carbide finishing reamer

S

skeetlee

Active member
Anyone here using a carbide finishing reamer? I use a carbide roughing reamer sometimes and I really like it. I need to order myself a new ppc reamer and im thinking I may order it in carbide. Any down side, or experience one could share before I decide? thanks Lee
 
Carbide Reamers

First, Carbide is extremely hard and brittle. It is designed to be run at high cutting speed and feed. To do so you need a flood/flush coolant. You also have to support it rigidly. Most small gun shops are not equipped to run carbide. If you don't run it as designed it will chip and break. Reamers made of tool steel are much less expensive and cut at lower speeds and much more durable.

I have and use a high pressure coolant chambering system and have several reamers that have 3000 chambers cut with out a regrind or sharpening. I cut most small chambers at 55-70 RPMS and 75 pounds of flush, most medium chambers 100-175 RPMs, at 35-50 pounds of flush, and large chambers at 175-225 RPMs at 25-45 pounds of flush. With large chambers there is much more volume coolant moving through.

Never found a need for Carbide reamers in a small non CNC shop.

Nat Lambeth
 
Rustystud said:
I have and use a high pressure coolant chambering system and have several reamers that have 3000 chambers cut with out a regrind or sharpening.
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Now that's some gosh darned incredible tool life for HSS....

I judge acceptable tool life by calculating the amount of time spent in a cut. In example - 3000 cuts at 1 second per cut equals 50 minutes of cut time. 3000 cuts at 10 seconds per cut equals 8.33 hours of cutting. I'm usually satisfied with about an hour of light finishing cut time out of HSS cutting a carbon steel.
 
I haven't ever had any issues with chipping or not using an oil flush system as of yet with my carbide roughing reamer. Actually it has performed flawlessly. I have however had a HSS reamer with a bad spot or ding or whatever in the heck caused a flaw give me grief. More than once.

I have a real fine diamond file that I can run very lightly down the flute, and it usually cleans up.

I guess im not sure I will spend the extra cash this go around. I drill and bore, then i use the carbide roughing reamer. So my finish reamer isn't cutting much at all really. I just thought maybe carbide reamers were more widely used?
thanks for the replies. Lee
 
You'll also need pilots to fit the carbide reamer. The ones for HSS reamers won't fit the carbide reamer. I've used a few carbide reamers, but they were all customer supplied and customer owned. I stick with HSS and don't see the need for carbide reamers. Nat cuts a lot more chambers than I ever did.
 
I was looking at my 6ppc roughing carbide reamer last night and a couple things really dawned on me. The carbide reamer I have has 3 flutes instead of 5 or 6 like a HSS reamer. The carbide reamer also has rather large oil flutes, that would allow cutting oil from a flush system to easily pass through and around the reamer. I would also think that the 3 flute design would allow for more room to discard the metal shavings. Basically this reamer looks like the ideal reamer for a guy using a flush system.
Butch is correct about the bushings. PTG must make two different sizes of bushings just for their carbide reamers. I ordered a .2368 bushing a few weeks ago and the bushing I received had spiral flutes " mine has straight" and the spiral fluted bushing was to small internally to slide over my reamer shank.
 
Skeet, unless you are planning on doing a lot of barrels in a short period of time and getting "factory", mediocre, results stay with HSS reamers.
 
I use carbide reamers provided by one customer. 7.62X51, 300 Win Mag and 338 Lapua. Total barrels chambered around 700. I have never had a problem with either the 7.62 or Lapua reamers. As a matter of fact the current 7.62 reamers cuts a nicer throat than any reamer I've ever used. The Win Mag on the other hand has always been trouble, multiple reamers. I've never been satisfied with the end results in that caliber. Even with reasonably good results I would order coated HS reamers. I get 60-120 chambers out of a coated reamer. No need to go carbide. BTW JGS carbide reamers use standard bushing.

Dave
 
I have watched exactly once a carbide PPC reamer used to chamber a barrel. I guess I am now an expert. The lathe was run about 150rpm. It cut a smooth finish concentric chamber. I went ahead and ordered one from JGS. They cost about $300.00. One thing I may be able to add constructively to this discussion concerns the cir clips used to attach the bushings to the reamer. This carbide reamer uses these tiny clips instead of a screw. I suspect this is due to possible difficulty in threading carbide. My point is they look really easy to drop into the chip pan or launch themselves into the ether when removed or attached. I ordered a few spares with the reamer. I also have a question for others with more experience then I: I want to re chamber some old barrels. When I do this I usually cut off all of the old chamber and start anew. I am worried that carbon from shooting may have embedded it self into the steel and may dull a HSS reamer. Do you think a carbide reamer may work better in this case? Thanks. Tim
 
Tim Oltersdorf said:
I have watched exactly once a carbide PPC reamer used to chamber a barrel. I guess I am now an expert. The lathe was run about 150rpm. It cut a smooth finish concentric chamber. I went ahead and ordered one from JGS. They cost about $300.00. One thing I may be able to add constructively to this discussion concerns the cir clips used to attach the bushings to the reamer. This carbide reamer uses these tiny clips instead of a screw. I suspect this is due to possible difficulty in threading carbide. My point is they look really easy to drop into the chip pan or launch themselves into the ether when removed or attached. I ordered a few spares with the reamer. I also have a question for others with more experience then I: I want to re chamber some old barrels. When I do this I usually cut off all of the old chamber and start anew. I am worried that carbon from shooting may have embedded it self into the steel and may dull a HSS reamer. Do you think a carbide reamer may work better in this case? Thanks. Tim
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Carbon won't faze either of them.
 
not so sure about that you might want to section in front of chamber and do a rc test and it will not hurt carbide but steel is another story....
 
I am with George

I moved last year and in prep for that I chambered a group of barrels. I also had done some setbacks on several barrels. When I moved and got back to shooting I found that my reamer was worn on the leading edge of the neck. Since I only cut a few thousandths with my finish reamer I believe it was the set back barrels that were just too hard and or had some carbon in the neck area. This caused a pinch on the bullet and they would not shoot well. I studied the problem, had reamers reground to new specs and bought a carbide reamer to do set backs. Before you discount what I say, I drill the chamber with a twist drill, I then drill, the chamber with a special piloted drill made by JGS which includes the neck and the cone I then true the chamber by taper boring the chamber, then ream. Sounds like a lot but it really goes quickly. I only ream maybe .010 on the diameter with the reamer. The finishes are great, and centered. But My reamer did ware right on the end, I now have back up reamers and a carbide.

By the way I am finding more reasons to set back a barrel these days, making a fire forming gun, utilizing barrels for hunting guns or prairie dog rigs, making chamber gauges, more than I use to think about.

Ralph
 
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