11 Degree Chamfer Tool Won't Cut 38's

[Tar Heel]

I am looking for input on why my brand new 11 degree Chamfer tool will not work on a 38 caliber forcing cone. I purchased the Brownell's chamfer tool for 38-45 calibers and it cuts the 45's perfectly. When put into a 38 forcing cone, it cuts near the land/groove interface, and creates a race cut about half-way to the barrel face. It then stops cutting and rotates freely. I have applied pressure to it (real hard pull), I have cleaned the cutter, I have prayed, I have cursed, I have tried just about everything but once it makes the first little cut, it stops cutting.

The small end of the cutting head is smaller than the pilot so the pilot is not in the way or interfering in any way. The tool feels sharp. It just stops cutting and rotates after that first little cut.

I'll attache some pictures so you can see what I am talking about. I pulled like hell on the T-Handle and this is all I could get.

One barrel is a Uberti 1872 Open Top and the other is a Pietta 1873 SAA. Both in 38 SPL. The third photo is the .44-40 which chamfered perfectly with the same tool.

Suggestions?
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[Wheelguns 1961]

I have the same tool and have cut forcing cones in both calibers with mine, but looking at your pictures I don’t have an answer. It has been awhile, but if I remember correctly, the closest part towards the cylinder should cut first. Any nicks on the cutter? The only cone I couldn’t cut with mine, was a barrel with a sleeve on an lcrx. It was too hard.

[samari46]

Only suggestion I can give is that from your first two pics is that the throats are larger in some areas that the cutter will not touch. The last pic does show an excellent recut revolver barrel throat. Maybe the wrong terminology but you get my idea. Frank

[725]

not sure. I've never had that problem with mine. it's been years since I did it last, and I don't remember cutting as much as is seen in picture #3

[Der Gebirgsjager]

Without seeing the tool or seeing it in use, I'd have to re-state what appears to be the obvious, that the tool isn't contacting the work. I'd start by phoning Brownell's -- they have a whole staff of gunsmiths who are eager to talk with you on the phone (they get paid to do it) and they may have a solution for you that includes sending the tool back for examination and replacement if necessary. I've always found Brownell's to be good folks to deal with -- if a bit pricey! I like your photos, and one with the tool in place in the forcing cone might help.

[DougGuy]

If you are using the brass pilot in front of the cutter, and you load it into the bore from the frame window, is there a chance they are not going into the bore because of thread choke and the cutter cannot move forward because the pilot is stuck?

[Wheelguns 1961]

The first photo, to me, shows possibly some cone erosion, or a poorly cut cone from the factory. If you cut that one deeper it should clean up. The problem, how deep is too deep? I know that there are gauges to measure this, but you can’t really stop half way. On the second picture, is it possible that the top is already too large? That is the only thing that makes sense.

[Tar Heel]

Here is the problem. I put the tool under a microscope and WOW. The pictures show that the cutting surface has been damaged possibly by the high lands on the Uberti barrel. Uberti barrels have been known to have crystalline inclusions in them (I had one with a crater in it once) and that barrel may have damaged this cutter when I first used it. I was developing my style and may have been to aggressive on the first cut. The damage was evident under a microscope and this images show the damaged area. The "chip" looks like the crack surface of a cast iron skillet in that it is porous. Either way, it appears that I have ruined this cutter. I called Brownells and believe it or not, they are going to replace the tool for free - even though I probably damaged it.

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[Tar Heel]

Thanks for the excellent suggestions folks! All very good ideas and possibilities. Unfortunately it seems as though my lack of technique caused the problem by damaging the tool with a too aggressive first cut. Now I know. Another 100 years and I may be in the Guild!

[Tar Heel]

If you are using the brass pilot in front of the cutter, and you load it into the bore from the frame window, is there a chance they are not going into the bore because of thread choke and the cutter cannot move forward because the pilot is stuck?

Thanks Doug. The pilot was free to travel and was not causing the "depth" problem. I even thought barrel crush was involved but alas, it was not.

[Wheelguns 1961]

I am glad it all worked out for you

[country gent]

Use plenty of good cutting oil when reaming and light cuts interrupted cuts are hard on cutters. Is that cutter hardened steel or a high speed with or with out cobalt? Most cutters can be touched up with a fine by hand or sent out for a true resharpening.

[Outpost75]

Hint to others with this set, best cutting lubricant to use with these is Brownell's Do-Drill. A 16-oz. can will last the average hobbyist for years.

https://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/taps-dies/tapping-cutting-fluids/universal-do-drill-prod1120.aspx

Many of our gunsmith customers have told us this is the best product we've ever offered for tapping, drilling and cutting all types of heat-treated steels, moly and stainless. Excellent for chambering and boring jobs, a coolant for lathe, mill and shaper work – will speed production and reduce tool costs in your shop every day. Non-evaporating, does not require stream application for 99% of the jobs, it follows the tap or drill in the work. A moneysaver. We know of cases where all four holes for a mount have been drilled and tapped using DO-DRILL™, and the tap was still sharp enough for future use. With taps as high priced as they presently are, you cannot afford NOT to use it.

Big Book Catalog, Issue:71, Page:390
Big Book Catalog, Issue:71, Page:445
Big Book Catalog, Issue:71, Page:448
Big Book Catalog, Issue:71, Page:455