Thread: Turning Tapers without adjusting Tailstock

Hi Bruce,
They are a very good idea. I think MrPete (tubal cain) uses some in some of his video's, but i have never investigated further.
Is it .006"/foot per side or over all?
What happens when the part you are machining warms up, is there a chance of it coming loose?
I guess an arbor press would be the best way to put parts on and off the mandrels, but failing that a copper or deadblow hammer would work just as well.
Thanks for sharing

Cheers,
Ew

Originally Posted by Ueee

Hi Bruce,
They are a very good idea. I think MrPete (tubal cain) uses some in some of his video's, but i have never investigated further.
Is it .006"/foot per side or over all?
What happens when the part you are machining warms up, is there a chance of it coming loose?
I guess an arbor press would be the best way to put parts on and off the mandrels, but failing that a copper or deadblow hammer would work just as well.
Thanks for sharing

Cheers,
Ew

Ewan
Thanks for your interest.
The .006" per foot is on diameter or .003" per side.
I have machined a lot of parts on a mandrel 5/8" in diameter using a plunge infeed form toolbit 5/8" wide as shown in the photo.
These were idler pulleys I machined in large quantities, never had any slippage problems, a coolant was used.
The parts were pressed onto the mandrel after boring and reaming to .625" dia, then using an arbor press & a heavy lubricant of white lead & oil.
I still use the white lead & oil (although its taboo today) for lathe centres, works well, but dont get it near the body or mouth (obvious).
Yes, Mandrels are a convenient method of holding work for second operations, & to ensure concentricity, & repeatability, by holding between centres.

Great idea Bruce,
How did you go about lining the boring head up so it would be parallel with the lathe bed.?

Phil

Originally Posted by Steamwhisperer

Great idea Bruce,
How did you go about lining the boring head up so it would be parallel with the lathe bed.?

Phil

Phil thanks for your interest & reply.
I set the boring head up in the headstock spindle. The boring head has a 2MT mount, so I sleeved it up to 4MT to fit into the spindle of the Hercus 260 lathe.
Then revolved it & used a dial indicator to get it running true & on the same axis as the lathe.
Then removed it & mounted the 2MT in the tailstock, adjusted it a few thou towards the operator (me) & took a trial cut. It was right on, first go, too easy !!!!!
regards
Bruce

I really have to learn how to think laterally Bruce.
That was brilliantly simple.
Many thanks.

Phil

Nice and easy Bruce I like it will have a go making a few. Did you make them out special steel ?

I remember using a mandrel like these in a centre grinder back ohh, 35years ago. The mandrel was held in a chuck and was ground to a taper to suit then used to hold gears from the Early Holden Red Motor Oil Pumps. These were for souped up pumps. About 0.250" deeper chamber and gears. The gears were pressed on to the mandrel by hand with the chuck/mandrel and grinding wheel going and then were ground on the external diam or the tips of the teeth. You had to be careful not to hit the grinding wheel with the back of your hand. They were only pressed on lightly as if they were too tight that was when there was a greater risk of hitting the grinding wheel as you removed the finished gear, pulling towards the wheel with minimal clearance to reduce the time to do each part. I did not hit my hand.

I will have to remember this idea as it will have its uses.

Dean

Does anyone think these would be of use to replace a mandrel say for cutting gears on etc? I only ask as i made a mandrel the other day for the 2 gears i had to make for the Antrac lathe. Would these work for heavy cutting and indexing etc?

Cheers,
Ew

Not sure. I suspect that the cutting action and direction of feed could loosen a gear blank if you were not careful. Personally I'd be sticking to a threaded mandrel just to be sure.

Michael

Originally Posted by Ueee

Does anyone think these would be of use to replace a mandrel say for cutting gears on etc? I only ask as i made a mandrel the other day for the 2 gears i had to make for the Antrac lathe. Would these work for heavy cutting and indexing etc?

Cheers,
Ew

Ewan
I can answer from my experience, & the answer is yes, this method of holding gears etc on mills for gear cutting has been used for a long time.
Part of the reason I machined these up, was not only for lathe use in holding parts but also for use in a dividing head between centres on a mill.
When milling, the mandrel can be mounted with the say gear blank pressed on, & then mounted in the mill with the larger dia of the mandrel holding the blank, taking the thrust of the cutter.
A solid & time proven method.
regards
Bruce

Thanks Bruce, they have deferentially move up my rountoit list!

Ew

Your enthusiasm for this hobby is inspiring Bruce.

BT

nice work. and a great thread.
years ago i used tappered mandrels
to hold work on a cylindrical grinder.
IT was a convenient simple way to mount
the job.

Apart from the method that Bruce used to turn the tapers,you do realize that this system of arbors has been in use for over 100 yrs.