Chamber reamer in the carriage?

S

Superman

Guest
Was wondering about something and I thought some of you old salty dogs could answer the question for me.

What would be wrong with holding a floating reamer holder in the tool post? For example, pick your favorite floating reamer holder and morse taper contour, insert in MT tool holder, center tool to bore, and chamber. I have a DRO, why not use it? I can precisely measure chamber depth of cut this way. Since my lathe is new, the tailstock is a little tall. I figure holding in the tool post and using the benefits and smooth operation of the carriage makes sense.

Is there a reason NOT to do this?
 
I thought about this also. A couple things come to mind. Most crosslides have some backlash this would have to be eliminated by locking down the crosslide. I like the tool feedback I get by pushing the reamer with the tailstock while holding the reamer holder with my other hand, Im not sure to it would be as easy to "feel" while advancing the carriage. I guess advancing the tool with the compound would be an option but it would not utilize your DRO
 
but wouldn't you need to dial in the coumpond to make sure it was straight to the bore.....not just those degree marks they come with ???....when done it should be fine.
 
I thought I read where Chad was doing this.. I have tried it..I much prefer the tail stock..
Jerry
 
I have a set of barrels that, I believe, were chambered with a reamer that was pushed by a dead center that was held in a tool holder, and dialed in off the chuck. All of the chambers are of very high quality, and I can interchange brass between all barrels, which were cut with my reamer. None of these barrels required much break in, and their rifling marks bullets perfectly evenly. Obviously your idea isn't worth a hoot. ;-)
 
I'm going to do it of the tool post, what led me to it was Chad and that when I run my tail stock spindle out I get .004 of drop per 2 in of travel and whenever I return to position with the tail stock and tighten it never quite returns to where I started and I'm not skilled enough to deal with it. I put a ground rod in a tool holder and ran the carriage back and forth while indicating the rod and I could get no measurable movement that was out of wack so I kinda thought that that might be the most accurate way for me in my set up to push a reamer. Could be I just don't know any better yet!
 
Tailstocks are for doing general purpose work that is too long to be supported by the headstock. They are not, nor were they ever intended to do high accuracy work.

A lot of high accuracy CNC's do not even have tailstocks on them.

Over the years machinists have used a tailstock for everything except what they were designed for, that's why a used lathe will usually have a tailstock that has been beat to death, and now worthless for shaft work.

If your carriage is not accurate, you are fooling yourself thinking that your tailstock is.

Morse Tapers should be restricted to drill presses.
 
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Using Carriage instead of tail stock..

I have read over the years of other doing this.
I ream using the tailstock. But I use the carriage as a fixed tail stock stop.
I lock the carriage down.
This gives me a relational starting point when I return to reaming after withdrawing and checking for chips and chip weld.

With my lathe I would be worried about latteral wiplash with my carriage.

Nat Lambeth
 
I've not pushed a reamer with the carriage, but I've thought about it. I understand why Chad does it that way. Chad's setup and mine are quite different. My carriage moves along a test bar in the chuck within 0.0005" which is plenty good enough. But with the floating pusher, the feel it gives me, and the precise feeding of the tail stock feed screw to control torque, I've not been motivated to try it. I also use the carriage as a tailstock stop.

The process improvement I want to make next is muzzle flush coolant during chambering.

Fitch
 
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