Audel's Machinist book and Draw Out Nuts

ThunderDog

ThunderDog

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Hi all,

I was just paroozing through Audel's Machinist book and noticed the section on arbors. The topic of withdrawal of an arbor from a taper was of particular interest to me. For me, removing the arbors from the Atlas horizontal mill can be challenging and I really don't like the tap-tap-tappee of a brass hammer.

Anyway, the attached picture I've included just was not making sense. I guess I'm having a hard time visualizing the clutch and operation of it. Does anybody have an actual example?

20170416_112537.jpg
 
I'm thinking it's nothing other than a pin acting as a keyway.
My horizontal does'nt have it nor do I have any arbors that are threaded there. So tap tap it is.
You are driving it out from the back of the spindle....right?
 
Yup, my current method is to loosen the drawbar a few turns and then tap on the end of the drawbar with a chunk of brass. I don't like that way as I feel it will prematurely ruin the threads or worse the taper. I suppose a piece of steel with a brass piece screwed on the end could be made as a removal tool.
 
It appears to me that what they are referring to as a clutch is actually just a drive pin or drive lug sticking out of the arbor. I have a taper adapter here that adapts some AT collets to the MT3 spindle on my lathe. That adapter has an internal pin sticking out into its internal taper and provides a positive drive for the collets, which have a small keyway cut into each one.
 
terrywerm said:
It appears to me that what they are referring to as a clutch is actually just a drive pin or drive lug sticking out of the arbor. I have a taper adapter here that adapts some AT collets to the MT3 spindle on my lathe. That adapter has an internal pin sticking out into its internal taper and provides a positive drive for the collets, which have a small keyway cut into each one.
Click to expand...
Collets are supposed to seat and drive on their tapers. The pin is for keeping the collet from spinning while installing and removing it, nothing else. If it is used as a "drive pin", it will soon turn into a "shear pin."
 
Well here I go again looking at it from a different side. The picture looks like a low taper maybe a morse on the shaft at the drive head which has a threaded section right at the head where a nut is used to remove the taper. Instead of a bearing on the outboard end its using a center into the end of the shaft to hold the arbor into the head.
I would guess this is much before the NST 30, 40, 50 tapers.
Heck I was trained to back off the draw bar a turn or two then tap the end of the bar with a hammer to loosen the tool holder / arbor. The draw bars threads are much softer then the holder / arbor and if anything was going to wear out it will be the one.
Also when using a puller to get a gear off the shaft I was told to tighten up the puller then tap the end of the screw rather then just keep tightening the screw.

Jim
 
That is describing a special made arbor with external threads on the wide end for the draw out nut. I had one (B&S 9 I think also a face mill, not an arbor), that had threads there, and it never made any sense until now. I thought maybe it was for a big slitting saw or something.

The next pic is just showing another way to support the end of an arbor, besides a bearing. I might try something like that, my Van Norman overarm support has a hole for like a 1/2 end, but my two arbors have a 1", and a 1&1/2" shafts and ends.
 
I have that book. That's a good book. I also have a Atlas horizontal mill. My draw bar has a 2-1/2" long hex head. I just loosen it up a couple of turns with an old 1/2" deep socket.
I remove the ratchet & leave the socket on the draw bar & try to give the end of the socket a good clock with a hammer to free it with one hit.
Unfortunately, most of the time it takes 2 or 3 hits if I'm lucky. The wall behind the machine limits me a little. I don't think it's good for the bearings.
Neither of the 2 arbors I have (7/8" & 1"), have a draw out thread on them like in the picture. I suppose one could be custom made along with
a spindle thread protector. Are you thinking of making one like that?
I hope we're talking about the same thing.

Todd K.
 
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