Myford Mystro Lathe spindle thread problem

[chowie]

Hi all,
I'm in somewhat of a quandary, I have recently bought a Myford Mystro Lathe the red 5 speed pulley job with a Mitsubishi electronic variable control.
It has a 1 1/8 x 12 spindle thread, my other lathe is an Axminster having a 1 x 8 TPI thread, I have had an adapter made by a local engineering company but will not run true, but as I have numerous chucks with 1 x 8 thread I would like modify the Mystro's spindle shaft if it is considered possible, or do I just sell the Mystro on.
Any suggestions welcome.
Chowie

 

[Paul Hannaby]

Try a different engineering company? Or buy a chuck just for the myford?

 

[gazza_0208]

Your only real solution is to actually give the complete item to the Engineering Company, I say so as I have done it myself, two local guys I use many hundreds of Engineering Jobs will not even tackle things like this unless they see and have the item, then they can establish the problem, and get a correct solution, "not running true" is pretty basic, obviously not to blame the company that did it, but if they had it to fit they would then have had to correct it. I bet it wasn't balanced after manufacture. I have had many parts made for my Old coronet and they are all spot on, but as I say I have to take it all in when its being finished. I gotta say these guys are boringly precise. Does it run true with nothing attached? :roll:

 

[CHJ]

As gazza_0208 says it's very unlikely that a company will make a really accurate adaptor without having the spindle to work with.

To ensure a really true running part with male and female threads without the spindle means the company would first have to start by:-
Machining the female portion in a blank.
Manufacture a dummy version of your spindle nose on the lathe.
Mount the part machined blank on that dummy spindle nose and complete the turning of the male thread and shoulders.

In effect doubling or trebling the work one might think involved to make an accurate adaptor.

Rather than spending more money on adaptors which are a mechanical compromise anyway I think a chuck designed to fit the Mystro would be the best bet.

 

[chipmunk]

The Toolpost will do a Versachuck to fit your Mystro...

http://www.toolpost.co.uk/pages/Chucks___Accessories/VersaChuck/versachuck.html

And the Sorby Patriot also supports that threadsize.

http://www.robert-sorby.co.uk/patriotchuck.htm

HTH
Jon

 

[CHJ]

The Versa Chuck option has the advantage that at a later date the backplate can be changed to match any replacement lathe.

 

[dickm]

Can certainly confirm that making an adaptor is not a five minute job. If you are making adaptors to fit on the Mystro, it's a lot easier if you just happen to have a Super 7 or an ML7, which have the same nose (my main reason for going down the Mystro route!) Otherwise, it's a matter of making a dummy spindle as CHJ suggests, which is again not a trivial task and certainly not something for a one-off.
Adapting down from Myford to 1" by 8tpi would also be particularly tricky, because there's not much difference between the two to accommodate the threads.
Up here, it would be relatively easy to get a complete new spindle machined up, as there are lots of flourishing small engineering shops serving the oil industry, but elsewhere (and especially in financial services-focused Englandshire) it's probably not so easy.

 

[chowie]

Hi All, I'm just hoping that someone might have a Mystro Chuck 1.1/8 x 12 TPI surplus to their requirements and are willing to sell at a reasonable price, will collect or pay carriage whichever the most practicable.
Can I also at this time promote "Men in Sheds" a AgeUK project aimed at retired men with time on their hands, there are centres all over the UK.
Regards, Chowie

 

[Wildman]

why not fit a backplate to the adapter and true that up on said lathe before fitting the chuck

 

[Myfordman]

I expect after 9 years the op has either got it sorted or given up woodwork!