reefera4m

Thanks Glenn, This should have been the tone for all the replies. I'm all for CONSTRUCTIVE criticism, just not the patronizing comments of some who replied. And I'd add one caveat - take the GOOD advice of others and ignore the rest. They'll always be someone that just can't help giving negative comments but don't let them bother you.

JMANN, Every time I read this thread I get more annoyed. Many of the responses by the 'experts' are not only condesending in tone (and in some cases arrogant as well) but inaccurate as well. A 20 Ton 'Mini-Press' made with a Harbor Freight Air-Over-Hydraulic Jack is not an 'explosive danger'. Having made several of these presses and tested one to destruction, the only danger is getting you finger pinched off if you put it between the dies while simultaneously operating it. I'm not a 'professional' or 'certified' welder although I have taken several Tech College classes on welding. My welds aren't alway perfect but they're more than adequate. I use a Millermatic 180 (5/16" single pass) MIG Welder 25/75 mix. After I built and used my first mini-press for a couple of years, I decided to build another. Once the 2nd one was complete I decided to do an extensive stress evaluation of the first one. Some of the thing I did were: Test 1. Replaced grade 8 bolts with grade 5, then grade 2 Results - none of the bolts failed but the grade 2 did deform. Test 2. Replaced 1/2 bolts with 3/8" grade 2 Result - the grade 2 bolts failed after repeated cycles - the bolt sheared but the top anvil only moved about 1/2 -3/4 in. The jack did not have enough speed or reach to project the anvil off the press. Test 3. Ground the welds holding the uprights flush so that only the penetration part remained Result - couldn't get uprights to fail Test 4. Ground the welds below flush (actually cut into penetration) Result - eventually got the welds holding the upright in place to fail, However they failed gradually - i.e. they stretched, bent and the ripped rather than breaking violently. To get total failure I had to continuously operate the jack - continuing to stretch, bend and tear the welds apart. The welds started to fail at the thinnest point and gradualy continue on. With a much faster or larger jack the failure could have been quicker or more pronounced - but explosive???? Test 5. For my own edificaton I cut cross-sections of the welds . They were for the most part quite reasonable - good penetration, little or no porosity. Bases were reinforced with overlapping filet welds - way overkill! I subsequently did some internet research on bolt shear strength - I could have save myself the time and destruction of the first press. Properly installed with the full shank in the shear zone, all 1/2" bolts are adequate for a 20 ton press. I still use grade 8 so I don't inspect as often. I also researched the shear strength relative to the shear plane thickness and bolt tension - again 1/2" bolts are more than adequate. And I went back to my welding text book 'Welding Skills 3rd Edition B. J. Joiner, R. T. Miller' and also did some additional internet research on weld strength and material strength. Using 1/4" wall 2"x 2" mild steel square tubing and a decent 1/4" filet weld all around the upright bases (I also welded the uprights to the welded center) would be more that adequate for the 20 ton press. Adding overlapping filet welds is overkill but cheap insurance against repairs. My bottom line is this: Replies to JMANN could have been much more constructive and should have been much less condesending. Many of us who visit this forum are hobbyist looking for help not discouragment. None of this is brain surgery - although one should do some research and practice the basics. While Jmann's press may need some additional work, I hardly think its dangerous. His welding does need some improvement but that doesn't mean he should give up and take it to an 'expert'. PS All the 'mini-presses' I've made have cost well under $200, including the Jack.

I've drilled and tapped black iron to recieve a .030 MIG nozzle for my venturi forges. Worked find with a little pipe dope or teflon pape. I once made the mistake of trying to use a .030 MIG nozzle that had metric threads - which naturally leaked. A little J-B Weld solved the problem, didn't need to braze or solder. Here's a photo of the MIG tips on a 3/8" black iron (steel) plug

Should have read 'edge thinner than spine' my bad -

Lendlas, Assuming burners of the same size, two will heat faster (much faster) than 1 and sometimes use less fuel. I've found that in my 7" diameter, 12" long forge, it loses heat faster with just one burner and requires more fuel to compensate. When I switched to two burners the forge heated up faster and retained the heat easier. While the faster heat was expected, the heat retention I can only attribute to the fact that one burner is trying to heat the entire forge and losing heat at both ends. Two burners each heating half the forge operate at a lower fuel flow and it seems to be less that half the one burner comsumption. That is on MY forges in MY shop and may not be universally true. What I really wanted to address is your concern about 'even heat'. IMHO this is the most overrated aspect of a forge! I've built a number of forges, mostly venturi forges (see other venturi threads) and a couple of blown forges. After spending hours designing and building a venturi forge that had a great 'heat/flame swirl' and a pretty darn even heat distribution (checked with a pyrometer and various locations inside the forge) I discovered that it makes very little, if any, difference in forging perfomance. What - how can that be! Conventional 'wisdom' says even heat is the 'holy grail' for forge design- the 'swirl' is important! NONSENSE. No matter how even the heat is inside the forge, any metal you put in will heat unevenly! Take for example a knife blade - the tip is thinner that the base, the spine thinner that the edge. In a forge with perfectly uniform heat the tip and edge with heat faster and get much hotter quicker. Even if you put in a perfect sphere of metal in a perfectly uniformly heated forge, it will heat unevenly. If it rests on the floor of the forge the bottom will heat slower, if you hold it with tongs where the tongs touch it will be uneven. I've tested this and know it to be true. That is why you see experienced smiths, blacksmiths and bladesmiths, moving their work pieces around within the forge. This is perhaps most critical when heat-treating. Getting the most uniform heat in a piece of steel before quenching is critical and expecting that to happen just by putting the workpiece in a uniformly heated forge is a recipe for failure. Best case it will simply heat unevenly, worse case you'll burn away some metal while leaving other parts below critical. While I've done a fair amount of forging (and forge welding) myself, I've watched many, many others, particularly bladesmiths, forge metal. I have yet to see one achieve an even heat without moving the piece around inside their forges. Unless you can design and build a forge that you can regulate AND adjust the heat in minutely controllable zones, don't waste your time trying to build a forge with uniform heat. Better to spend you time positioning and repositioning your metal to heat evenly. Is the concept of a uniformly heating forge something to aspire to - or just a marketing ploy to differentiate one commercial forge from another or justify the cost - you decide, I already have.

To answer your question - yes that looks like a neutral flame - the best kind for general forge work. I've found that tuning forge burners, regardless if they are venturi forges or blown forges, is just a matter of adjusting the amount of air relative to the fuel. OK that sounds like a no-brainer but whenever you adjust the fuel pressure you have to compensate with the air flow. There are a lot of examples on how to do this if you look under oxy/acetelyene welding - even a number of YouTube videos. I usually start by setting the fuel flow/pressure at what I expect to use (forging or welding) and then I adjust the air to reach a neutral flame. If you have to error do so in the carburizing (akso called reducing) side - more fuel than air. Worse case you'll heat slower and achieive lower temps (and theorectically add back some carbon). The worst flame is one with too much air (oxygen) appropriately called an oxidizing flame. It does just that - causes the metal to oxidize. Without seeing how you burner regulates air flow I can't help with the adjustments, My homemade blown forge has a simple plate that slides over the air intake of the blower reducing the air. On my homemade venturi forge I have two adjustments available; 1) moving the nozzles in or out of the venturi cup or 2) positioning a reducing plate over part of the cup. Here's photo of the venturi setup:

I also get mine at a place that sells wire rope and services the shipping industry around Seattle, WA. They always have scrap pieces and I gotten so really good stuff for free. The most I've had to pay us maybe $.50/lb (scrap value). Ususally I don't even have to think about a spark test - they have the specs available! I would think there would be a number of similar places in the NE.

The most valuable material you can salvage, by far, is the track itself! The 'HC' spikes might make decorative knives (I've made more than a few) they won't harden much, if at all, even with the best heat treatment. They are designed with low carbon content so they'll bend before breaking. The track on the other had makes excellant anvils, most hobby blacksmith and bladesmiths I know have at least one (I have two and would like more).

I just read this thread and I have to disagree about 5160 containing nickel. I use 5160 a fair amount and to my knowldege is lacks any nickel at all. It is sometimes difficult to forge weld but I believe that's the chromium. On the other hand it welds easily with a MIG welder - and makes excellent anvil tools like cut-off hardys. It also makes a good blade on its owm Admiralty Steel and others show 5160 as: Carbon 0.56 - 0.64 Chromium 0.7 - 0.9 Manganese 0.75 - 1 Phosphorus 0.035 max Silicon 0.15 - 0.35 Sulphur 0.04 max

Eric, I just welded a couple of pieces 3/8" square steel tubing'guides to the bottom anvil support and the fabricated a sliding tool rest using 1/4" square tubing. The 1/4" slides through the 3/8" 'guides' easily but snugly. Since it is attach to the sliding part of the press it is alway at a usable position.

I started on coal/coke/charcoal forges so moving the piece comes naturally . Oldtime blacksmiths were constantly moving the metal to heat the right spot just the right amount - funny how when some things change others stay the same.

Even when taking care I seem to inflict damage to the refractory cement coating I use to seal and protect the ceramic wool. For periodic maintenance and repairing cracks or voids I use an inexpensive refractory cement like Meeco Mfg. Co., Inc. 611 Gallon Refractory Cement (3000 degrees) or Rutland 211 Dry Mix Refractory Cement 10 Pound (2500 degrees) and then coat the surface with ITC100. This has been the best and least expensive solution I've tried and works well. The ITC100 protects the cement from excessive heat and reflects the heat back into the interior of the forge - heats faster and hotter,

One of the keys for me is to make sure the entire interior of forge is hot before putting anything in it. Even with good burner design/placement creating a swirling flame, metal is going to heat unevenly. Blades are a prime example - even a forge with perfect heat distribution will heat the thin edge faster than the spine and the tip faster than the base. You just need to move the piece around to get even heat distribution - you can't expect the forge to compensate for the varying thichness of the metal. My forges have removeable rear covers, one with a slot for passing thin stock such as blades through. The rear covers/caps help hold the heat in and even it out. I spent an inordinate amount of time designing and build a forge to create a swirl effect and more even heat - still had to move the metal arould to compensate for thickness variance: Two propane forges - both heat uneven metal unevenly: Rear Covers: 1

Maybe - I used to frequent this forum before my old 'puter died. I may have met you at the Mt Vernon Hammer-in but I was just passing through and couldn't stay. Personally I just like to make my own tools whenever possible - forges (propane and coal/coke), air-over-hydraulic mini-presses, hardies, etc. Besides the 'puter problems I've been rebuilding by shop - two bits of advice - good insurance and lots of digital photos. Here's a photo of another 'tool' I made:

One more photo - after only two minutes plenty of heat!

Naturally aspirated/venturi forges can get up to welding heat with the right forge design. I don't know the all the physics behind behind the venturi effect but I know from my own experience with my venturi forges that you can easily alter the fuel/air mixture to obtain the best 'neutral' flame - with a simple sliding plate held in place by a magnet. I just move the plate to reduce the amount of air drawn in by the propane. For initial heating or forge weldingI use up to 12psi (propane) and full open venturi. For reheats or normal forging maybe half that. Here's a couple fo photos:- Dual burner venturi (2" diameter exhaust pipe venturi, 3/8" gas line, .030 MIG nozzle flowing into 3/4" burner pipe - nozzle position variable via threaded rod) The proof is in the forge:

I've used both Satanite and ITC100 and both will do the job of protecting and sealing the ceramic wool. What I prefer to do is use a less expensive refractory cement to protect and seal the wool and then use ITC100 as a top coat. The ITC100, as stated before, reflects IR (heat) and can substantially increase the apparent heat in your forge. Regardless of what you use to protect and seal the wool you will have to periodically maintain it.

They seem to. I saw one mounted upside down and it worked. I've had mine working horizontally when I was testing it. I don't know if the seals would eventually leak or not.

Here is a hot cut hardy I made from a section of rear leaf spring from a '78 Ford HD P/U - . The cutting blade is welded to a piece of 1" square bar stock taht fits in the hardy hole. After welding the whole thing was heat treated - heated to critical, soaked for 5 minutes and quenched in 104 degree (F) canola oil, then tempered at 400 degrees F for two hours. It works GREAT! I've cut 1/2 leaf spring steel (orange hot) almost in have with one blow fom a 6# sledge and never even dulled the edge! (the white spot on the edge is just a pice of cloth that go caught on it while wiping it off for the photo - my bad).

Naw, then I'd have to charge for it But the way, my only concern with my press was welding the uprights securely. I have a MillerMatic 175 (220V MIG welder) which will weld 1/4" plate in a single pass. I'm a fair hobby welder, but to to make sure the uprights would hold I beveled the bottoms of both uprights, cranked the welder up to the max for .030 wire and made a two-pass weld on three outer sides of the uprights and a one pass weld on the inside to the 3/8" base. Then I welded up the side of the uprights and across the top of the 2"x2"x1/4" square tubing base and then welded the the upright to the 1/4" top plate of the base. All in all I welded the uprights in 8 places, each weld at least 1/4" thick with the deepest penetration I could achieve. On the beveled ends I was able to get pretty much complete penetration and probably 70% on the rest of the welds. I'm pretty sure, and initial test bear me out, that the uprights won't EVER come off .

You're welcome. I'm going to make another one for a friend so I did a couple of extra things with my first one - a schematic and a cost list. The cost quote I got form a local supplier in WA and they were reasonable except for the 3/8" thick 10"x16" base plate. I got a piece from their scrap pile for $10 versus the $83 for a new cut piece. Here's the info (sorry the columns do not line up - the first column is as quoted, the second column is using scrap 3/8" and the 4th column is using 1/4 plate instead of 3/8"): Schematic: Cost: Description Quote 1/4" instead of 3/8 Scrap 3/8" Quantity (2) - 2”x2”x1/4” 24” lengths steel tubing (A36) or mild steel $23.80 $23.80 $23.80 Quantity (4) - 2”x2”x1/4” 10” lengths steel tubing (A36) or mild steel $ 20.83 $ 20.83 $ 20.83 Quantity (2) - 2”x2”x1/4” 8” lengths steel tubing (A36) or mild steel $8.92 $8.92 $8.92 Quantity (1) - 3/8” x 16”x10-1/2” sheet (mild steel) $83.35 $12.00 $20.00 Quantity (1) - ¼” x 8”x10 sheet steel (mild steel) $5.95 $5.95 $5.95 Quantity (2) - 3/8” x 12”x3” sheet steel (mild steel) $6.90 $6.90 $6.90 Quantity (2) - ¼”” x 12”x3” sheet steel (mild steel) $4.60 $4.60 $4.60 Cuts $14.00 $14.00 $14.00 Steel Only total Cost $141.57 $70.22 $78.22 Air over Hydraulic Jack- Harbor Frieght Sales Price $86.71 $86.71 $86.71 Totals w/Jack $228.28 $156.93 $164.93

Well, I finally finished my mini-press (well except for some more enhancements that come to mind). Mostly just a copy, thanks for the original idea Thunderfrom Dfogg! My Mini Press Uprights - 2"x2"x1/4" Base (boxed in by 1/4"x2"x8" flat stock) Base plate 16z" wide x 10" deep x 3/8" Base internal (4) 2"x2"x14" - 10" long Top Plate - 8"x10"x1/4" Bottom Die Holder - 2"x2"x1/4" - 8" long Sides - 2-1/2" x 12" x 1/4" Top Die Holder - 2"x2"x1/4" - 8" long Sides - 2-1/2" x 12" x 3/8" (2) Grade #8 1/2" bolts Dies - #1 = Plate 2"x3"x3/8 plate, 1"x1"2" mild steel Dies - #2 = 3/4"x2" Steel bar (lawn tractor axle stee) Some of my modifications: Quick Change Die Holder - Slip in one side and the center Long 'T'- Handle Hold Down Pin and 'T' - Handle - Tension Pin and Set Screw to hold tight Extendible Tool Rest Tool Rest/Die at Top Rear Hold Down Tool Tray

I'm trying to understand your 'you can't heat treat for flexiblility' statment. While I agree that the 'design' (as in blade geometry) is a significant factor (as is the steel you choose), I also know that heat treating can also affect flexibililty. If I were to take a leaf spring of 5160, 'flexible' in the beginning then forge and shape it to a common hunting knife shape then improperly heat treat it, it would end up either too soft and flexible (or just soft and bendable) or too hard and brittle. If I heat treat it properly the blade will have some 'flex' to it and yet be quite tough. When adding the 'edge quenching' aspect of heat treating, you harden the edge more that the spine with the intent of having an edge that will retain its sharpness while the softer spine will be more flexible and not as brittle. I consider the proper combination of annealing, normalizing, quenching and tempering to all be under the umbrella of 'heat treating'. The opposite of 'you can't heat treat for flexibility' would be you can "heat treat for brittleness'. Forget to temper and see how 'inflexible' the blade can be - just drop it on a concrete floor.

Not only do you need to use oil but you should pre-heat the oil to around 140 degrees. I've made several knives from truck leaf spring steel ('78 Ford HD) and the turned out great. Sharp enough to shave with, tough enough to chop hickory and flexible enough not to break. Another good tip I learned - sand the blade to with 220 grit - 400 grit sandpaper before heat treating. Eliminating deep scratches from grinding or rough sanding will go a long way in preventing cracking/shattering (unless you use water ). I also believe that a thinner spine will help as well. Sometimes the greater the differential thickness between the edge and spine, the greater the stress between the two will be when quenching. Not to denigrate the knife, the design of which I really liked, but a knife of that length and that thickness would probably either end up as a wall hanging or put away in a closet. Way to heavy to use or carry. Still it need not be practical to be good looking!

I asked this very question on another knifemaking forum and the replies were astounding. Most people are convinced that 1) such an idea would never work, 2) they didn't want a 'standard' to limit what they call their blades and 3)it would be too hard. I've seen knives called 'Bowie' that resemble ordinary Chef's knives, Skinners that resemble paring knives etc. etc. There should be a standard as with most products that are bought and sold to clearl identify the product. There can be individual variations but starting with a general consensus makes sense to me. Not as tough to get people to generally agree but way too much work for me to undertake such a project!