Boring pulley wheel

What way do people mount a 6 inch pulley wheel for boring on a lathe?Just mount in a four jaw chuck.Turn a shaft to fit the spindle,glue it in place and hold shaft in three jaw chuck and turn the stub end parallel,remove shaft, and hold the stub end in three jaw and bore?

I would clock up the existing bore in the 4 jaw or mount it on a surface plate and do the same thing. Finger type dti's are usually the best option for bores.

I'd also have a piece of material with the same od as the spindle it's going on with say the first 1/4" a couple of thou under so that I could creep up to the correct size.

John

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When machining a pulley or fly wheel sometimes it's possible to get a grip on the spokes of the casting, other times you're probably better off centering the work piece yourself in a four jaw or on a face plate, if it's that big, so long as every diameter is concentric to the next, it doesnt matter if it's not dead on center of the lathe. One quick way to get within 0.2mm is to hold a fine needle point in the tailstock chuck and scribe a cross on the work.

Use it as a guide, until you can't see it deviate in either axis anymore.

Michael W

Edited By Michael Walters on 15/08/2016 21:36:56

I would be more thoughtful re the periphery runout than the spindle hole. Dti'd for true running in both axial and radial direcections, the boring will achieve the target of true running. Setting up on the bore or hub will introduce the opportunity of more error, at the outer circumference, for the same tolerance of the setting procedure.

Please forgive the total ignorance of a beginner but i have absolutely no idea what you are talking about here ( sorry) & it has me interested because the pulley has gone on my pillar drill & i have a blank to be bored & fitted

I got the mount the pulley in a 4 jaw bit ok & was going to do that but

if only i could get past " turn a shaft to fit the spindle" !!!!!! I would really appreciate if someone could elucidate please

Turn a shaft that fits snugly in hole in pulley wheel and superglue in place.Hold shaft in three jaw chuck so that the stub on the pulley wheel can be turned parallel.Remove shaft and pulley from lathe and heat pulley with torch so glue looses it grip and slide shaft out.Mount parallel stub in three jaw and bore

Hang on, you have not bored the hole in the pulley wheel that is in the 4 jaw chuck yet & if it already had a hole in it why not just align the outside of the pulley to run true & bore the hole true & also ( if you need to) tidy up the stub then. Why are you mounting the pulley on a hole that may be out of true & what was the reason for putting it in a 4 jaw chuck in the first place. & why run off a turned up stub when ( surely) the parts that matter are the outside edge for the belt & the centre hole for the spindle

Am i just being totally !!!!

Andy are you enlarging an existing hole in a pully wheel?

If so I would do the same as Not done it yet and hold in 4-jaw, clock the outside true in both planes and then bor eout the hole.

Jason could you clarify that for me please are you talking about holding the stub in the four jaw.

Sam if not four jaw are you saying hold the stub in a three jaw.

I'm not saying anything. I just do not have a clue why we have a pulley in a 4 jaw & something else in a 3 jaw & what it is meant to do !!!!!

Andy, I think we need some Clarification from you.

Is this a raw casting, is this an existing pully wheel you want to bore out. what sort of pully wheel is it. Maybe a photo of teh part you are wanting to work on would clear things up for all of us.

If its a pully being bored out then I was suggesting holding the pully in the 4-jaw, clocking it true and then boringb out. No need to mount on a stub and then turn something to hold.

Edited By JasonB on 16/08/2016 16:08:45

Its an existing pulley that I want to bore larger.

OK in that case as I said provided you can get it into the 4-jaw with its jaws reversed then use that to hold it. Get it running true in two planes and then bore out the hole.

This is the sort of setup to use the DTIs, you will have to watch the chuck jaws don't get in teh way too much, set one dti in the bottom of the existing groove then either use a second or move the first to mesure the side of the groove.

Edited By JasonB on 16/08/2016 17:04:02

If you can't get it into the 4 jaw then hold a stub of bar in the 3-jaw and turn to a good fit in the existing bore, don't remove it from the chuck. Use a small dab of loctite or superglue to retain the pully on teh stub of steel with that boss facing outwards. When the loctite has dried turn the boss true, remove all from the 3-jaw and gently heat to break the loctites bond.

Now hold by the newly turned boss preferably in the 4-jaw, and clock it true as above and bore it out.

I think he could get confused clocking the V for alignment both ways which is why I would clock the bore but I took clocking for the "wobble" as read and not worth mentioning.

In practice it would be clock bore and clock the v for wobble as they will inter react.

It is usually possible to get a dti to register on a small bore but it's easier with a finger type.

John

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Edited By Ajohnw on 16/08/2016 18:27:15

In theory at least it would be unnecessary to clock the V's, as you would've checked the runout of the O/D before you cut them, provided you could sort that out, you could safely presume that once the vees are cut there wont be any runout.

Michael W

Keep up Michael, its an existing pully with the Vees already cut

It would be easier to make one from scratch really apart from the cost of the aluminium.

John

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It's much the same process really, but:

It feels that this would be so much easier to do with a Boring Head in the vertical mill.

... Nice horizontal table to set it up on

MichaelG.

Surely it's as a simple as holding the boss in a 4-jaw and clocking the rim or am I being dense?

Neil