RPMs while chambering

S

Superman

Guest
After a recent conversation with Kiff at PT&G, I've been curious about the process others are using. When discussing the HSS vs Carbide reamers we got on the discussion of rpm's used while chambering. Dave said a carbide reamer needed to be going twice as fast as a HSS reamer for good surface finish at about 400 rpm's. I was taught to chamber as slow as your lathe would run but Kiff told me I should be running my HSS finish reamers around 200 rpm's. Are you guys going turning this fast? A freind told me Kiff was a "tool and die maker, not a rifle builder". Your thoughts please and please include a brief description of your chambering method (IE reamer with pilot the entire time, drill and prebore etc.).
 
Last edited by a moderator:
Superman said:
A freind told me Kiff was a "tool and die maker, not a rifle builder".
Click to expand...
He couldn't have given him a better compliment.

But seriously, what is that supposed to mean? "Tool Maker" means, he knows something about tooling. The guy owns a company that's made 10's of thousands of reamers. Wth do you think, he's never run one?

It depends upon how soft the barrel material is. If it's really soft, you might think intuitively that slower is better when in reality, that's not always the case.

If you don't like his advise, why don't you just try a few different speeds and see what happens for yourself. Then you'll know.
 
Reaming speed

I have a friend who has always advised me to ream at a higher speed. I just can't bring myself to do it..I have never ventured past 100 RPM and that makes me nervous. I prefer 45 -70, and get very nice finishes..A larger bore where chip clearance is better may be OK, but a .22 ??..I see snapped of reamers and ruined barrels..
Jerry
 
4Mesh said:
He couldn't have given him a better compliment.

But seriously, what is that supposed to mean? "Tool Maker" means, he knows something about tooling. The guy owns a company that's made 10's of thousands of reamers. Wth do you think, he's never run one?

It depends upon how soft the barrel material is. If it's really soft, you might think intuitively that slower is better when in reality, that's not always the case.

If you don't like his advise, why don't you just try a few different speeds and see what happens for yourself. Then you'll know.
Click to expand...

Yeah, he IS a tool maker, doesn't mean he'd be the end all on rifle chambering. It's like that guy that makes some of the most incredible guitars in the world yet he can't play one like Hendrix.

I don't try it for myself because barrels are expensive and have quite a wait for a replacement.
 
Jerry Keefer said:
I have a friend who has always advised me to ream at a higher speed. I just can't bring myself to do it..I have never ventured past 100 RPM and that makes me nervous. I prefer 45 -70, and get very nice finishes..A larger bore where chip clearance is better may be OK, but a .22 ??..I see snapped of reamers and ruined barrels..
Jerry
Click to expand...

I've been chambering everything at 70 RPM's and that's worked for me but I'm still breathing so I try and continue learning.
 
poor anology.....
i guitar builder vs player...would be a rifle builder vs a shooter ...the buider vs the end user...we dont have that case here.
what we have is a tool maker and the tool user........he did not tell you how to set up the bbl nor how to fit and thread stuff...he just said the tool he made works best at a certain rpm....
he built the tool, and he knows materials.....

just something to consider....
mike in co
Superman said:
Yeah, he IS a tool maker, doesn't mean he'd be the end all on rifle chambering. It's like that guy that makes some of the most incredible guitars in the world yet he can't play one like Hendrix.

I don't try it for myself because barrels are expensive and have quite a wait for a replacement.
Click to expand...
 
I have to agree with mike here, and 4mesh. The toolmaker must understand his tooling better than the end user, but that has little to do with "playing." The best driver/golfer/shooter/ballplayer doesn't really have much to say to the toolmaker, or the guys building the equipment. IMO David Kiff understands his tooling.

Spec'ing or building rifles is a largely unrelated science. Not saying Dave isn't good at spec or build either, just that for him to make good reamers he MUST know how to use them.

al
 
While I can respect you guys trying to defend Kiff's honor here it really isn't necessary, I think the man walks on water too. BUT, what I'd really appreciate is you answering the question. This ain't about Kiff, or what my friend thinks of Kiff's area of expertise OR guitar players.

I asked what kind of speeds you guys were spinning the tubes and thus far only ONE person has commented on that.

So let's forget about all that other nonsense and discuss something of interest.
What speed do you chamber at? What chamber method are you using? What type of reamer are you using (HSS or Carb)?
 
Superman said:
While I can respect you guys trying to defend Kiff's honor here it really isn't necessary, I think the man walks on water too. BUT, what I'd really appreciate is you answering the question. This ain't about Kiff, or what my friend thinks of Kiff's area of expertise OR guitar players.

I asked what kind of speeds you guys were spinning the tubes and thus far only ONE person has commented on that.

So let's forget about all that other nonsense and discuss something of interest.
What speed do you chamber at? What chamber method are you using? What type of reamer are you using (HSS or Carb)?
Click to expand...

spot on
 
Superman said:
I asked what kind of speeds you guys were spinning the tubes and thus far only ONE person has commented on that.
Click to expand...
I said it depends on the barrel material, and the tool, but I guess I'm supposed to give a speed that works regardless of all the conditions... The machine itself will also influence what speed is best, and so far, we know nothing about what barrel material, what bore size, what lathe you're using, what speeds it will do even if we do want to change them, and we don't know how you've chucked it up. Hmmm, let's make suggestions based upon on all that misinformation. :p

I don't try it for myself because barrels are expensive and have quite a wait for a replacement.
Click to expand...
So test on the one that you're taking off. What's the big deal. You were already given a suggested speed by the guy who makes the tools, and you won't listen to him. Now you ask here and are not hearing what you want so you won't listen again. You refuse to try on your own cause you might make a mistake. So what happens if I tell you a speed? Sounds to me like you're not going to try it anyway huh? So what do you care?

So let's forget about all that other nonsense and discuss something of interest.
What speed do you chamber at?
Click to expand...
100-225sfm, but for me it depends on what material, the tool, how sharp it is, many things. I decide that when I chamber and I'm not afraid to try something just cause it might be wrong. If it is, I'll fix it, just like all the other folks here. Wrong speed? ok, then find the right speed. Anyone else here will say the same. New reamer? Maybe they go a bit slower. As the reamer dulls, they speed up. In case you didn't notice yet, there is no one answer to your questions.

What chamber method are you using?
Click to expand...
My own. The barrel is in a chuck.
What type of reamer are you using (HSS or Carb)?
Click to expand...
Virtually no one here uses carbide reamers. Those who do will tell you they need to go faster, but then, everyone who deals with tooling has already found that to be universally true. Most guys here are looking for nice jobs, not fast ones. So, regardless if it's chamber reaming, or general turning on the barrel, many use hss tools. Its cause they don't have to go so fast and can still do a nice job. Carbide going slow tends to rip the material. Hss does not.
 
4mesh, I think there is a reading comprehension problem. I did not ask you to tell me how to do MY work, I'm asking how YOU do YOUR work. If you want to volunteer the type of bbl steel and whatever other pertinent information is available, do so. No one is getting anything from your condescending attitude so keep that info to yourself.
 
My attitude isn't any different than yours, read back some.

As to reading comprehension, yea there seems to be a problem but it's not mine. I answered all your questions above. How much detail do you want? And again, you still have not told anyone what your working with, but here you are asking for someone to give you answers. I don't get it.

US Barrel makers more than likely will be using Crucible 416R. It doesn't cut the same as stainless from the EU, and it will cut differently depending upon what processes it has undergone while at the barrel maker. Most here will probably agree that they see differences from brand to brand. Maybe only subtle ones, but differences.

In the case of one barrel I did which was from the EU, I cut that one at >400rpms w/hss. (might have gone >600 iirc, it's been a long time) That would almost certainly not work on something like a Kreiger or Shilen. I've done Blackstar barrels that were very soft also. Those had to go faster. Again, hss. I've never run nor seen run a Kreiger at 200rpms or higher.

And, I'm done typing cause you don't really want the answer to your question anyway. Refer above to the statement where I said you're not going to try anything anyone suggests anyway.
 
I guess I agree with 4mesh here. I did a CM barrel in 250-3000 this weekend. I use HSS rather than carbide as I get a better finish. I did mine at 500RPM. I do mine in the headstock with a cathead on each end of the headstock. I drill and taper bore leaving very little to ream. I think you would really have to phuque up to break a reamer. I use trans sultex, but when it's gone I guess I will use something else as I have been told that it is no longer available.
Butch
 
4mesh, it doesn't matter what kind of barrel I'm using, I asked what YOU guys were doing. You still don't get that. Butch was able to offer exactly what I was asking for. HSS reamer in a chrome molly barrel at 500 rpms. He also mentioned his holding method, the caliber, and the cartridge he was chambering. I'd venture that Butch probably wouldn't run that fast with a 416SS barrel.
 
I use the same speed for 416R. If I have a Rigby diameter case, Ultra mag, or any large diameter case I will go 400-450RPM. 416R cuts like butter. I only work for myself and don't ask a lot of my reamers. They don't have to cut much material and when I'm done I clean them and put a light coat of oil on it before putting it back in the plastic sleeve.

Let me add this. I do not know what Dave recommends and haven't asked him. I did tool and die work for about 8-10yrs and also did a lot of tool grinding.

Butch
 
Last edited:
Butch Lambert said:
I guess I agree with 4mesh here. I did a CM barrel in 250-3000 this weekend. I use HSS rather than carbide as I get a better finish. I did mine at 500RPM. I do mine in the headstock with a cathead on each end of the headstock. I drill and taper bore leaving very little to ream. I think you would really have to phuque up to break a reamer. I use trans sultex, but when it's gone I guess I will use something else as I have been told that it is no longer available.
Butch
Click to expand...

Butch, you likely already know this, but Dave lists several suitable cutting oils on the PTG site.
 
Thanks,
I have been to his website numerous times, but wasn't aware of the cutting oil recommendations.
I will have to check it out.
Butch
 
For the new guys to chambering, not the experienced pros:

Back to basics, or what we old worn out machinists had pounded into our heads by the master machinists: A simple formula well over 100 years old:

For high speed steel tooling: 4 times the cutting speed of the material divided by the diameter of the workpiece gives RPM

So for 4140 at about 50 SFPM cutting speed with a 1/2" diameter reamer we have:




I'll be darned!





400 RPM


Must be magic.

Assuming properly ground sharp tooling, good sturdy setup, proper coolant/lubricant to both cool the cut and to lubricate the tooling.

You can push the RPM higher with good tooling and a sturdy machine & setup, provided you have adequate cooling/lubrication

Carbide doubles or triples the RPM due to the high cutting speed in SFPM.
 
You must log in or register to reply here.
Back
Top