, to catch any excess oil that comes flying out.

[Mikey98118]

Miniature adjustable three-jaw rotary chucks: A keyed chuck needs to have reasonable quality to successfully spin an accessory, or drill bit, at high speed. So, what about the key-less chucks (hand tightened) for rotary tools sold on line and through jeweler’s supply stores; the kind that has independent moving jaws? I bought three of these cheap imports, before giving up; they all froze, and broke during their first attempted use. Why? It turns out that none of them were actually a Dremel 4486 Keyless Chuck. Dremel has their brand name to protect; anonymous drop shippers don’t. Make sure that you are purchasing your “Dremel” chuck from Dremel. What is clever about this chuck is that they designed it to thread directly unto a standard rotary tool’s 9/32-40 threaded spindle, greatly increasing its stability, by making an end run around the weak spot in most rotary tool chucks—their skinny shanks (there’s a joke in that somewhere).

    While better than no-name imported chucks, it is still not anywhere near as good as a miniature keyed chuck on a micro-drill motor. However miniature keyed chucks often suffer from the poorly machined brass arbors that come with them. It is better to buy a steel JT0 arbor for them, to avoid run-out problems (some of them are made for use on DC motors).

 

Foredom A-MC2 Micro Chuck:  Foredom makes a rotary tool chuck from high-speed steel, which works okay; it is one of the older kinds, which employs a castellated collet that squeezes all four jaws closed as a single unit, to create a variable diameter chuck; it still isn’t as smooth as a set of brass drill bit collets. Why not? It is machined to about 0.001" (one thousandths of an inch) tolerance, and extends well beyond the spindle’s end. Really smooth performance in this instance would probably require 0.0002" (two ten-thousandths of an inch) tolerances; producing that level of quality would price it out of the market. What this chuck actually does best is act as a protrusion, to help extend the reach of grind stones and drum sanders deeper into small tubes (that need to be increased a few thousandths of an inch in diameter for fit-up). Remember to dress any stone, or revolve any drum you spin in it (to reduce run-out), before inserting it into the work.

    Accessories with 1/8” shafts are cheap and easy to find; this variable chuck is used to accept standard twist drill bits, which have varied shaft diameters. Google “adapter chuck for drill bits” or “Foredom® A-MC2 Micro Chuck” to see what is currently available. Do be sure to read customer feedback about any chuck you find tempting; good designs don’t count for much unless their quality control is up to snuff.

[Mikey98118]

 

   

The Dremel #100 single-speed, and #200 two-speed rotary tools both have a 108 watt (.9 amp) brushed motor; less torque is a plus for cutting small air openings in burners. This is the weakest motor in the smallest package you can find in a good quality rotary tool. The #100 and #200 are the oldest models left in Dremel’s product line; they have stayed popular this long because of their dependability; they are lighter, and smaller than other rotary tools (making them easier to grip and use).

    The #100 runs at 35,000 RPM, but becomes variable speed when plugged into a router (or fan) speed controller. The #200 has two speeds; 15,000 and 35,000 RPM. Dremel’s product manual states that “use of an external speed control will damage variable/two speed electronics.” No problem; just buy a #100. If you already have a #200, remember that the only difference between them is their control witches, which are low priced, interchangeable, and plug in (not soldered in place); you can buy either switch online, and change them back and forth at your convenience.

    These tools have plenty of air vents that are properly positioned; their prices are high (usually $50 for the #200, and $40 for the #100; but at times as low as $34). However, the percentage of their critical reviews are very low. On/off and high/low speeds are controlled by a single switch near the tool’s rear on the #200; and with an on/off switch located in the same place on the #100. Most people find this convenient. I like more safety when cutting, but this is a weak enough tool to overlook that shortcoming; especially if you only mount the thicker 15/16” Dremel #420 discs (safest), or standard 1-1/4” fiberglass reinforced cutoff discs (acceptable) for surface cutting. The switch location makes the practice of stopping a cutting disc before removing it from the kerf, a little awkward, but it can be managed, by using both hands. Place one hand on a safety handle, and the other over the rear of the motor housing. Lean forward over the work, while looking at the cut line through a clear plastic shield.

    The #100 and #200 are available through Amazon.com. The #200 is also available at Homedepot, Lowe’s, and Ace hardware stores. Unlike the bulk of rotary tools, both of these have parts available online, at reasonable prices; even the armature. You will also find diagrams, and repair videos for them online; the other reason people put up with sticker shock.

    Thread size for the plastic housing cap on most rotary tool’s plastic bodies match up with Dremel’s. You can change flexible drives and other attachments between most of them. Collet nuts can be a different story. Most rotary tools have interchangeable collet nuts. Spindles on the #100 and #200 models are smaller, so collet nuts from other rotary tools, will not fit them, and their fan will fit these, but don’t fit other tools. Yet, Dremels variable chuck will fit on most other spindles’ but not these. For fine detail work, these two rotary tools are very hard to beat.

    Mounting a handle will improve stability while you are cutting, and therefore, the quality of your work.

    The Autotoolhome electric grinder cover, appears to be no different than a Dremel A550 rotary shield, and fits on most rotary tools, including these.

   

The Gyros 40-00470 PowerPro Rotary Tool is available through Amazon.com, and at Loews, and Homedepot hardware stores; it is comfortably small; a few ounces lighter, a little shorter, and a littler fatter than the two Dremels you just read about; it only has a 144 watt (1.2 amp) brushed motor, with an 8,000 to 35,000 RPM speed range. A router speed controller will reduce its speed closer to drilling speeds needed for threaded holes, while protecting its delicate inbuilt speed circuit; when it comes to micro-drilling in steel, its lower-than-average minimum speed becomes helpful. 

    The tool comes with brass collets for 1/32”; 1/16”; 3/32”; and 1/8” drill bits. A Dremel keyless chuck is a workable alternative for a micro-drill’s keyed chuck, but only to drill up to 1/8” (0.125”) bits. You will have to enlarge the holes with something else for 8-32 size set screws (a #29 drill bit is 0.138” and a (#27 drill bit is 0.144”).

    Buy your PowerPro through Amazon.com, and you can add a four-year parts, service, and return shipping warranty for $4. Unfortunately, the ‘shipping and handling’ charges are steep with their offer. “nothin’s fer nothin,” remember? You will find way too many critical reviews listed for this product; but they are old reviews. Contrasted to that is an excellent warranty available nowadays. It looks like the OEM has been improving this tool for several years. Mine runs smooth as silk.

    The locking pin that is used to stop the spindle (while inserting or removing an accessory) was reputed to be weak; it’s a steel pin now.

    The power switch is on the tool’s rear face, making the practice of stopping a cutting disc before removing it from the kerf, impractical, but it can be slowed almost to a stop. There is a sliding speed dial in the same place as Dremels #100 and #200 models. But you must turn the speed back up as soon as the disc is out of the kerf; the motor will be heating up will it is stalled. Mounting a separate handle will improve stability during most of the time you are cutting, and therefore can improve the quality of your work.

    The Dremel 100 and 200 are the only high-quality tools with weaker motors than this; weak and quality don’t often go together.

    Choosing one of these three rotary tools is a compromise; are any of them an ideal alternative to micro-drills? No; it’s just one more alternative.

    So, why not buy an RTX-6, or 260W? This isn’t a choice about which tool gives you more bang for the buck; it’s a choice of which tool will prove more convenient for really small cutting tasks. When building a 1/2” burner, one of the more powerful tools should be your choice. 3/8” burners can benefit from less power, when cutting out their smaller air openings; with help from a router speed controller, you could go either way. ¼” burners call for an even more delicate touch, when reshaping air inlets. You can’t just turn down a controller below half speed for extensive periods. So, less amperage in a tool with a lower RPM range is the obvious choice for some of this work (8,000 versus 12,000 or 15,000 minimums, also means that drilling can be done at slower RPM).

    Why pick this tool? It has a nice shape and size; so does the RTX. It has a good warranty available; it should at this price. So, “for why already?” There are four things that will kill any rotary tool: stressing its built-in speed controller; frequently heating up its windings; dust; and damp storage. Lots of rotary tools have sufficient air entrances; strangely, most of them don’t have smart air exit designs. This tool has as many air exits for better heat dissipation; they are aimed to blow dust directly away from the tool’s delicate innards. Proper storage is up to you.

    The PowerPro must first be run from four to six minutes to seat its carbon brushes, before being used; during that period the tool vibrates more than usual, and its speed pulses badly. After the brushes seat, my tool vibrated no more than an RTX, and without any more pulsing.

    All motors with VDF speed controllers (including this one) have a high-pitched whine, whether the speed control circuit is engaged or not; the noise is electronically produced in their motor windings.

   The collet nut is well made and chrome plated, leaving its inner bevel smoother. The four collets that come with this tool are smooth brass; consequently, sticking collets shouldn’t be a concern. 

    The Autotoolhome electric grinder cover, appears to be no different than a Dremel A550 rotary shield, and fits on most rotary tools, including this one.

    One satisfied customer made a YouTube video that is actually worth watching:

http://www.youtube.com/watch?v=bWgo_5cyzOY

[pnut]

I found this rotary tool at the local pawn shop for eight bucks (marked 15) and have pretty good luck with it. It's definitely an off brand but it seems to punch above it's weight. 

In case you can't read it 

120V 1A

8,000-30,000 RPM

Pnut

[Mikey98118]

The photo is too blurred for me to read the text, but the black plastic and larger diameter of the motor housing looks like one of the old Moto Tool type rotary tools, which Dremel became famous for; they used the old style DC motors, which were larger/ heavier then today's motors. On the other hand, they were quieter, and much longer lasting, too.

Looks like you found yourself a bargain

[Mikey98118]

Chicago Electric markets a low-priced rotary tool ($23; $18 during sales) with a few accessories (that don’ t get kindly reviews); it’s louder than I like, and larger than the Black and Decker; it only produces average torque, with variable speeds from 8,000 to 35,000 RPM from its 160-watt brushed motor. This is a better than average speed range in the low end, which is helpful for micro drilling. My tool has held up pretty well for several years, with occasional use; some of them don’t. Heavy vibration is typical in this tool; they are sold through Harbor Freight Tools stores, and through their web site.

    The power switch is a rocker type, located in the pistol grip. The old switch wasn’t easy to turn off, but the latest switch doesn’t have that problem.

    If the speed control circuit on one of the best rotary tools is its Achilles heel, how long would you expect this one to last? Employ a router speed controller, or leave the tool on its maximum setting.

    So, why not discuss other cheap rotary tools? Harbor Freight’s return policy and numerous physical stores to take a reject back to is why. A drop shipper is likely to have nothing more than an ad site on the Net, and behave like a black hole, when you have a complaint.

    Why not give up endless shopping and “just buy a Dremel”? Well, the oldest models still available in the Dremel lineup (their #100 and #200) still get excellent reviews; the others? Not so much; compare their high prices versus the amount of critical costumer reviews, and Harbor Freight starts looking like a lot better deal.

    Am I saying that Dremel power tools are no darn good? No; I’m suggesting that you forget blind brand loyalty; this isn’t your grandad’s world. I despise the Black and Decker brand, and have still bought three of their RTX rotary tools, starting with an RTX-3; my third is an RTX-6; personal animosity hasn’t prevented careful consideration of their products. Why three of them, if they’re so great? I burned out the speed control circuit on the first one, and having no clue about what went wrong, or how to fix it, threw the tool away—unnecessarily. The second is still running fine, and I call the third one a back-up; but it’s really all about tool greed.

    Keep reading costumer reviews, and forget brand names; they’re increasingly irrelevant. Do we all wish this wasn’t so? Sure, but it is; so, deal.

    The Autotoolhome electric grinder cover, appears to be no different than a Dremel A550 rotary shield, and fits on most rotary tools, including this one.

   

[Mikey98118]

Freeing up jammed accessories: Collet nuts on rotary tools may need to be sharply rapped once or twice with the tool’s tiny wrench, to free up jammed accessories. Unscrew the nut a partial turn, so that the accessory can slide free; sometimes, they will revolve, but cannot be slid forward and removed. What has happened is that the collet, which the accessory’s shank slides into has jammed in place, locking the accessory’s shank together with the collet and nut. Tap sharply, on the end of the nut with nothing larger than the tiny wrench that comes with the tool; this will transmit just enough of a shock wave through the three parts, to break the collet’s grip.

    Should a new tool come from the factory with the collet stuck in place, unscrew the nut a couple of turns, and poke the shank of an accessory against the top of the collet (at an angle), to break it loose.

    If you change accessories frequently, you may find relief from this irritation with a brass collet; brass collet kits, which include 1/8” collets, sell for around $5.00 on eBay and Amazon.com. Just as some collets release better than others, some collet nuts are better too. Most collet nuts fit other spindles, so switching a better collet nut from a less used rotary tool to your favorite, should be an obvious move.

    Some people simply replace the collet nut (and its sticking collet) with a Dremel keyless chuck. Make sure to buy this attachment from Dremel; a cheap look alike won’t work very long, if it even works at all. How clever is this move? Enough that rotary tools are now being sold with this kind of chuck, instead of a collet and nut. Nothing succeeds like success.

    That said, even the Dremel chucks aren’t problem free; . Keyless chucks cannot be tightened anywhere near as effectively as keyed chucks, or collet chucks, and these tiny keyless \chucks increase that problem; obviously, your whole hand can tighten a keyless chuck on a drill motor far more easily, than a finger and thumb can tighten one of these. So, you may end up using pliers.

 

[Mikey98118]

The Dremel #100 single-speed, and #200 two-speed rotary tools both have a 108 watt (.9 amp) brushed motor; less torque is a plus for cutting ever smaller air openings in small burners. This is the weakest motor in the smallest package you can find in a good quality rotary tool. The #100 and #200 are the oldest models left in Dremel’s product line; they have stayed popular this long because of their dependability; they are lighter, and smaller than other rotary tools (making them easier to grip and use).

    The #100 runs at 35,000 RPM, but becomes variable speed when plugged into a router (or fan) speed controller. The #200 has two speeds; 15,000 and 35,000 RPM. Dremel’s product manual states that “use of an external speed control will damage variable/two speed electronics.” No problem; just buy a #100. If you already have a #200, remember that the only difference between them is their control witches, which are low priced, interchangeable, and plug in (not soldered in place); you can buy either switch online, and change them back and forth at your convenience.

    These tools have plenty of air vents that are properly positioned; their prices are high (usually $50 for the #200, and $40 for the #100; but at times as low as $34. Amazon.com). However, the percentage of their critical reviews are very low. On/off and high to low speeds are controlled by a single switch near the tool’s rear on the #200; and with an on/off switch located in the same place on the #100. Most people find this convenient. I like more safety when cutting, but this is a weak enough tool to overlook that shortcoming; especially if you only mount the thicker 15/16” Dremel #420 discs (safest), or standard 1-1/4” fiberglass reinforced cutoff discs (acceptable) for surface cutting. The switch location makes the practice of stopping a cutting disc before removing it from the kerf, a little awkward, but it can be managed, by using both hands. Place one hand on a safety handle (best) or at the neck (workable), and the other over the rear of the motor housing, with your thumb on the switch. Lean forward over the work, while looking at the cut line through a clear plastic safety shield.

    The #100 and #200 are available through Amazon.com. The #200 is also available at Homedepot, Lowe’s, and Ace hardware stores. Unlike the bulk of rotary tools, both of these have parts available online, at reasonable prices; even the armature. You will also find diagrams, and repair videos for them online; the other reason people put up with sticker shock.

    Thread size for the plastic housing cap on most rotary tool’s plastic bodies match up with Dremel’s. You can change flexible drives and other attachments between most of them. Collet nuts are a different story. Most rotary tools have interchangeable collet nuts. Spindles on the #100 and #200 models are smaller, so collet nuts from other rotary tools, will not fit them, and their fan will fit these, but don’t fit other tools. Yet, Dremels variable chuck will fit on most other spindles’ but not these. For fine detail work, these two rotary tools are very hard to beat.

    Mounting a handle will improve stability while you are cutting, and therefore, the quality of your work.

    The Autotoolhome electric grinder cover, appears to be no different than a Dremel A550 rotary shield, and fits on these tools.

The Gyros 40-00470 PowerPro Rotary Tool is available through Amazon.com, and at Loews, and Homedepot hardware stores; it is comfortably small; a few ounces lighter, a little shorter, and fatter than the two Dremels you just read about; it only has a 144 watt (1.2 amp) brushed motor, with an 8,000 to 35,000 RPM speed range. A router speed controller will reduce its speed closer to drilling speeds needed for threaded holes, while protecting its delicate inbuilt speed circuit; when it comes to micro-drilling in steel, its lower-than-average minimum speed becomes helpful. 

    The tool comes with brass collets for 1/32”; 1/16”; 3/32”; and 1/8” drill bits. A Dremel keyless chuck is a workable alternative for a micro-drill’s keyed chuck, but only to drill up to 1/8” (0.125”) bits. You will have to enlarge the holes with something else for 8-32 size set screws (a #29 drill bit is 0.138” and a (#27 drill bit is 0.144”).

    Buy your PowerPro through Amazon.com, and you can add a four-year parts, service, and return shipping warranty for $4. Unfortunately, the ‘shipping and handling’ charges are steep with their offer. “nothin’s fer nothin,” remember? You will find way too many critical reviews listed for this product; but they are old reviews. Contrasted to that is an excellent warranty available nowadays. It looks like the OEM has been improving this tool for several years. Mine runs smooth as silk.

    The locking pin that is used to stop the spindle (while inserting or removing an accessory) was reputed to be weak; it’s a steel pin now.

    The power switch is on the tool’s rear face, making the practice of stopping a cutting disc before removing it from the kerf, impractical, but it can be slowed almost to a stop. There is a sliding speed dial in the same place as Dremels #100 and #200 models. But you must turn the speed back up as soon as the disc is out of the kerf; the motor will be heating up while it is stalled. Mounting a separate handle will improve stability during most of the time you are cutting, and therefore will improve the quality of your work.

    The Dremel 100 and 200 are the only high-quality tools with weaker motors than this; weak and quality don’t often go together.

    Choosing one of these three rotary tools is a compromise; are any of them an ideal alternative to micro-drills? No; it’s just one more alternative, but they are handyer on ¼” burners.

    So, why not buy an RTX-6, or 260W? This isn’t a choice about which tool gives you more bang for the buck; it’s a choice of which tool will prove more convenient for really small cutting tasks. When building a 1/2” burner, one of the more powerful tools should be your choice. 3/8” burners can benefit from less power, when cutting out their smaller air openings; with help from a router speed controller, you can go either way. ¼” burners call for an even more delicate touch, when reshaping air inlets. You can’t just turn down a controller below half speed for extensive periods. So, less amperage in a tool with a lower RPM range is the prefered choice for some of this work (8,000 versus 12,000 or 15,000 minimums, also means that drilling can be done at slower RPM).

    Why pick this tool? It has a nice shape and size; so does the RTX. It has a good warranty available; it should at this price. So, “for why already?” There are four things that will kill any rotary tool: stressing its built-in speed controller; frequently heating up its windings; dust; and damp storage. Lots of rotary tools have sufficient air entrances; strangely, most of them don’t have smart air exit designs. This tool has as many air exits for better heat dissipation; they are aimed to blow dust directly away from the tool’s delicate innards. Proper storage is up to you.

    The PowerPro must first be run from four to six minutes to seat its carbon brushes, before being used; during that period the tool vibrates more than usual, and its speed pulses badly. After the brushes seat, my tool vibrated no more than an RTX, and without any more pulsing.

    All motors with VDF speed controllers (including this one) have a high-pitched whine, whether the speed control circuit is engaged or not; the noise is electronically produced in their motor windings.

   The collet nut is well made and chrome plated, leaving its inner bevel smoother. The four collets that come with this tool are smooth brass; consequently, sticking collets shouldn’t be a concern. 

    A 3/4” opening will serve to hold a safety handle on the PowerPro just as well as on an RTX or Chicago Electric, or Dremel rotary tool.   

    The Autotoolhome electric grinder cover, appears to be no different than a Dremel A550 rotary shield, and fits on this tool.  

    One satisfied customer made a YouTube video that is well worth watching:

http://www.youtube.com/watch?v=bWgo_5cyzOY   

 

Pencil rotary tools, whether battery powered, or corded, are simply too weak to do effective work on any burner in this text. A major factor in an electric motor’s strength (torque) is motor diameter, and pencil rotary tools are built slender. There are larger diameter battery powered rotary tools available, but the better ones are as expensive as a top-of-the-line corded rotary tool, yet have too many fancy circuits that are inclined to fail.

    You might consider acquiring one of the better micro-drills, like the Wolfride Mini Hand Drill, instead of a pencil rotary tool, or a battery powered tool. You get a lot more for a lot less. 

 

[Mikey98118]

Why all this talk about rotary tools?

Rotary tools can replace a variety of other equipment for small-scale tasks. Today, most of these tools accept attachments, increasing their effectiveness; their use is only limited by your imagination. Cost once restricted rotary tools to professionals, but their expense has been declining for two decades, along with that of their accessories. During that period, rotary tool choices have multiplied, while steel working accessories have greatly improved; providing wonderful control for building small burners, and the equipment they heat.

   So, the why for me is apparent. But what are they good for, after your equipment is constructed? Any Maker would know the answer to that. equipment is all becoming lighter. Any mechanic is going to deal with sheet metal in the future; not with plate.So, tools built for dealing with plate are becoming less relevant.

[Mikey98118]

Why keyed chucks?

Keyed chucks first appeared on micro-drills, allowing chucks to open considerably wider than the standard 0-1/8" of jewelers chucks. This allows them to drill holes for 8-32 thread taps, which is the smallest thread size that socket set screws are useful in on burners.

Later, some die grinders started mounting keyed chucks, allowing them to be used with inexpensive rotary accessories (without worry about shanks that are supposed to be 1/8" but turn out to be undersized), along with standard 1/4" shank accessories.

Now, the first rotary tool, which also has a medium power die grinder motor, is available (the Votoer 260W); this also uses both rotary and 1/4" shank accessories, but has a 5000 RPM minimum speed, which allows it to drill holes in steel, by using cobalt or tungsten steel drill bits.

I believe that all these tool improvements are being driven by their use for sheet metal work by Makers. But they are even handyier for gas forge and burner construction

[Mikey98118]

 

To avoid surface cutting problems:

(1)  When starting a cut, be sure the accessory is already turning; do not start, or restart a cut, with the tool still.

 

(2)  Gently lower the disc unto the part surface, with the tool held firmly, and lightly run the disc back and forth on the part surface, to establish a groove. Deepen the groove by continuing to run the disc lightly back and forth, until it starts to break through the material’s far side; at this point, the groove is called a kerf. Don’t press the disc against the part. Just let the disc do the work.

 

(3)  Always delay actually cutting into the kerf until you have no other choice.

 

(4)  Start and stop the cut short of the end of the marked line, and finish the cut later, with a small diameter disc, for greater control, as these two areas are likely spots to create kickback problems.

 

(5)  Allow the disc to come to a complete stop before removing it from a cut, to help avoid jamming the disc, and creating kickback.

 

(6)  A common cause of kickback is a disc that is moving even a little out of parallel to the kerf (that slit in your part that is made by the disc); the problem is multiplied when the disc is deeply inserted into the kerf. It is safer to move a disc back and forth on the part surface, beside a scribe line, gradually deepening its grove, and only trying to cut through the material, after the disk begins breaking through the part.

 

(7)  Try to only move the disc counter to the direction that friction inclines it to “walk” along the part, while cutting into the kerf; this is to help prevent you allowing the disc to bump against the end of the kerf; always ease into it, to prevent kickbacks.

 

(8)  When you can, try to cut a little bit short of the cut line, and then grind back to it afterward; this allows you to concentrate on two separate tasks, instead of looking after too many aspects of the cut at one time.

 

    After you finish all cuts and remove unwanted sections, then start grinding back to the scribe or ink lines with a small stone wheel, or diamond disc. Do not use cutoff discs for grinding; it dangerously weakens them.

[Mikey98118]

Mounting a homemade safety handle: Rotary tools and die grinders can be braced for straight travel (similar to cutting with angle grinders), rather than the typical swinging arm motion (tendency to curve, binding the disc), by mounting a side handle near to the tool’s spindle; this provides improved control for surface cutting. Twenty years ago, 2” angle grinders like Proxxon’s Long Neck Angle Grinder, or the Merlin 2 from King Arthur Tools, were the only power tools that could easily make straight line cuts in small burner parts; they were designed for inline motion, and had steel safety guards. A rotary tool with a safety handle mounted can now do a better job, more safely, for a small fraction of their prices.

    What has changed, to make this possible? See-through safety guards couldn’t be purchased back then; they can be now. When cutting along an ink or scribe line, it is tempting to bend over the tool, to provide the best view; a very bad habit, unless the tool has a safety guard; it’s also frustrating to try to see the cut adequately with steel guards. But you can place your disc beyond the cut line, and work in safety and comfort, when you see the line by looking through the guard.

    Some rotary tools already have a removable plastic handle, but they are set up at about seventy-degrees for increased comfort during buffing, grinding, and drilling; not at right angles, for increased control during a surface cut.

Caution: Whether or not a handle improves the safety of your rotary tool, depends on power switch location and type; that can’t be listed for every model, since there is such a variety of on/off switch designs and locations. Mounting a handle will increase stability as you cut. But, stopping the tool before lifting a cutting disc from the kerf is considered “best practice.” It is good if the switch type and location allows this, with handle added. if switch type or location makes that impractical already, then no safety is lost by adding a handle. If the switch can be safely used to stop the tool during surface cutting at present, but adding the handle would change that situation, leave it off; this is quite unlikely, but possible.

[Mikey98118]

On 1/26/2022 at 5:27 PM, Mikey98118 said:

Keyed chucks first appeared on micro-drills, allowing chucks to open considerably wider than the standard 0-1/8" of jewelers chucks. This allows them to drill holes for 8-32 thread taps, which is the smallest thread size that socket set screws are useful in on burners.

I should have written "first reappeared", since keyed chucks all but disappeared from drill motors during the last four decades, except for smaller hammer drills; that makes a good tip-off of why they are superior to keyless chucks. Dremel's keyless chucks, which  open from 0" to 0.250" and are designed to thread directly onto rotary tool spindles, maintained the advantage over imported JT0 keyed chucks with jaws openings of 0.024" to 0.160" but  are only designed to spin up to 10,000 RPM,, and so could not be used on rotary tools. But with the introduction of a 1/4" chuck on the Votoer 260W rotary tool, every barrier to keyed chucks on rotary tools has been neatly bypassed; they will probably become a standard choice on the more powerful rotary tools 2 amp to 2.5 amps going forward.

[Mikey98118]

2 hours ago, Mikey98118 said:

which  open from 0" to 0.250"

Typo! that should have read "from 0" to 0.125."

[Mikey98118]

Micro drilling

 

There are two main reasons for drilling during construction of tube burners; one is making holes to be threaded for 8-32 socket set screws with taps that call for #29 drill bits (0.1360”) for 75% thread engagement through thin tubing walls, or #27 bits (0.1440”) for 50% thread engagement through thick or doubled walls of flame retention nozzles.

    Drilling is also used to create controlled starting and ending points for cutting out air openings. Corner holes can then be enlarged along both of their cut lines, with 1/8” tungsten carbide rotary files, to help simplify material removal; use only the conical shaped files for this purpose.

    Any speed chart should make it plain that finding a good drill motor for threaded holes isn’t a given. 1/4” variable speed drill motors have the right speed range; 3/8” drills come close, but may be a little slow. Mounting an adapter chuck within the larger chuck of a drill press allows them to spin the smallest micro bits needed. At the present price for 1/4” variable speed drill motors, you can buy a five-speed drill press from Harbor Freight Tools (and other sources) for about the same money as the right ¼” drill motor for the job.

Run-out (AKA runout): Any rotating tool is meant to revolve on its center. If its spindle isn’t machined true (centered and parallel to its axis), a rotary tool, or die grinder will orbit in a tiny circle around its axis, instead of revolving on it, producing heavy vibration; this is called run-out.

    If a micro drill’s keyed chuck isn’t mounted true on the motor’s spindle, because the tiny brass arbor that connects them wasn’t machined true, the micro drill bits chucked in such a tool will also orbit around a small circle, and quickly break.

 

[pnut]

Does anyone know a good source for brushes for a rotary tool motor? My rotary tool is producing visible sparks in the motor housing and not wanting to start without spinning the chuck. I'm going to disassemble it and blow it out and clean everything but I'm pretty sure it's the brushes that need replaced. 

 

Pnut

[Irondragon Forge ClayWorks]

I've had good luck with ereplacementparts . com they had brushes for a very old Dremel and a small older bench glass grinder we have plus other stuff for some old counter top appliances.

[George N. M.]

Depending on the age and make you might try contacting the manufacturer.  Oddly, my cheap HF, Chinese made, rotary tool came with a set of extra brushes, something my dremels never have.

"By hammer and hand all arts do stand."