Cutting a taper?

Laverda · Feb 16, 2018

I need to put a taper on the end of a shaft. The taper is .0015" for a distance of 1/2" so I would need to set the compound to .0859 degrees. How do I set my compound for such a small angle????

muckalee · Feb 16, 2018

Using a dial indicator works for me. If you have none, try using shim stock.

crazygoat · Feb 16, 2018

Is .0015 a typo? +/_ .0005?

Demon69 · Feb 16, 2018

Laverda said:
I need to put a taper on the end of a shaft. The taper is .0015" for a distance of 1/2" so I would need to set the compound to .0859 degrees. How do I set my compound for such a small angle????

Joe Pieczynski is always a good watch, enjoy.

Laverda · Feb 16, 2018

Yes it really does need to be a .0015" taper over 1/2". It is a main shaft that is pressed in to a flywheel. At the end of the taper is a shoulder. As for the tolerance, as I am reverse engineering a 90 year old part, who knows. If the taper is too small it won't grab before it hits the shoulder. The hole in the flywheel also has the same .0015" taper. A couple tenths big will be OK as the flywheel hole will stretch a little bit. Too big and it could crack the iron flywheel. Taper should start to grab when about 1/2 the way into the flywheel. Measuring two flywheels the holes are exactly the same diameter. Measuring two shafts, they got them to within .0002" of each other. That's pretty accurate machining for doing this in 1928 on machines that had probably been run into the ground in England during WWI. As for the video, thank you!

EDIT: Forgot to mention, shafts will be case hardened and ground before the taper is done (shafts run in bronze bushings). Maybe I should just stone the taper in? Grind the big diameter and do the last bit by hand with a stone.

juergenwt · Feb 16, 2018

Laverda said:
I need to put a taper on the end of a shaft. The taper is .0015" for a distance of 1/2" so I would need to set the compound to .0859 degrees. How do I set my compound for such a small angle????

I am putting my money on a 1/2"dia straight shaft.

iwananew10K · Feb 16, 2018

Sound like a lick with a file territory.

MichaelP · Feb 16, 2018

Perhaps, shrink fit will do?

Limy Sami · Feb 16, 2018

At 90 years old, possibility of clappo machinery etc etc and British ? pound to a pinch of saffron, that was a lick with a file job, .........more than likely by nothing more than a skilled ''run of the mill'' turner.
Generally speaking, unless it's ''exotic'' or very high precision, don't overthink old machinery, ...you'll drive yourself round the bend ;-)

Derek Smalls · Feb 16, 2018

Demon73 said:
Joe Pieczynski is always a good watch, enjoy.

I'm glad this Pieczynski guy is so sure of himself, but I see some major problems with this method. Errors stack up, especially when they are never accounted for in the first place! Also, he offers no way to confirm the results in the part itself by inspection.
Yeah, argue with the inspector that the taper is right, not because you measured it, but because Pieczynski said it's so! :nutter:

Demon69 · Feb 16, 2018

Derek Smalls said:
I'm glad this Pieczynski guy is so sure of himself, but I see some major problems with this method. Errors stack up, especially when they are never accounted for in the first place! Also, he offers no way to confirm the results in the part itself by inspection.
Yeah, argue with the inspector that the taper is right, not because you measured it, but because Pieczynski said it's so!

Lol, yeah I could just imagine

Im racked with cold now so its all a cough ridden blur. IIRC from watching it before, its just basic trig and being aware of backlash, but he indicates off the TS quill, plenty of room for errors there. Im sure I thought why not just turn the OD an indicate off o that. Regardless still got to measure what youve got in some way to be confident with the result.

johnoder · Feb 16, 2018

Good "tenth" indicator - cylinder square sitting on gage blocks so its actually on spindle centerline - any shallow angle is a snap as far as concept. The usual real world issues such as imperfect compound slide detract

Limy Sami · Feb 16, 2018

I forgot to mention IMO that tapers only there to help get the shaft started right and avoid a sharp end - (even a 45 bevel will do it) ''broaching'' the hole oversize instead of really gripping on the shaft.

To the OP

Out of interest, what dia is the shaft and length of hub locating on it?

Joe Pie · Sep 21, 2018

Hey Derek. Nice comment. Gutless, but entertaining.

thermite · Sep 21, 2018

Laverda said:
I need to put a taper on the end of a shaft. The taper is .0015" for a distance of 1/2" so I would need to set the compound to .0859 degrees. How do I set my compound for such a small angle????

This was fair common on farm equipment, one-lung IC engines etc, but at about 3/4" to 1" run, and a good deal steeper. Mostly, we filed the shoulder back a tad, then cleaned them up, checked with filthy black grease, which was always handy, whether anyone was wealthy enough to own a tiny tube of Prussian blue or no.

IOW - it is done with a measure of "patience", a large ration of "give-a-damn", and whatever sort of "metrology" one can commandeer, if even as simple as grease, lipstick, high-spot.

Check, wipe, try again, repeat.

Not much required in the way of lathes and stuff.

You are down into the zone where the part with the bore in it very well WILL move into accommodation. Just don't ask it to do staircase steps or too much of it. When it fits well enough to "stick", sits true, sits tight, it IS right.

Tony Quiring · Sep 21, 2018

Laverda said:
I need to put a taper on the end of a shaft. The taper is .0015" for a distance of 1/2" so I would need to set the compound to .0859 degrees. How do I set my compound for such a small angle????

Just make a straight shaft with an atxxx...

Can the part be made between centers?

Shifting of tail stock makes easy to sneak op on it.

Practice with scrap until correct.

Sent from my SAMSUNG-SM-G930A using Tapatalk

Derek Smalls · Oct 6, 2018

Joe Pie said:
Hey Derek. Nice comment. Gutless, but entertaining.

Hey Joe. I'm glad you were entertained, but I'm not sure why you would call my comment gutless??? I simply referenced some of the flaws I noticed in the method you presented. First, your method's total dependence on the geometry of the machine(tail stock quill) as well as the lead of both the cross slide and compound screws to be perfect. Second, and most important, your complete lack of a suitable inspection of the part itself to confirm the angle of the taper actually produced.
I'm sure your method would get you close, probably close enough for many classes of work, but without actually measuring or gageing the produced taper, there is no way to say if the part is in tolerance or not. To say this method produces "amazing" accuracy just doesn't cut it for me, nor any inspector I've known. Sorry.

thermite · Oct 7, 2018

Joe Pie said:
Hey Derek. Nice comment. Gutless, but entertaining.

Method was entertaining, but also "gutless". Where was the gaging derived from again?

Billtodd · Oct 8, 2018

Just for interest:

For shallow angles I'd normally set up the taper attachment (hlv-h) and set it using the dro as a virtual sine bar .(Works really well)

To set the Top slide angle accurately I have cobbled together a test bar , sine bar , 123 block , spacers and a gauge pin , so that I can set the angle of the topslide V way to match the sine bar.

(looking for picture of above lash up)

Cutting a taper?

Cast Iron

Cast Iron

Stainless

Titanium

Cast Iron

Stainless

Diamond

Titanium

Diamond

Stainless

Titanium

Diamond

Attachments

Diamond

Plastic

Diamond

Titanium

Stainless

Diamond

Titanium

Similar threads