Pulled the Trigger == Lathe coming

[wefalck]

Well, it's difficult to give here a crash-course in turning ... most of the time one would cut towards the chuck, as the main spindle-bearing is designed to take up the cutting forces. However, there are many situations, when one needs to cut away from the chuck, but one would do this for as little material as possible.

 

For the smal pieces in modelling and working with easily turned materials, such as brass or aluminium, a life centre is not really needed, a hard fixed centre is the more precise option. Always lubricate well.

 

When turning wood, the situation is different, as one cannot lubricate and the friction between wood and steel is considerable. So a life centre is needed for longer parts. You probably will find an aftermarket life centre with an arbor of the same diametre as you already have.

 

To my knowledge, the Taig lathe is not bored for any Morse-taper tooling, neither in the spindle nor the tail-stock. Except for MT0 all the MTs would be too large for this small lathe.

 

There are various degrees of freedom, when aligning a lathe: the height and angle (vertical and horizontal) of the spindle relative to the bed ways, the height and angle (vertical and horizontal) of the tailstock axis, the straightness of the bed etc. Most of them are set by the manufacturing tolerances of the lathe and it is not so easy to correct these. So having a test-bar may not be terribly useful, as any corrections (if needed at all) would involve an extensive scraping or shimming action.

 

However, the Taig tailstocks can be 'set-over' for taper-turning, i.e. moved perpendicular to the axis of the lathe. This means that every time you have loosened the locking screw, you would need to re-align the tailstock. An old-time machinists' approach is to use two fixed centres, in the spindle and in the tailstock, and hold a razor-blade between them. If the centres are aligned correctly, the blade should be perfectly vertical and at 90° to the bed.

 

Otherwise, I would not get worked up too much about such alignment issues, as they are likely to be well within the tolerances we are working in. On my watchmaker-lathes I can easily work to within a 1/20 or even 1/50 of a millimetre. That should be more than good enough for shipmodelling purposes, unless perhaps you are building a steam-engine. I would guess, that on the Taig you can also work to 1/20 of a millimetre (assuming that the handwheels are graduated at 1/10 or even 1/20. 

 

 

[Toolmaker]

22 hours ago, wefalck said:

An old-time machinists' approach is to use two fixed centres, in the spindle and in the tailstock, and hold a razor-blade between them. If the centres are aligned correctly, the blade should be perfectly vertical and at 90° to the bed.

Brilliant!

I’ve spent 40 plus years hanging out around machine tools and I had never seen, heard or considered that. I can clearly see it in my head though. It’s the sort of initial alignment check you could do during a rebuild. 

 

One approach to working more accurately than the handwheel graduations is to put a dial test indicator (dti) against the slide and take your movement from those. This method is more easily done on larger machines with metal bedways and less size constraints. The dti is usuall on a magnetic block.

A good digital readout is even better, thus removing the pesky backlash error.
Oh the wish list is endless.

 

[kgstakes]

I have a question on my taig lathe it comes with these rather large jaws on the 3 jaw chuck.

 

 Question,  has anyone taken those jaws and milled or turned them down so you have step jaws?  Hope I’m explaining these correct.

 

Or would it be better to buy a step 3 jaw chuck?

 

 If turning them down to make a step jaws would it be easy enough to do for basically a beginner turner.

Edited February 10 by kgstakes

[wefalck]

Well, I would rather first get a bit of experience in turning, as the quality of all your parts depends rather on the precision with which you have turned down the jaws.

 

You would need a round piece of very good quality, such a ground piece of tool-steel. Onto this you tighten the jaws and then you can turn the outside of the jaws.

 

However, you just end up with a set of stepped soft jaws. If it was me, I would get myself one of those self-centring chucks from Sherline - I think they do them with the right thread for the Taig, but I am not sure. I have several of those Sherline chucks and they are perfectly adequate for our kind of work.

 

Having said that, I find that I rarely use the 3-jaw-chucks for modelling work, they are mainly used for tool-making. Whenever possible, I use collets. much safer to work with.

[kgstakes]

That’s what I was thinking just buy another one.  I seen people turn them down to different jaws but me too I bought the collets and I’ll probably use them most of the time even if I turn a part for a piece for a miniature furniture project.  My set goes up to 1/4 or a little more but not 3/8 diameter.  
 

just wondered if it was possible.  I like the sherline 3 and 4 jaw (I think they make a 4 jaw) better than the taig chuck.

 

i do like that you move the carriage right at the carriage instead of at the end of the lathe.  I guess you get use to it but that was one of the reasons I went with taig.

 

 Happy with it so far,  turned a few things (messing with it) but since I’m still down to only one hand still I’m not getting too serious about it yet.  With finger tips crushed it’s hard to do anything let alone go to work.  When you need both hands to do your job it’s a bitch if you can’t use one.  Just take time to heal,  but I got models to build😡🤪😀

[kgstakes]

I can see a dail indicator in the future for my lathe if for nothing else just because you can see what you’re doing.  Digital would be better. We’ll see what the future brings.  All kinds of options you can think of and see if they work.

 

 It’ll be fun working with my little lathe and see what I can do with it and I know in time just like anything else you’ll get better the more you use it.

 

 Thank you everyone again you’re all the greatest in my mind and I know if I need to find something out or have someone teach me singing new,  jets the place to ask.

 

 Thanks appreciated 

[Toolmaker]

I can only offer advice based on industry standard machines. Although I use a miniature Sherline milling machine I do not currently own a model makers lathe.

That said, in the past, at the spindle end I have used 2 jaw, 3 jaw, 4 jaw and collet chucks. Most of the 4 jaw chucks have had independent jaws but self cantering 4 jaw chucks are also common. I have worked with a 4 jaw chuck in a 3 jaw chuck and with a 3 jaw in a 4 jaw.

 

Regarding soft jaws and their use.

 

Soft jaws are available for many 3 jaw chucks and certain collets systems have soft collets available. Soft jaws/collets are predominantly used for second operation work. That’s when you have worked on one side of a part but still have work to do on the other side and want to hold it in an accurate manner. Most 1st op work would be done in hard jaws.

 

So most soft jaws become stepped. You can step the inside of the jaws or the outside. The jaws have to be locked firm when you machine them. For utmost accuracy If you are stepping the inside of the jaws (to hold on the outside of your part) then you should clamp a piece of round bar in the chuck and bore the jaws to the same diameter you want to hold your part or very slightly larger. Conversely if you want to hold on the outside of the soft jaws you should hold a ring on the outside of the soft jaws. This method is to give better likely concentricity accuracy but in practice hobby machinists will likely clamp the jaws the same way as before, on a piece of round bar.

 

Full soft jaws, sometimes called pie jaws, are useful when holding thin walled parts. These parts might likely distort if you held them in traditional 3 jaws, soft or otherwise.

 

One instance when you might wish to bore soft jaws through is when you want to avoid damage from hard jaws, whilst wanting good concentricity from one end to the other of a shaft.

 

You can also have soft jaws for your milling vice allowing you to hold specific shapes and without needing parallels.

 

To be honest, most of this is referencing model engineering rather than wooden ship building but take it as a snapshot of soft jaw usage. I’m sure lots of usage videos are available on the internet.

 

Most important message is work safely. 50 years ago I was told by a foreman “you can walk on a wooden leg, but you will never see out of a glass eye”.