Reamer holder

Casull

Casull

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Yukon Territory
Hi all,
I am just starting to make a reamer holder. I have an MT2 mandrel that I am going to thread and make an end and holder for. Any input here on holders you guys use and have made or bought? Any tips before I go farther into this? I am unsure if I should thread the mandrel to 1" and fit an end or say thread it 1/2" with a shoulder and so on. It might not matter at all, just looking for input.
Thanks,
Rob
 
for the money I would pick up a floating reamer holder.
it lets the pilot stay true to the bore and helps prevent the possibility of a oval chamber and is easier to set up.
 
Camk said:
for the money I would pick up a floating reamer holder.
it lets the pilot stay true to the bore and helps prevent the possibility of a oval chamber and is easier to set up.
Click to expand...

How timely - I am presently looking for a floating reamer holder. Can you suggest any sources?
 
I'd go with the 1/2" option. I use a Clymer floater, there are others, and they can be made, as Casull is doing.
 
The holder I am making will allow the reamer to "float", that is the idea.
That one pictured on McD's link is very different than what I had envisioned. I was planning something like the Clymer or Pacific Tool & Gauge floating type. This is a different idea though and that is good.
 
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Every floating holder I've seen, which also acts as a driver (like the Clymer), does not allow the reamer to float eccentrically. The holder as used by Mike Bryant is a holder only and does not drive the reamer. It allows the reamer shank to float. As a holder, it just keeps the reamer in approximate position and keeps it from falling down when withdrawn. I think it's a pretty good system. An addition to the Bryant holder which helps in retaining the reamer is an "O" ring in side the holder. The o-ring does influence the reamer somewhat but still allows some float while making insertion of the reamer into the barrel a little easier. Regards, Bill.
 
Depending on how a Clymer is adjusted, it'll let the reamer float just about every which way. But depending on a floating reamer holder to make up for poor setup is a really bad idea. If the barrel is properly indicated in, and the tailstock aligned, the reamer holder should have very little compensation to do.
 
I make my own spade bits for chambering; they are center drilled at the back and have an integral pilot in the front . In use the barrel is driven by the lathe chuck gripping the muzzle and the breach end in a steady rest. The reamer "floats between the pilot in the bore and the tail stock center at the back and I keep it from turning with a cresent wrench against the lathe bed. I remove the bulk of the metal with twist drills and leave .020 or more to be reamed out.
It may be crude but it works and costs only time.

cheers mooncoon
 
At a glance, the Clymer holder would appear to be able to float in an eccentric manner and one could be forgiven for believing this to be the case. In fact, when under load, any eccentric movement is inhibited. The Clymer uses two flat surfaces connected by screws in over sized holes. When not under load, the two pieces can move easily in all directions. When put under load however, the screws move to the "bottom" of the oversized holes and are held there by the load and the radius of the hole. The interaction between the screw and the hole establishes the center and the location at which the reamer will be held. If this center co-incides with the axis of the lathe, all will be well. I've used a Clymer holder quite a bit in the past and found it to work quite well but it was not perfect.
Generally speaking, if you do not take care to set the barrel up to run true, it matters not what kind of reamer holder is used; the odds are against a perfect job. Various reamer holding methods are used to compensate for very minor deficiencies in the setup. Regards, Bill.
 
Bill,
Is there a holder design you would recommend over the "floating" Clymer type?
I have a new mandrel and have not done anything with it yet. Another member has offered a Clymer type at $60, so price is not bad. Your thoughts Bill?
I am aware that proper setup is the key, I am hoping for the best possible holder though as I have to get it anyway. To this point I have been setting the barrels up taking time there and using a center in the tailstock and a wrench for slow chamber cutting.
 
I am not Bill but here is a picture of the holder I made... really simple to do. I copied the concept from Mike Bryants website.

I first drill the chamber undersize and then bore the body diameter of the chamber undersize so the reamer will start cutting about half way in. The taper of the reamer finishes it nicely.

reamer%20holder.JPG
 
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Casull,
The holder shown by Dennis probably works as well as any and, in some respects, better. It is, in essence, a holder only and not a driver. In fact, it holds only very loosely and provides a means to push the reamer. You could take your mandrel and face it smooth on the front then fit a short sleeve to the front end to produce the recess that actually holds the reamer. The only drawback at all to this is that it is often better to have the reamer centered positively at the rear when starting the reamer. I accomplish this by using a small ball which fits into the center at the rear of the reamer and is centered by the center drilled inside the recess of the holder. By the way, mine is set up so the base of the reamer is pushed by the mandrel. I don't know that it makes any difference as long as the surface against which the reamer rests is smooth and flat (apart from the center hole). Once the chamber is well started, I can leave the ball out and the tail end of the reamer can move. If the barrel bore is curved at all, the tail end of the reamer must, at some point, be able to move around. If it is held to center while the pilot describes a circle (as it will with the crooked bore scenario) a slightly out of round chamber will result. Most barrels have a certain amount of bore "wandering" going on even if it is miniscule. It is possible to set up a barrel so that portion which will receive the chamber is straight in most cases. In those cases where some divergence of the bore exists though; a hlder like the one Dennis has shown will give the best chance of an aligned, round chamber. Regards, Bill.
 
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