How was the hole in a stub reamer used in a floating holder?

JST · Aug 7, 2020

I have a bunch of stub reamers for use in the Logan bed turret. All have a hole through the shank, across on a diameter.

I found in an old machinist reference (from 1940) a comment that the hole was used in floating reamer holders. All I have been able to find has been speculation that the hole was a loose fit on a pin, so the combo of the loose fit, and sliding on the pin provided the "float".

So, is that the whole story?

Seems kinda crude, and liable to damage. Maybe it is better than I think.

Really just a curiosity issue, I have a floating holder for them.

Limy Sami · Aug 8, 2020

That's how I've seen them working back in the day (<> 50 years) on what I saw there wasn't much slack in the holders, sort of ''just enough so the tool can find find the hole'' .....so as not to cut oversize.

As for being crude? ........IMO a lot of capstan and cam auto tooling was crude ..........things like DOC & final size being set by hammering the tool in to place - etc etc.

johnoder · Aug 8, 2020

Have a drawer full of NOS .904 stubs - every one of which has a very nice .250 hole in the .750 shank. I'll suppose these were lifter bore reamers in the Chrysler plant 60 plus years ago

JST · Aug 8, 2020

The difference between that and most other floating holders I see such as those in the B&S catalog, is that it allows both a radial movement AND a "tilt". The slop in the pin hole allows the reamer to be at an angle to the spindle axis.

Most of not all the floating holders, reamer or otherwise, seem to have the radial portion only, with the tool otherwise held parallel to the spindle axis. That way the reamer or tap etc has to go straight, even if it is off-axis, and would have a tendency to correct small errors in the case of a reamer.

It seems as though that is nearly always what is wanted for a reamer. With a tap, one wants it to go down the hole straight, to not get forced off into the solid wall, and there might be some advantage to allowing it to follow a hole.

Is there any advantage to allowing the tilt as well as the radial movement with a reamer? It seems more like a problem, an opportunity for things to go wrong.

Limy Sami · Aug 8, 2020

Where's Camscan ? - he might know.

JST · Aug 9, 2020

Bump.......

No takers?

thermite · Aug 9, 2020

JST said:
Bump.......

No takers?

Not much of an "expert" here, other than what IE and Mfg MANAGERS need to know, but.. just because there WAS provision for a bit of "float" didn't mean it was meant to be required.

Much of what you are looking at was more pragmatically meant to reduce risk of grabbing and BREAKING OFF a reamer and the accompanying show-stopping of a slender-margin production run.

Scrapping the odd out-of spec finished item is always a possibilty on high throughput working.

Yah try to minimize it, but there cometh a point too much throughput loss to slower and more cautious working costs more than the value of an infrequent reject.

Just do your setup best you can. It should not present itself as a problem.

JST · Aug 10, 2020

There is no "problem", I either hold them in the soocket as-is, or cut them down if needed if they are too long with the extra shank that has the hole.

I am trying to discover how the holder actually did do the float, AND whether the algular slop was regarded as an advantage (why?) or a disadvantage.

I am asking in light of the fact that modern holders seem to have only a small radial float, and the makers appear not to be concerned about angular float.

thermite · Aug 10, 2020

JST said:
There is no "problem", I either hold them in the soocket as-is, or cut them down if needed if they are too long with the extra shank that has the hole.

I am trying to discover how the holder actually did do the float, AND whether the algular slop was regarded as an advantage (why?) or a disadvantage.

I am asking in light of the fact that modern holders seem to have only a small radial float, and the makers appear not to be concerned about angular float.

J? You are ALWAYS "asking" ....rather than utilizing.

Might I guess childless? Where wuddja even find the TIME to..

"Run what yah GOT!"

JST · Aug 10, 2020

thermite said:
J? You are ALWAYS "asking" ....rather than utilizing.

Might I guess childless? Where wuddja even find the TIME to..

"Run what yah GOT!"

Dude.........

I use the things, have no fear. Setscrews and bushings as needed, in a radial only floating holder if it seems appropriate. Or an adjustable holder. Depends on what is left after other tools are loaded.

I am curious about the old way they were used by means of the hole, just because.

Live with it, and quitcherbitchen, This is the antique machinery area and seems appropriate to see if anyone actually knows. Otherwise I could not care less about the hole, unless it gets in the way.

There is always the possibility that the old fogeys knew something that might be useful, and the old way might have an advantage. Or not.

If'n yah can't help, at least don't HINDER......

"asking not utilising?" My clients don't generally care to have their stuff posted, a lot of it is development work to end up with a patent...... Not a ton of TL work, but some. Enough parts to not do it one by one cranking, not enough to call "ox" in Ohio and get him to run them.

You got any of YOUR customers stuff to post?

thermite · Aug 10, 2020

JST said:
You got any of YOUR customers stuff to post?

LOL! "it's all AROUND you", J.

Networks. You could not "post" ANYTHING without them!

The lot of you are USING "my old customer's stuff".. to get paid, pay yer bills, communicate, and.... . would yah believe "post" ...

sfriedberg · Aug 11, 2020

thermite, If you don't know the answer to his perfectly reasonable technical question, just say so. Or try not replying at all. This is not a situation where early network engineering, hearing aids, or field gas liquification plants are relevant. And to be blunt, you have been even more wildly off-target, tangential and too-much-trouble-to-parse the last couple of months than your usual.

JST, a couple of months I ago I hunted out a bunch of old-school (like century-old) floating reamer holder articles in response to some other thread here on PM. I still have that stack of books bookmarked. When time permits this week, I will scan in a few. There is not a whole lot of sophistication in them. There's a transverse pin in the holder, smaller in diameter than the hole through the reamer shank. In some cases, the operator had to guide the reamer lead taper to the hole, there could be that much slop/flop/droop.

JST · Aug 11, 2020

Thanks, I assumed that the pin supplied the "float", but that could have been wrong. It sounded really crude, but they were different times.

I'd be interested in what the articles say, and appreciate your time digging them out (do take your time, no need to rush). Machinery history is pretty interesting, and this is the place for it.

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