Tailstock in the way...

[dcmguy]

I think I know the answer to this but my experience is that just because I think I knw something that doesnt make me right!

I'm trying to specify a larger lathe for myself, primarily to take the Volmer Oval Device for oval turning. I expect though that I'll also want to use it for regular turning for pieces that dont fit my current lathe (which is effectively max 10" diam over banjo).

I've been consideting the larger lathes by Vicmarc, Robust, Wivamac and Steinert having finally decided to reject the Wadkin, Fell etc older gap bed machines.

The issue I've not got my brain round is the tailstock :

- When oval turning you really dont want a tailstock on the bed as it's directly in the way.

- In simple terms it seems to me that sometimes it would help when hollowing bowls if they could be approached from the end of the bed or the other side of the bed.

- I'm certainly not paying for a big 'lathe for life' where I have to lift a heavy tailstock off and on... time will stop me being able to do so!

- Ideally I'd like to be able to turn and sand a whole (larger) bowl or hollow form without messing about with taking the piece off the lathe (ie turn underside from headstock end, inside from tailstock end)

- I also suspect that a rotating headstock reduces rigidity and is a bit of a pain to re-align mid project and doesnt help with the oval turning issue.

So, the Steinert and Wivamac lathes have rotating headstocks and both the Robust and Vicmarc tailstock swing-aways seem to put the tailstock exactly where I'd want to be standing to start cuts on the inside of a bowl.

Has anyone thought this through or have a helpful opinion please ?

 

[graduate_owner]

A friend of mine has made up a winch system that he bolts to the bed of his ( metalworking) lathe so he can lift chucks to change from 3 to 4 jaw. These chucks are about 10 - 12" and probably weigh at least a hundredweight. The actual winch is a cheap affair but capable of pulling half a ton, so lifting the chucks is well within safe limts ( although some winches are specified for pulling, not lifting).

Could this be a solution for you?

K

 

[Mark Hancock]

I've only ever had swivel headstock lathes over the last 28 years and have never had an issue with rigidity. They allow you to do everything you've mentioned in your post (ie turn underside from headstock end, inside from tailstock end) and with better access especially when hollowing out - you don't have to stretch over the bed and can use your body to support the tool (a much better way of turning IMHO) provided you go for a well designed one. By that I mean it has a big enough banjo so that you don't need a free standing tool rest or bowl turning attachment/arm when you swivel the headstock.

As for re- aligning my Titan 315G has a pin that simply slides into the turret under the headstock and aligns perfectly; couldn't be simpler Have a look at the Titan range ( 3 models 315, 400 & 315G)
https://www.classichandtools.com/acatalog/The-Magma-Black-Line-TITAN-Lathes.html
I'll have my 315G at the European Show http://www.europeanwoodworkingshow.eu/ if you want to see one in action. I'll even let you have a go if you ask nicely

Mark

 

[dcmguy]

Thanks both. I hadnt thought of a winch or considered Magma ...so those are both helpful ideas.

I'm happy to accept that a rotating headstock isnt a bad thing... I've not got the experience to know either way.

Tailstock in place is an issue for oval turning so it needs to be shifted off lathe bed.

My first solution is simply to have a small extension bed to push the tailstock onto and move it (the extension bed plus tailstock) away. But this would mean 4 legs on the extension bed (ie pair at each end) and wheels on at least one end. No-one does that (yet) that I can find and getting someone local to weld on legs with wheels (& get the height spot on) seems a bit of an ask.

My second solution is to dedicate a big lathe to oval turning and junk the tailstock. If I then want to turn stuff over 10" I can replace my ' 10" over the banjo' lathe with a bigger one.

I just hoped it would be easier & cheaper to buy one lathe rather than two!

 

[Inspector]

I noticed you don't have the Oneway lathe on your list. :shock: If you look at their wares you will see they make a good outboard attachment. Assuming the oval chuck can be had in a left hand thread you could do all your oval work from the outboard end of the headstock while still keeping the tailstock on the inboard side. I suppose the Robust would have a similar option if you don't like white lathes from the great white north. :deer The earlier suggested lathe lift is a good one or you could get an electric winch with a track that bolts to the ceiling. It would also be useful for lifting big blanks on to the lathe.

Pete
https://oneway.ca/products-category/lat ... ight-Extra)

 

[graduate_owner]

Your idea of making an extension to the bed sounds interesting. Could you do this yourself? Since the bed only need support the weight of the tailstock, as opposed to being sturdy enough to actually hold work rigidity between centres, it won't need to be a massive construction. I'm thinking perhaps angle iron, possibly Dexion type steel, making up splayed legs for stability, with diagonal bracing. Four inch castors will allow easy positioning. If you had someone to just weld a steel plate at the base of each Dexion leg, say 1/4" thick, and then weld a length of threaded rod ( say 3" of 12 mm rod) onto the castor, ( might need a sleeve over the rod and the castor mounting thread) then you could drill the steel plate and tap a 12 mm thread which will give you 3" of height adjustment by just screwing the 12mm rod in or out. Then use 12mm nuts on either side of the steel to lock in position.

So you would have the base, height adjustable and mobile - then you would need a platform or whatever to actually support the tailstock. I don't know what would work there because I don't know the bed arrangement, but possibly something as basic as a flat 3/4" ply platform with a slot cut out to accommodate the tailstock locating bolt. Would this work for you? I suppose it would be sensible to rig up some way of securely fixing the stand to the lathe because Sod's Law will ensure the platform moves when you try to slide the tailstock on to it. Anyway is it worth considering? If it works it would be immensely cheaper than having to buy a second lathe. Two lathes means extra space taken up, and extra cost of chucks etc unless the spindle threads are the same. Also if you can see this working then you might be able to consider one of the lathes that you have previously discounted as being unsuitable.

Or get a winch? As has been suggested this would be useful for more than just the tailstock.

K

 

[dcmguy]

Thanks both again!

Inspector : I'm def not biased against Canada ... in fact during my long since finished career the only boss who didnt muck me about was a Canadian. I've had a good look a Oneway and in fact Peter Mortimer is still, I think, looking to shift his 2436. My rationale for excluding them, of course, may be wrong. The oval chuck is 35kg ish, and while Oneway do have 4 bearings (unlike all others, as I understand it), the strength is on the bed-side. Ignoring second hand (which also may not be rational) I'm not convinced they're better than a Robust AB, yet the price point is above Wivamac and Vicmarc. I'm certainly prepared & willing to be educated though. Sliding headstock, plenty of turning capacity, stainless steel bedways, shortbed with bed extension (for depositing the tailstock), plenty of power etc..these arent to be ignored!

Graduate Owner : I'm not into welding, metal fabrication etc so would just have to pay for someone to do all that. Your suggestions though did help me think abit more. I can just buy a short bed extension and a hydraulic scissor table (<£200).. slap the extension bed on the table.. pump it to the right height to attach, slide tailstock on then wheel it away ! cheers!

 

[LaymarCrafts]

I have a Wivamac 6000 chichis short bed lathe and I have a Tailstock Drop Down device supplied by Wivamac.

Ostensibly this is a short section similar to the lathe bed onto which the Tailstock slides and then with a downward push it hinges down out of the way.

A simple solution that works perfectly.

Richard

 

[BertD]

I have a Vicmarc 300 with a tailstock swing away, it moves the tail stock out of the way perfectly with very little effort. No lifting at all and no interfence with access for large bowl turning and or coring. In addition it has an attachment bolt option, that can be used to lock the swing away extension to the main ways proving additional length for spindle turning, sweet.

 

[dcmguy]

Thanks Richard and Bert. It's good to know that the tailstock kits for the big name lathes work well.
I think the issue I have is that for oval turning you work straight onto the centre line (eg from end of the bed) whereas for spindle/bowl turning its more typically from a side of the bed.
It seems that its only the Robust Liberty (which is too small a lathe for what I want) has the tailstock solution I like.

Maybe though I just need to havesome turning lessons from an oval turner and then I can actually understand (rather than theorise) how much tailstock position would be a problem.

Thanks everyone again for the help.

 

[finneyb]

Have a look at the afternoon session http://www.carolinamountainwoodturners.org/articles/514 he is working with the tailstock in place.
Dale Larson is a past president of AAW and I know does oval turning and teaching if you fancy a trip to Oregon

HTH

Brian

 

[Inspector]

Gasp!!!! And on a Oneway too. :shock:
:wink: Pete

 

[dcmguy]

Thank youBrian. That's remarkably helpful.

Ignoring the fact that he's vastly more competent than me, he's using the same device (the VOD) as I am planning to and is turning it on a longbed ...long enough for the tailstock not to be in the way.
Also, as Pete points out, its a Oneway which means that the second hand 2436 would obviously be ok enough for me.

For some reason I'd assumed that the best approach would be to drag the headstock up to near the end of the bed and stand directly at the end of the bed (hence the Wivamac tailstock drop would then be i the 'wrong' place) or to use a very shortbed like the Vicmarc300. Goes to show there's a big difference between practice and what goes on in my head !!

Not sure the wife would be overenthusiastic about me trotting off to Oregon ...though I quite like the idea!

many thanks

 

[finneyb]

This may be useful http://www.woodworkersemporium.com/oval ... le-larson/ Dale Larson uses a Vicmarc Oval Chuck.
Seem to remember that David Springett made one from wood.

Brian

 

[J-G]

Seem to remember that David Springett made one from wood.

Yes he did but his book on the subject is out of print with little chance of a re-print.

I also made one for my Myford Super 7 but there was little interest when I posted details

Being a pedant, I wish people would not use the description 'Oval' - the correct term is Elliptical - turning an Oval is much more difficult and the commercial chucks which were available up to the 1950s turned Ellipces.

 

[duncanh]

At demos I'm always surprised that none of the turners rotate the headstock and turn with it rotated off the bed even when the lathe has the capability (for demos you could realign the whole lathe to enable the audience to see if you wanted the headstock rotated).
Turning with a rotated headstock means you don't have to lean over the bed and comfortable. I'd never consider a fixed headstock. To realign doesn't take long - the lathe either has a built in system or either align centres by eye or push the headstock back with a centre in the tailstock (which is what I do).

If you really want a fixed headstock either get a lathe with a swing away/drop down bed extension for the tailstock or make your own. My tailstock just sits on the floor on the odd occasion that I don't need it

 

[finneyb]

Seem to remember that David Springett made one from wood.

Yes he did but his book on the subject is out of print with little chance of a re-print.

I also made one for my Myford Super 7 but there was little interest when I posted details

Being a pedant, I wish people would not use the description 'Oval' - the correct term is Elliptical - turning an Oval is much more difficult and the commercial chucks which were available up to the 1950s turned Ellipces.

I see your point an egg is an oval whereas an ellipse is symmetrical because it is moving between two fixed points which is what DS's chuck basically achieves.

There may be more interest now - can you find your thread and post it?

Brian

 

[finneyb]

David Springett did an article in Dec 2015 American Woodturner on his shopmade 'Oval'(sic) chuck . (DS's words not mine !!)
https://vimeo.com/142546805 accompanies the article.

American Woodturner is the AAW magazine - you could join AAW as a digital member, I assume you still can ie you don't get the paper copy of the magazine , but you do have access to their back copies.

Brian

 

[dcmguy]

It's a fun subject for those who are so inclined! (I happen to have a degree in maths so quite enjoy thinking about it).

The Vicmarc 'VOD' (varyingly described as the Volmer Oval Device or Vicmarc Oval Device) was created by Vicmarc in collaboration with Johannes Volmer (now sadly passed away). For fok who are interested this link is a good place to start (English editor being, ofcourse, David Springett)..

http://www.volmer---ovaldrehen.de/englisch.htm

As for semantics between oval and ellipse ... my guess is that folk refer to oval as its a more readily understood concept than 'ellipse' ...the latter being typically defined by a mathematical equation ...and maths often has a habit of making folks fall asleep!



(by way of illustration of irrational ambition .. I have in mind a set of scaled nested oval bowls to try to represent the planetary orbits in our solar system...which..when relfected on... is non-trivial without excessive simplification!... maybe I'll develop the skills and creativity to do this nicely one day!)

 

[J-G]

I see your point an egg is an oval whereas an ellipse is symmetrical because it is moving between two fixed points which is what DS's chuck basically achieves.

Thanks Brian - when I 'go on' about Oval and Elliptical, most people roll their eyes :roll: :roll:

There may be more interest now - can you find your thread and post it?

It never got as far as a 'thread' in its own right - just a few posts within other subjects.

Thanks also for the link to DSs Video which (despite a deal of searching) I hadn't found. Had I done so I might have taken less time to build my chuck which I did from first principles. The big advantage though is that my chuck has variable eccentricity - witness the attached image - which I'm sure the old commercial products also had.