Need chuck thread cutting Wadkin Bursgreen BZL

Yep, got that one on my watch list

Having not done much threading... I have to ask, would it be worth buying tap 1, 2 & 3? Or should I just aim for the final one? In my mind, I am guessing these are deeping cuts as you go down the numbers. 1 being the shallowest, 3 being the deepest. Is it something like that?

Just my view but i would go with a second or taper, as the finishing tap probably wouldn`t initially engage with existing thread immediately and by using the second tap for instance you would have some engagement and more likely to go in straight.

Also you would be cutting slightly less off initially with a taper or second tap until it reached the full threaded area of the tap.

Someone else may have a different view.

Taps are usually taper , second and finishing . with the finishing having the greatest amount of fully developed threads.

Thanks Mark!

My dad ordered a set of 3 taps. So he should be able to start with the taper and work his way through to get a good fit.

Is there any risk of cross cutting the thread here? Or should it slide in to the current thread relatively easy? Debating whether I should drive back to help him out one day...

I suppose at this stage, the only measurement that matters on the spindle OD is the very end bit at the start of the thread. A light filing of the first turn or so of the thread might be all it needs to ease it in.

Not much chance of cross threading an existing 1" BSW thread. The taper or second cut tap should follow the thread in as long has he holds it somewhere near to square to the job.

Edited By Hopper on 03/11/2016 04:06:32

I've arrived very late to this discussion but it looks like there's something very strange going on here. I think it is entirely possible that, at some stage in its lifetime, the spindle has been removed and re-fitted the wrong way round. Compare the fourth picture down on the lathes.co.uk site, following the link provided earlier in the thread. Assuming that the orientation is that the "chuck" end is to the right, it is plainly a right hand thread, as you would expect it to be to prevent the chuck - or more likely for a wood turning lathe, a centre or faceplate - unscrewing during turning procedures. The opposite end has a left hand thread, again as you would expect for bowl-turning, etc. Also, referencing the same picture, what appears to be a removable collar, matches more closely the "register" shown in Richard's close-up of the spindle thread. There is no mention of a taper in the nose of the spindle, nor can one be seen in the photos. I'm not "au fait" with woodworking lathes, so I don't know if its normal to have a taper at both ends or not. Doubtless someone on here will enlighten me.

My final piece of evidence, Watson, is the Warco table, supplied by John Gibbs, which clearly lists the T04M under the right hand thread section.

I suggest that the OP has another look at the lathe to ascertain whether my supposition is anywhere near the truth. It may mean you end up with a chuck with the wrong thread but that could be better than try to field a flying chuck as it unscrews from the spindle and launches itself across the room!

And finally, surely someone on here lives nearer than Richard to his father and could pop in and have a peek after a private exchange of addresses?

John

Thanks Hopper, I'll keep this in mind. I think he'll have the taps by next week so I will try and go over to help if possible...

John there is usually a MT 2 hole in the inboard side ,larger side of the spindle.

It is more usual to have a chuck on the inboard side than the outboard side.

http://www.wadkin.com/uploads/files/Wadkin%20BZL%20Lathe.pdf

Edited By mark smith 20 on 03/11/2016 10:23:38

Parts manual

http://www.advancedmachinery.co.uk/content/document/BZL%206%20MANUAL.pdf

Edited By mark smith 20 on 03/11/2016 10:25:27

Thanks John. I've had a very kind offer and have no issue with traveling, so not to worry. But hopefully we'll be able to get this sorted out without anything more involved

Your observations are half noted throughout. There are anomalies with the spindle which I've been confused with as well. On many photos, they show the larger diameter thread of the spindle (which we assume is 1 x 8 BSW) on the inbound side, including on original documents from Wadkin Bursgreen.

Studying this photo it shows the larger diameter thread, which in this case is on the inbound side pointing towards the tailstock, is a right hand thread, correct? It is perplexing, as on mine and Paul's, the larger (1 x 8 BSW) is definitely Left Hand and on the outbound side.

However, even the original photos from Wadkin show some differences. For example, the larger faceplate being fitted on the outbound side, which on their diagram is the smaller thread. Whereas on ours, the large faceplate matches the largest thread size, which is on the outbound side.

Similarly, Paul (on page 2) notes that he has a BZL himself and that his outbound thread is also 1 x 8 BSW LH.

Perhaps two different people have swapped the spindles over years ago. Would there have been a reason for this?

But the fact that the original larger faceplate fits the outbound side to me seems to suggest Wadkin Bursgreen may have just changed some of the specs over the production run. From the "operating instructions, maintenance and parts list book. Wood turning lathe type 6" BZL" I got from Wadkin Bursgreen, who otherwise don't keep much info on their "antiques", it says:

"The spindle is threaded at both ends to recieve chucks and faceplates. All centres with a No. 2 morse taper shank will fit over the taper bore in the spindle end, which is over the bed. The centre can be ejected from the spindle by means of the knock out rod provided, being placed down the center of the spindle and given a sharp tap"

Neither end has any means of receiving a morse taper on the lathe my dad has. I wonder if Paul's does?

edit: just to mention another difference / variation, ours does not have the removable section over the bed for larger diameter  turning (which could have been useful! but oh well).

As I'd wondered before, perhaps the spindle has been replaced at some point. Or perhaps the production run changed slightly over time. Eitherway, I think we will hopefully be able to get it working soon, once we try re-threading the chuck.

Edited By Richard Harris 5 on 03/11/2016 10:51:26

Mark Smith 20,

Thanks for the heads-up on the tapers. The links will be useful to those who haven't access to those manuals. Unfortunately neither address the issue of the left hand thread on the spindle nose, leading to the possibility ( or probability ) of the faceplate/chuck unscrewing in use.

John

I am not a turner so I am trying to picture this. The LH thread is on the outbound side, which would be turning clockwise as you face it, correct? And the direction of turning the chuck onto the LH thread would be counter clockwise?

So if you want to remove the chuck, you are turning it clockwise to turn off? The same direction as the spindle will be turning?

Does that mean a chuck / faceplate could spin off?

Wouldn't it be the same on the inbound side then as well?

Think of it from the centre of the headstock looking towards each chuck in turn - inboard and outboard.

A RH thread for the inboard side and a LH thread for the outboard side is absolutely correct to tighten the threads when its turning towards the operator.

For woodturners, and I include myself here, turning on the outboard side requires a significant change of action that requires practice - particularly for those who've always turned inboard but it's entirely possible to get the muscle memory.

Jon

Richard,

Does that mean a chuck / faceplate could spin off?

Wouldn't it be the same on the inbound side then as well?

The intention is that whe the spindle is turning in the normal forward direction, the chuck/faceplate is always being "tightened" on its thread when under load. Starting the spindle will always ramp up faster, ie motor switch on, power off and the spindle slows as it looses inertia, and chuck/faceplate does not have a tendency to spin off.

Oh thank you, that is good to know. This is how I hoped it would naturally work - with the direction tightening the faceplate, but that got me worrying it was going the wrong way for a moment

Oh, dear! I'm beginning to wish I hadn't reopened this particular can of worms!

I must confess to being a little confused by the use of the terms "inboard" and "outboard" when referring to the ends of the spindle. I assume this is specific to woodturning and that inboard refers to the end facing the tailstock and outboard is the end hanging out in the fresh air for a faceplate or large bowl turning.

Either way, I'm still convinced that the thread facing the tailstock should be a right hand thread, as I think has been established. So that leaves you with a thread going the "wrong" way on your spindle - or the spindle is installed end for end.

Over to you . . . .

John

My understanding is that the LH thread in question is the bowl turning one 'away from the tailstock'

Neil

Correct. On our machine: LH thread outbound, RH thread inbound.

Are we going to die? :O

Good. Glad we got it sorted . . . . . Or did we?

I'm off for a cuppa; my brain hurts.

John

So the taps arrived with him, set off 3.

I explained how to use his lathe to make alignment easier and start the threading. But then after the weekend he says he felt it was too risky and didn't feel like doing it himself. So he has a friend at work who is very familiar using a engineering lathe to do it.

Their idea is now to buy a 1 x 8 BSW LH die and make an adapter for it.

Can someone else comment? To me, this makes no sense. Both the chuck and the lathe are 1" diameter - a thread adapter will not fit unless:

a) the bore out the chuck (for which, we don't know how much material is actually in there)

b) the take the spindle off and turn it smaller (for which, they'd need a 1 x 8 metric die to fit the current chuck thread).

Am I confused?

Yes. You are confused. There is no such beast as a 1'' x 8tpi metric thread. Until you sort out what threads you are dealing with, you will get nowhere.

First step should be to call Axminster and ask them whether the thread on the chuck you bought is 1" BSW or 1" UNC.

Making an adaptor to fit a 1" x 8tpi LH threaded chuck on to a 1" x 8tpi LH threaded spindle makes no sense at all.

Edited By Hopper on 08/11/2016 11:02:19

RIGHT, I am confused! Thank you Hopper.

So the chuck is definitely at 1" x 8 LH UNC threadform, confirmed by Axminster. Imperial (- sorry).

So the idea of running a tap through the chuck makes sense still? As well as confirming the OD of the spindle thread, and if needing, lightly removing some material.

But they're both still the same OD, 1". How can they be making a thread adapter? Without the aforementioned issues?

Edited By Richard Harris 5 on 08/11/2016 12:00:08