Reaming hole drill bit size?

[LA9436]

I apologise LeeJustice, I believe I jumped to conclusions, says a lot about my state of mind at the time.

Thank you for the advice Irondragon, I do use a file to connect the 2 holes but at my skill level, the drill bit does a much better job at getting a rounder circle than I ever could with a file.

Ill bear that in mind Thomas!

Got it! Frosty And thank again for the detailed instructions !

Edited June 7, 2022 by Mod30
Excessive quoting

[Frosty]

One more tip for you. No need to use the quote when you're talking to folks unless it's an old post or something specific you need to make a point. I understand responding directly to people is polite but it's not nearly as important here. Heck most of us don't agree half the time. So long as we're not calling each other names it's a happy place. People have their login names in the header and some of us use our name or nickname as a sign off. For example call me Frosty rather than quoting me. Make sense?

The moderators end up having to delete unnecessary quotes to save people in countries with dial up connections who have to pay for data bandwidth, so they end up working harder.  Keeping off the moderators watch list is a good thing.

I never clean up holes with a file I use a larger drill bit and turn it by hand. Just hold the bit in your hand and twist it in the hole, it will deburr and put a nice chamfer on the edge. 

Have you noticed I haven't used your login name once and you haven't had any trouble knowing when I'm talking to you? 

Frosty The Lucky.

 

[LA9436]

Ah yes, I was trying to be polite but this makes sense. Thank you.

[Frosty]

You're welcome, it's just another part of learning how to use the site. 

Frosty The Lucky.

[anvil]

I too deburr with a larger drill bit. If I have a few to do I put the larger bit into my drill instead of by hand. I then bring the hole to the bit and do both sides. I bring the hole up because I have better feel for just removing the burr. I don't want a countersink.

Instead of drilling over a wood block, I use a piece of channel iron. It doesn't take very long for a wood block to get pretty chewed up and out of level. I've been using the same channel iron for ever.   The first and  last pics shows how to drill a scroll. for many things you only need one piece of channel

[ThomasPowers]

I try to always clamp the piece I am drilling!

[LA9436]

Useful advice Anvil, and with pictures! Just out of curiosity, why do you not want to use a countersink?

[Frosty]

anvil: is that drill press hand cranked or powered? If it's powered you should go sit in the corner for not clamping the work down!

Remember, we're talking to someone just learning basic shop practices, we don't want to read about a bit jamming and fingers getting sliced up or broken do we? Old timers like many of us know when and how to secure work in a drill press but here on Iforge it's the time and place for text book safe practices. 

LA: By not countersinking the holes anvil means he only wants the bit he's deburring with to just kiss the parent stock, not drill into it like a countersink. This is just to clean up a freshly drilled hole. You've looked at the exit side and noticed the sharp burr. Yes? Using a larger drill bit to just kiss it will cut that off, you don't need or want more than a clean hole.

Frosty The Lucky.

[ThomasPowers]

I learned that a "real" 2 hp motor on a drill press will do a number on  me if a bit catches. So I have a bunch of different clamps I can use to hold different shapes.

[Frazer]

I use a countersink to deburr since I keep one in my hand drill 80% of the time for that purpose. Then I just drill the hole with the press, give it a quick shot with the countersink and it's done.

It's all the same IMHO, it just depends how you're set up. Not everyone has countersink bits, but most everyone has another drill bit. 

[Scott NC]

  Grandpa used to mount countersinks in wooden handles for quick cleanup of small holes.  Just a twist of the wrist.  I still have a couple of his.   Deburring tools are cheap and handy for relatively larger holes and can be used for deburring straight edges such as a saw cut or ground or milled stock.  They work well for pvc too.

[anvil]

A lot of feed back, a good thing.

Let me clarify on the countersink question. Its a good one. Use anything you want to remove the burr, but when removing the burr, don't do a countersink in your work, just remove the burr and slightly break the edges of the hole. This will enable your two pieces of iron to have full contact with each other when joined with a rivet. If there is a burr, There will be a space and you will have a loose rivet. Safety wise, removing the burr will keep you from getting small cuts. 

A counter sunk hole is used, at least by me, when I use rivets and one side is flush, not headed. If you have countersunk holes on the inner faces of your work, It is possible that the rivet will expand into the voids and cause a space between your two pieces of work, or not have enough material for matching heads. Thus a loose rivet. Its a good shop practice, in a blacksmith setting, to know the difference between a countersink and removing a burr. For what its worth, I always remove the burr, I countersink when necessary. Actually, I rarely use an official "countersink" to countersink my holes. I use a larger known size bit for specific rivet diameter and know how much extra rivet length I need to fill this depth and width of countersink completely and with no grinder cleanup to make them flush, or too little and lose structural strength.

As far as clamping,,,Pic #1 shows the setup for using channel iron instead of a wood block to back up your drilling and protect your table.. Notice there are two C clamps shown in the pic. Frosty, Why did you not show or mention, how to clamp on a wood block?   Most likely for the same reason I didn't. Lol. 

Please note: This may be info for more advanced smiths, and should be used with care by all. When you can clamp, clamp your work. If you can't figure out how to get the job done with a clamp, be aware and prepared for what might happen. We don't have an "Advanced Technique" section here.  In this case in pic #3, use a heavy long handled and long nosed tongs that will span at least two of the turns of your scroll or more. This will give you enough grab and mass to control your work. Lol, as for this pic, I'm usually using a quarter inch rivet on this size material. I use a 1/8" bit or smaller for a pilot and a 1/4" bit for the final. With these small bits, the problem when your bit grabs is you break your bits, not loose control of your work. Drilling scrolls is tough to learn, especially if your material is 3 dimensional or tapered like this one. Theres a good chance that a scroll of this type (pic #1&3) cant be clamped in a vice and still be able to see all your reference lines. Theres one reference that is missing here,,, because this is a test piece for making the scroll. If you look down the center of the bit, I always have a layout line to indicate the vertical view. 

Your bit will grab for two primary reasons: Your bit isn't sharpened correctly and you are either using auto feed and not paying attention or you are drilling manually and applying too much force AND not paying attention. Like Frosty said concerning exiting a hole, with experience, and awareness, you will feel the grab before it grabs. Then let up on the pressure. If you new guys aren't aware of this, then consider this the best advice in my post

Thomas, I'd love to see an actual pic of one of your clamps that you would use for drilling a 3 dimensional and tapered scroll on edge. This pic is a test piece for 80' of rail. Notice the top line of scrolls and their joinery on the bottom where the forge weld is. From the forge weld to the end of the rattail finial, its fully tapered, and the total line of the scrolls when drilled is the full length of each rail section. 

 

[BillyBones]

I had a friend years ago get a job at a machine shop. They told him on day 1 he would be running a deburring machine. They gave him one of those deburring tools. 

As far as those holes go there are multitude of reasons that can cause that.

As far as the original question the hole should be .015" - .020"(.381mm-.508mm) for machine reaming, now here is the important part ***that is a rule of thumb***. That is what i use to set up the job and may need adjusted to get the results i want. As a machinist i use the reamers to clean up the hole if i have a finish requirement and if i am running a tighter than normal tolerance but not to true the hole. If the hole is not true then it is a problem with the drill or work holding. 

Just to round up them holes though, i would just use a hand or T-handled reamer. 

[Frosty]

True, I didn't explain how to clamp a piece over a wood bolster and grant using channel iron is in many ways superior to wood. No question and I may have over estimated the general, world audience. Perhaps I shouldn't have assumed that much. Sure I kept my descriptions to a beginner's level, LA wasn't having trouble with an advanced problem.

What I am a little surprised about is your having to pilot a 1/4" hole. Don't you use split bits? You wouldn't be breaking so many, They'll bite miniscule punch marks, don't walk, the break through is much more civilized and they leave less burr. If the stock is smooth you can get away without center punching at all. 

The downside is you need a sharpener, hand sharpening CAN be done but you need specialized stones and it's not really satisfactory. Happily sharpeners aren't expensive, time savings, both sharpening and drilling holes will pay for a good one in no time.

Nice scroll and great railing by the way.

Frosty The Lucky.

 

 

[BillyBones]

Anvil, i missed your railing. I like that quite a lot.

I left out the word "smaller", the hole should be .015"-.020" smaller than the reamer. 

[anvil]

Thanks for the compliments! Believe it or not it was my first hand forged railing, and my most difficult railing. Its 3 flights plus a 12' balcony piece. about 80' total. Can you figure out how many forge welds are in the sample piece? All to dimension, or you are in trouble! 

I added the scroll pic because it is a good example of precision drilling in a blacksmith shop and thought there might be some other advanced smiths who might find this useful. It didn't even cross my mind to add how I handle the clamp situation. Thanks to both of you for the heads up. If anybody has a better, or different way of securing this, I'll be the first to say Thanks and add it to my bag of tricks and when I talk of this credit where the tip came from. That's what a forum is all about, a free exchange of ideas. 

As far as this thread, I drill all my holes a 64th oversize. If I miss my mark, I correct another 64th(a 32od over total). If I am over a 32od, I plug my hole and redrill.

Frosty, I pilot most everything from 1\4" and up, especially when drilling scrolls. 

What's a split bit? Lol, nope I generally use the least expensive American made bits I can find. I hand sharpen and actually break very few. I couldn't even begin to do most anything without a center punch and scribe lines for reference points. I think I'm pretty set in my ways to change now.   

 

[BillyBones]

I have done some accent spindles on wood railing but never the entire thing. 

My go to drills are Dewalt now since they have started making those pilot point drills. They are pretty sweet to use and just a center punch mark, even quite small, is enough to get them started. Unfortunately they can not be sharpened with out special tools. They are not to expensive though, about $30 - $40 for a set. In 5 years i have bought 2 sets mostly becuase of losing them or breaking not for being dull. 

[Frosty]

A split point bit doesn't require a punch mark, doesn't mean you can't or shouldn't use one, it's just not necessary in most cases. I hope the below site doesn't break the rules, I don't see any adds. I looked through a bunch of sites and don't see many decent pics or drawings. This one lays out the differences pretty well. 

https://toolspter.com/what-does-a-split-drill-bit-look-like/

The main differences where I'm concerned is they don't walk or wobble. The center point of the bit is easier to see and it's smaller so you can feel it in a center punch easily making accurate placement much easier. You can put the bit dead on a scribed intersection and drill the hole right there. With a hand drill. No punch necessary and drilling sheet often means punching will distort the part.

Seriously, try drilling a 1/2" hole in a smooth flat surface without punch nor piloting. 

You can drill an angled hole through a pipe for instance. Start the hole, gradually lean the bit as it bites and it goes. Not an acute angle of course but try it with a standard bit.

They're also less susceptible to dirt and crud on the surface though I have cobalts I use for dirty stock. Burning propane my forged pieces don't have silicate particles in the scale like coal leaves so I get better life from standard bits but way better with split tips.

They don't put as much twisting force on the stock so it's much less likely the stock will chatter making clamping easier. 

Three flutes makes them clear the hole better and run cooler.

I bought my Bowman Cobalt split point index at least 40 years ago and the only ones that aren't still going strong were lost. 

I bought a drill doctor to sharpen them when needed, hand sharpening can be done but for not much the Drill Doctor is my go to. 

Frosty The Lucky.

[JHCC]

I got a Drill Doctor (used, from HGR) a little while back, and I'm planning on reshaping a lot of my bits to split-point one of these days.

[Frosty]

Try it on a couple bits and see what you think. Standard bit have two flutes where split tip bits have three. I don't know how much difference it makes but two flutes don't clear cuttings as fast.

Frosty The Lucky.

[JHCC]

Are we talking about the same thing? I'm talking about using the Drill Doctor to reshape bits with a two-bevel chisel point (right) to have a four-bevel split point (left):

[Anachronist58]

Looks like a perfect split point to me...

[BillyBones]

Frosty, did you notice that link you gave said to not sharpen split points? Not saying it cannot be done just wondering if you caught that? 

I use an old Black Diamond drill sharpener. It will even back cut the lip. Pretty sweet machine it is. 

 

[Scott NC]

On 6/8/2022 at 12:26 PM, BillyBones said:

I had a friend years ago get a job at a machine shop. They told him on day 1 he would be running a deburring machine. They gave him one of those deburring tools. 

  Haha, shocking that is.   I worked at a place that once ran a help wanted ad that said "Can you run a hand grinder?  Want to help change the world?  Apply now!"  At least they were up front.  

  Reamers are kind of delicate.  I ruined a few of my own before I learned how to use them correctly.  

[anvil]

The only time I use a reamer in my shop is for oilite bushings inserted and reamed to fit the hinge pin on some of my hinges. I'll forge a barrel, welded or rolled, then drill it out so I can insert and compress an oilite bushing, then ream it to fit the hinge pin. A sweet hinge. All visible iron is forged and there is no sign of the bushing, And a very smooth swinging door!

I'll have to check out split point bits. Thanks for the heads up. It won't replace my center punch and scribe, however, Their primary purpose is to mark a location as opposed to creating a place for a bit to start a hole easier.