Myford thread dial bolt size

Hi Allan,

The thread is 1/4" BSF but mine is a stud and nut.

HTH

Jon

So is mine

Roy

Allan - it doesn't just bolt straight on to the apron; Myford provide a couple of red fibre washers to space the unit off the apron in order to get the graduations to line up properly with the fiducial mark when the half-nuts are engaged. You need to fiddle about and choose the correct thickness combination of washers to do that.

As Roy & Jon have said, it's 1/4"BSF.

....Ahhh, that would explain why mine doesn't line up exactly when engaged then - I have no fibre washers on mine.

Thanks Nigel.

Jon

Go on, you know you want to do it properly. http://www.ebay.co.uk/itm/261467361177?_trksid=p2057872.m2749.l2649&var=560347081093&ssPageName=STRK%3AMEBIDX%3AIT

Allan,

Well if you're wanting to get into threading (otherwise why else would you want the threading dial on?) then why not turn a bit of the lathe?

The stud is plane 1/4" under the dial body rather than threaded - less wear over time although most of the time it'll stay put I know.

1/4" BSF is 26 TPI and you can leave the half-nuts engaged and reverse the tool out as you'd have to do for metric threads to avoid the threading dial issue.

If you need a 1/4 BSF nut to test fit then borrow one from elsewhere on the lathe. The banjo uses two of them and you could manage without one for a moment or two.

HTH

Jon

Edited By Jon Gibbs on 16/03/2017 09:38:48

You could always buy a die **LINK** or **LINK**

The Chronos price is delivered.

Jon

There are so many options - as long as the thread into the casting fits. Threaded rod, bolt (not favourite), a stud with any thread you choose on the other end, metric, imperial, cycle? Nut, thumbwheel, wing nut. Any combination with the other end 1/4 BSF!

The usual reasoning with studs into cast is coarse in the cast end and (possibly) a finer thread for the nut. With a finer thread the nut gets undone and not the stud and is better for high clamping force applications. This is not a high clamping force application, of course. Think cylinder heads for high clamping force requirement.

Threads wear over time with continued use. The stud is easier to replace than the threads in the casting. Remember also that the thread dial has a clearance hole (for the relevant sized stud). Fitting a smaller stud should not be contemplated, even though you 'might get away with it'.

Here's my stud in situ. The stud is exactly 0.250" in diameter (calipers below). You should be able to tell how deep the threaded hole is on your apron perhaps.

Jon

Happy turning!

Edit: When I think about it, it'd be really strange if the stud wasn't symmetrical end-for-end so that ought to give you everything you need.

Jon

Edited By Jon Gibbs on 16/03/2017 11:20:01

H

I always thought that the fibre washers were so that it could be engaged and disengaged without using a spanner

Roy

I think Roy is more likely to be right than Nigel, now that I've examined my threading dial in more detail.

The pinion is free to rotate and is held simply with a cap-screw and washer onto the bottom of the indicator shaft. So, it can be positioned anywhere to adjust its position, irrespecitive of any fibre washers.

I think you just need to engage the half-nuts, mesh the pinion, align the indicator with the witness mark and snug up the cap-screw from below?

Jon