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View Full Version : Floating Reamer Holder for Tailstock



japcas
09-20-2011, 09:30 AM
I'd like to have a floating reamer holder for the MT3 tailstock on my lathe. Can any of you guys recommend one that you have that works well. I've looked at a couple from Brownell's and Midway USA, but they are pretty vague about what kind of reamers fit it. Just looking for some good recommendations from those of you that have them.

aboard_epsilon
09-20-2011, 09:40 AM
all my floating reamers have integral morse taper on them ..

they are all David Brown...as in tractors and Aston Martin

http://www.engineeringsupplies.co.uk/images/DBRSS1.jpg

all ther best.markj

Rustybolt
09-20-2011, 09:44 AM
Think of modifying a floating reamer holder used for screw machines and either modify your reamers(shorten them) or invest in some stub reamers.
Stub reamers can usually be had cheap at machinery auctions. Most people don't know what they are or how they're used.

JCHannum
09-20-2011, 09:53 AM
The Brownell's and Midway holders only hold chambering reamer sized shanks. Commercial holders are available in a variety of flavors, most are MT to MT.

You might take a look at Cogsdill for one manufacturer. The MT X MT holders show up on eBay pretty regularly.

Mark's reamer is an adjustable blade reamer. I have a couple of them made by Clarkson.

japcas
09-20-2011, 10:17 AM
The Brownell's and Midway holders only hold chambering reamer sized shanks. Commercial holders are available in a variety of flavors, most are MT to MT.

That's kind of what I thought. I really would like one for standard reamers, not chamber reamers.

willmac
09-20-2011, 11:18 AM
It is not too difficult to make a floating reamer holder. This is one I made:

http://i122.photobucket.com/albums/o248/moorbrook1860/DSCF2063-2.jpg

2MT at both ends

Based on a Hemingway kit design

http://www.hemingwaykits.com

gzig5
09-20-2011, 02:32 PM
That's kind of what I thought. I really would like one for standard reamers, not chamber reamers.

There is are a couple of different designs available on ebay. One of them uses ER collets and I saw another that took TG collets. I don't know if this guy is making them, but it is a start.
http://www.ebay.com/itm/Floating-Reamer-Holder-Gunsmithing-Lathe-w-ER25-Collets-and-MT3-MT4-Shanks-/290607450238?pt=BI_Tool_Work_Holding&hash=item43a98dc87e

Paul Alciatore
09-20-2011, 03:27 PM
Nothing shown here shows any of the design details or even the general idea of how these floating holders function. All of the floating holders I have seen simply have a smaller diameter stud in a larger diameter hole with some sort of loose fitting pin to transmit the rotational motion. I have always felt that this is a far from optimal solution as it is bound to transmit unbalanced forces to the tool which will try to move it off center. I would really like to see more discussion on the ways that have been used to make floating holders and the relative merits of each. Are there any designs that hold the reamer dead parallel to the lathe/tailstock axis while allowing it to move sideways to align itself with the hole?

willmac
09-20-2011, 05:08 PM
Paul-

The floating reamer I showed is much more than a 'stud in a larger diameter hole' . It allows a few degrees misalignment of the driving axis and the hole that is being reamed. It also allows a small, controlled radial misalignment whilst still providing a positive drive. This allows the reamer to truly track a bored hole. The typical use for it is in a lathe tailstock that is not as good as it used to be (my lathe for example) where a bit of wear in the tailstock barrel can cause a reamed hole to be slightly oversize or out of round without the use of the floating tool holder.

See details:

http://www.hemingwaykits.com/acatalog/Floating_Reamer_Holder.html

I can't post the drawings - that would be unfair to Hemingway.

JCHannum
09-20-2011, 05:19 PM
Hemingway does include a general arrangement drawing of the holder on their site. Not giving anything away by posting it here. The pivot plate pin drive arrangement is pretty typical of most floating reamer holders, the ball pivot point is a bit different from most, but most do incorporate some means of providing axial as well as radial "float".

http://www.hemingwaykits.com/acatalog/info_HK_2210.html

willmac
09-20-2011, 05:23 PM
OK, sorry, I didn't see that drawing on their website. I think it shows the arrangement pretty well - its a bit like a universal joint with constrained movement.

japcas
09-20-2011, 05:29 PM
We have a few at the shop where I work. I've just never seen a name on them or have any idea where they came from. They all have some age on them. We have some that are cat 50 and a couple for the lathes that fit the morse taper socket of the tailstock. Ours aren't like the type that Paul mentions but I've seen that design before. The one's at work are sort of spring loaded and allow a generous amount of movement to align the reamer with the whole. I would prefer to not have to build one, I've got more than enough projects going then to build another tool.