How to accurately bore a milling spindle on an old lathe

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How to accurately bore a milling spindle on an old lathe

This topic has 5 replies, 4 voices, and was last updated 21 August 2010 at 07:19 by Roger Hart.

Viewing 6 posts - 1 through 6 (of 6 total)

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12 August 2010 at 16:15 #54214
Roger Hart
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@rogerhart88496
I am making a milling spindle (2 inch block+2 taper rollers+centre-turned shaft) and wish to bore the shaft Morse Taper 2. My lathe is a pretty old flat-belt job and I want the taper as true to the taper roller CL as possible (and not wobbly either).

Am I better off boring the taper in the 4 jaw (set true as well as possible) or would I be better off setting up the roughly bored M2 taper in the milling spindle as a sort of pseudo-chuck using its own block and taper roller bearings and pulley and then finish boring it??

Oh, and not spending money either!

Roger H
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12 August 2010 at 16:15 #5138
Roger Hart
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@rogerhart88496
12 August 2010 at 20:11 #54224
Peter Tucker
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@petertucker86088
Hi Roger,

I would suggest boring the spindle in its own housing and bearings

Good luck.

Peter.
13 August 2010 at 09:59 #54234
jomac
Participant
@jomac
Hi Roger.

What if you brought a set of morse taper reamers, they are cheap on E/bay, and ream the shaft insitu using a properly aligned holder. And then check with a good dead centre that you know is accurate. or if you have them, a set of collets, fitted with an accurate point, or clock a piece of drill steel while this is set up in position. It probably means making some sort of jig to get everthing in line, Best of luck.

John Holloway
13 August 2010 at 17:47 #54241
John Haine
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@johnhaine32865
Another way to do this is to make a double-ended MT2 arbor – ie 2 make tapers back-to-back (assuming your lathe h/s is MT2 as well). It may be possible to do this by joining two off-the-shelf MT2 arbor blanks, but I made mine from scratch. You first chuck some 3/4 free-cutting and turn the best MT2 taper you can; then remove it from the chuck, remove the chuck, and mount the workpiece in the h/s socket by the taper, holding it with a drawbar. Now turn the second taper MT2 and also drill and tap for a drawbar.

Then bore an MT2 hole in the spindle stock material and ream it to size/finish. You then fit the double-ended arbor in the h/s, and mount your blank spindle on the end sticking out, hold it by a drawbar (ie.a bolt) and turn the outside to be concentric with the MT2 socket you just made. Sounds long-winded but it didn’t take me too long and it all worked. If I can find it I could lend you the double-ended arbor I made?

John.
21 August 2010 at 07:19 #54501
Roger Hart
Participant
@rogerhart88496
Thanks to all. Clamped block to lathe bed and did final cut using the spindle’s own bearings then used taper reamer pressed in by a flat-ended tailstock. Worked very well, max runout about 0.5 thou. One problem. Found taper reamer had cut a little too deep and had to machine 1/4 inch off the nose – lucky I had made this a bit long anyway. I have used John’s technique in past and that can work well too.

Roger
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