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Lathe Tool for Chamfering O.D.s and I.D.s

hepburnman

Aluminum
Joined
Feb 20, 2013
Location
NJ
I would like to know if there is a commercially available HSS or carbide-tipped lathe tool that has a 90 degree point that is good for cutting chamfers on O.D.s or I.D.s? The tools I see are 80 degrees which will cut just a 40 degree chamfer when using the cross-slide. The point should also be well re-leaved for cutting the chamfer on the I.D. without rubbing.
 
I just single-point chamfers with a boring bit using the compound at 45°. For OD, run the lathe in reverse and hit it from the other side.
 
I have a tool holder similar to this one.

https://www.mscdirect.com/product/64922545?Arg=nv

I mount it with the shank parallel to the machine centerline.
I can use it for chamfering both OD and ID with the splindle running forward.
For chamfering IDs it needs to be raised slightly above center to create some clearence.
Works good for breaking corners and you get 8 cutting edges to the insert.
It also is good for turning and facing interupted cuts because the initial impact is away from the cutting edge with the exagerated lead angle.
 
Darn, I lost what I wrote before so here goes again.........I like the idea of a tool with two 45 degree cutting sides because if I had two of these, in two different holders, I could chamfer the O.D. with the tool moving perpendicular to the work or, to chamfer the I.D., I would place the other holder with its tool, in my Aloris quick-change tool post, 90 degrees to the other setup, and now the tool would be moving on-axis with the work. Yes, I could grind my own tool, but if I wanted carbide, I do not have a set-up for this, and also, if cheap enough, a commercially-available tool will most likely be ground more accurate than I can do I can save myself the hassle. :D

McMaster-Carr only had a tool of 80 degress (40 degree sides). I have not checked MSC yet but I was placing an order with McM-C and was hoping............
 
I would like to know if there is a commercially available HSS or carbide-tipped lathe tool that has a 90 degree point that is good for cutting chamfers on O.D.s or I.D.s? The tools I see are 80 degrees which will cut just a 40 degree chamfer when using the cross-slide. The point should also be well re-leaved for cutting the chamfer on the I.D. without rubbing.

You can buy anything you want. Most of the gunsmiths and machinists here can make what you want, but why? Take a cheap threading tool and grind the relief you need (you don't even need to approach the cutting edge), but most of the tools I have are ok out of the box. Put your tool in the lathe and set the compound to 15 degrees (if you have one of those lathes that has included angle markings set it to 30 degrees). Crank in to the edge you want to chamfer (don't touch the edge, just close) with the compound. Now turn the lathe on and advance the cross slide in to cut the chamfer (you will be cutting with the right side of the threading tool). To chamfer inside, you run backwards and cut the back side of the hole. Outside chamfer, you run forward and cut outside edge.

You can buy 1/4 inch tooling, and with the toolposts they have today you can adjust the height easily. Insert boring bars can also be used, some of them are wicked small, but there is enough tip relief on a threading tool to chamfer pretty small holes.

If you are just doing holes, you can buy 90 degree chamfer tools (countersinks) which you could run in the tailstock, and they are cheap (.5" $15 delivered, Amazon).

Art
 
Thanks for the comment Artv- I am trying to avoid having to rotate my compound. This is a bit difficult on a SB 10L as there are two screws to loosen, etc. I have been using a 60 degree threading tool but "there's got to be a better way!" I'd prefer to use the advantage of my quick-change post and quickly pop in a new tool, perferrably one with a 90 degree included angle. I got alot of catchen up to you most experienced guys and time is precious!!!:)
 
Cutting with a form tool always brings the chance of chatter. That's why rotating the compound and cutting like a normal cut is better. For inside chamfers, why not use a 90° countersink?
 
I just single-point chamfers with a boring bit using the compound at 45°. For OD, run the lathe in reverse and hit it from the other side.


This is what I do. After I chamber, I go back with my sharp solid carbide boring bar and chamfer the chamber ID and the counterbore ID and then spin it all in reverse and chamfer the threads.
 
If you are dead set on using a form tool, use a 90° multi-flute chamfer tool mounted in a tool holder. Use a single flute as your form tool. When that gets dull, rotate it one flute and you have a new edge!

But to avoid potential chatter, I'd rather single point it using the compound.
 
Thanks for the comment Artv- I am trying to avoid having to rotate my compound. This is a bit difficult on a SB 10L as there are two screws to loosen, etc. I have been using a 60 degree threading tool but "there's got to be a better way!" I'd prefer to use the advantage of my quick-change post and quickly pop in a new tool, perferrably one with a 90 degree included angle. I got alot of catchen up to you most experienced guys and time is precious!!!:)

Ok, but lathes are for multiple operations, or they wouldn't come with adjustments. Make the tools that you have work. My first lathe didn't have markings on the compound, so I had to use a protractor and a wrench. If you are going to be doing single point work, you are going to accumulate all the tooling you will need, but till then use what you got. That being said, EZ Burr can probably make you a one operation tool to get 'er done.

Art
 
I'm with manual machinist on this one - leave your 90 degree tool set on center for OD's and just raise it up for bores. You'd be surprised how far above center you can cut with this method - it almost doesn't even really matter how high it is as long as the bottom edge of the cutter doesn't drag. Just eyeball it, lock it down and plunge it in.

Plus, I use the 90 degree tool for facing and chamfering (sometimes turning) and the way the tool enters and leaves the cut is a lot easier on everything than jamming a regular turning tool into it
 
I'm with manual machinist on this one - leave your 90 degree tool set on center for OD's and just raise it up for bores. You'd be surprised how far above center you can cut with this method - it almost doesn't even really matter how high it is as long as the bottom edge of the cutter doesn't drag. Just eyeball it, lock it down and plunge it in.

Plus, I use the 90 degree tool for facing and chamfering (sometimes turning) and the way the tool enters and leaves the cut is a lot easier on everything than jamming a regular turning tool into it
I agree. Another thing also is that a 90 degree 3/8 inch carbide chamfer mill can do this also. You may have to make a holder yet probably you will not have to. It cuts pretty good. Two flute.
 
I like the 90 degree tool manual machinist is recommending but I was hoping for something with a lot cheaper price than $70. On barrels I would certainly use a boring bar or Arthur R. Warner's 35 degree profile tool with the compound turned, but for more general stuff an inexpensive 90 degree tool would be the bomb. I'm surprised now that there doesnt appear to be one commercially available. Maybe a good business opportunity for someone?!
 
This is what I do. After I chamber, I go back with my sharp solid carbide boring bar and chamfer the chamber ID and the counterbore ID and then spin it all in reverse and chamfer the threads.

Before threading the barrel do you also first chamfer the tenon right at the muzzle? Is it necessary to chamfer first here before threading towards the shoulder? I guess when you do the final thread chamfer, like you mentioned (on the opposite side), with the tool moving away from the work, this would not tend to roll the thread over where it would cause jams but I guess single-point cutting it would not tend to produce a burr anyway.
 
Before threading the barrel do you also first chamfer the tenon right at the muzzle? Is it necessary to chamfer first here before threading towards the shoulder? I guess when you do the final thread chamfer, like you mentioned (on the opposite side), with the tool moving away from the work, this would not tend to roll the thread over where it would cause jams but I guess single-point cutting it would not tend to produce a burr anyway.

I don't personally. I try to save a bit of time by doing all my 45° ops at one time. I do knock off any bur on the leading thread with a file while doing my test fits though. I'd do that whether or not I was chamfering the thread first or not.
 
Before threading the barrel do you also first chamfer the tenon right at the muzzle? Is it necessary to chamfer first here before threading towards the shoulder? I guess when you do the final thread chamfer, like you mentioned (on the opposite side), with the tool moving away from the work, this would not tend to roll the thread over where it would cause jams but I guess single-point cutting it would not tend to produce a burr anyway.

I'm old school (like when there wasn't a kindergarden). Chamfer before threading or tapping. Muzzle or breech, makes no difference.

Art
 
You don't need carbide for this type of operation unless you are doing thousands of them. It doesn't get any cheaper than a $1 HSS bit (or two) with the required profile and relief ground and mounted in a quick change tool block.

FWIW, most of the time I simply use a file on the OD chamfer and my Dad's old triangular scraping tool to break the edge on IDs, unless there is a specific reason for a specific angle. Then it is usually a boring bar and compound angle adjustment.

Honestly, if you are not willing to loosen two bolts and rotate the compound to a specific angle (twenty seconds) you are never going to learn to use your machine fully. I'm as lazy as the next guy but for me this is a no-brainer in cost vs. convenience.
 
You don't need carbide for this type of operation unless you are doing thousands of them. It doesn't get any cheaper than a $1 HSS bit (or two) with the required profile and relief ground and mounted in a quick change tool block.



Honestly, if you are not willing to loosen two bolts and rotate the compound to a specific angle (twenty seconds) you are never going to learn to use your machine fully. I'm as lazy as the next guy but for me this is a no-brainer in cost vs. convenience.

I love it..... Wish I'd of said it! Willing to take the time to dial in to within .0001",,,,, unwilling to swing the compound. "There must be a better way" Evidently, you must think you're the only thinking human on the planet. This stuff goes all the way back to the dawn of the industrial revolution. There have been a few 'sharp' ol' boys, actually making semi's full of chips, from then (the 'dawn') 'till now. I hope your spindle bearings don't seize-up if you can dial in that close.
 








 
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