Myford ML7 Resurrection - A New Summer Project

[redgrouse]

This manual may be useful

 

[SightlessSeer]

Congratulation's on your "find" it will make a useful machine with some TLC

The reason your gib screws are tight in the actual machine is you are making 3/16" BSF -- 0.1875" dia 32tpi 55deg and the one factory fitted are 2BA --- 0.185" Dia 31.5tpi 47.5deg They often do fit but never properly and are not really interchangeable.
Useful thread chart here but there are lots around of course plus the Zues book !

Thread Chart - motalia.co.uk

Description

www.motalia.co.uk

John

That would explain some things... I did use a thread pitch gauge when trying to figure out what thread it was and 32 TPI didn't quite fit, but was super close. I assumed that it was because it was 55° thread profile, but if 2BA is 31.4 TPI that would explain it. Sadly my Atlas won't cut 31.4 TPI, so for now I'll stick with the ones I made, but if I have to do an order from Myford (or somewhere else that sells 2BA) I'll definitely pick up a handful of replacements.

This manual may be useful

Thank you for this! I'm sure it will come in handy.

 

[SightlessSeer]

I don't have any pictures to share at the moment, but I have largely finished the new cross slide gib. I still need to mill the dimples for the gib screws to register into and mill the 60° relief into the long edge of the gib. I also picked up some 2BA screws which I proceeded to modify into proper gib screws instead of my jerry rigged gib screws (did it matter? No. Am I happier now that it's right? Yes).

After some further investigation, I found that my head stock casting is different from the one that Wolfgang from this thread used. The distance between the bearing cap bolts is narrower than the casting that he had. As such, if I'm going to convert to roller bearings for the spindle I'm going to have to come up with my own modification instead of blindly following his. Too bad.

I'll make a bigger post when I have more progress to report, but at the moment I'm trying to figure out how I'm going to fixture the gib to cut the relief angles into it. The easiest approach is probably some sacrificial bolts and round stock to push it into the dovetail of the cross slide, but we'll see what I come up with.

 

[WobblyHand]

Looks like you got the 2BA screws. If you need some made, let me know. I have an electronic lead screw on my lathe and could program it to 31.4 TPI if needed. Is that meant to be 10*pi? Is that a 55 degree screw? Anyways, if you need something like that, let me know.

Looks like a fun project. And you got a steal on it!

 

[SightlessSeer]

Looks like you got the 2BA screws. If you need some made, let me know. I have an electronic lead screw on my lathe and could program it to 31.4 TPI if needed. Is that meant to be 10*pi? Is that a 55 degree screw? Anyways, if you need something like that, let me know.

Looks like a fun project. And you got a steal on it!

That would be awesome! For the time being I should be alright, but if I need any more I'll definitely send you a message.

My understanding is that 2BA comes from a swiss watch/clockmaker's standard that the British adopted as their own. The pitch is defined as 0.81 mm and the thread form is 47ish° if I recall correctly. It's a bit goofy.

 

[WobblyHand]

That would be awesome! For the time being I should be alright, but if I need any more I'll definitely send you a message.

My understanding is that 2BA comes from a swiss watch/clockmaker's standard that the British adopted as their own. The pitch is defined as 0.81 mm and the thread form is 47ish° if I recall correctly. It's a bit goofy.

Don't know that this is definitive, but here's an entry on Wikipedia: https://en.wikipedia.org/wiki/British_Association_screw_threads
0.81mm pitch for 2BA with a 47.5 degree thread form.

If it comes to it, I'd need a 2BA (or whatever) nut, as I can't properly measure pitch diameter with my thread micrometer, since I have 60 degree forms. I can grind a thread form to close to the correct angle. I think, maybe one could calculate out pitch diameter with thread wires, the math would be different though. Found some 2BA nuts at https://britishfasteners.com/2ba-standard-nut-7066.html

Anyways, let me know. It would be an interesting challenge... No, I don't have the thread preprogrammed, I'd have to figure it out, but that's part of the fun.

 

[SightlessSeer]

Don't know that this is definitive, but here's an entry on Wikipedia: https://en.wikipedia.org/wiki/British_Association_screw_threads
0.81mm pitch for 2BA with a 47.5 degree thread form.

If it comes to it, I'd need a 2BA (or whatever) nut, as I can't properly measure pitch diameter with my thread micrometer, since I have 60 degree forms. I can grind a thread form to close to the correct angle. I think, maybe one could calculate out pitch diameter with thread wires, the math would be different though. Found some 2BA nuts at https://britishfasteners.com/2ba-standard-nut-7066.html

Anyways, let me know. It would be an interesting challenge... No, I don't have the thread preprogrammed, I'd have to figure it out, but that's part of the fun.

I have about 8 2" long fillister 2BA screws left, so hopefully that will be enough for this project. I'm hoping that I don't have to get anything shipped across the ocean for this thing. If it comes to that I'll probably pick up a couple of 2BA taps and dies to help make it worth it.

 

[redgrouse]

That would be awesome! For the time being I should be alright, but if I need any more I'll definitely send you a message.

My understanding is that 2BA comes from a swiss watch/clockmaker's standard that the British adopted as their own. The pitch is defined as 0.81 mm and the thread form is 47ish° if I recall correctly. It's a bit goofy.

Hi, glad you seem to be sorted with the BA screws but incase you need it look hear at this UK supplier

Ba Steel Threaded Bar, Threaded Bar,Ba Studding, BA Steel Studs, 2BA,3BA,4BA,6BA,5ba,7BA threaded bar,ba Bolts,

If you needed to purchase some more items - its, bolts, threaded rod, Taps & Dies let me know if I can help -- happy to purchase and post to you as a gift which for small value items saves a heap of paperwork. Message me direct if you need to.

BA was instituted by the British Science Association who "looked after" the scientific community of the era [1800's] and for some reason used a mathematical progression for the sizes. BA was indeed used by clockmakers and many other manufactures of scientific instruments, gauges, gunmakers etc indeed almost all small mechanical mechanisms used BA threads. As a side note Whitworth threads were also used down to 1/16" and I have come across 3/64" on an old Hardy fishing reel !

 

[WobblyHand]

I have about 8 2" long fillister 2BA screws left, so hopefully that will be enough for this project. I'm hoping that I don't have to get anything shipped across the ocean for this thing. If it comes to that I'll probably pick up a couple of 2BA taps and dies to help make it worth it.

FYI, British fasteners is based in the US. Don't know if that makes it easier or harder for you to use, rather than sourcing from the UK.

 

[SightlessSeer]

FYI, British fasteners is based in the US. Don't know if that makes it easier or harder for you to use, rather than sourcing from the UK.

Oh that's awesome. US is much easier. I'm not too far from the US boarder so worst case scenario I can ship it to the UPS store there then pick it up. Thanks for the tip! That is actually a great option knowing that. I still want to get some 2BA nuts, but I only need 2 of them (lock nuts for the gib for the carriage half nut). If I can put together an order worth bothering with I'll probably use them.

Hi, glad you seem to be sorted with the BA screws but incase you need it look hear at this UK supplier

Ba Steel Threaded Bar, Threaded Bar,Ba Studding, BA Steel Studs, 2BA,3BA,4BA,6BA,5ba,7BA threaded bar,ba Bolts,

If you needed to purchase some more items - its, bolts, threaded rod, Taps & Dies let me know if I can help -- happy to purchase and post to you as a gift which for small value items saves a heap of paperwork. Message me direct if you need to.

BA was instituted by the British Science Association who "looked after" the scientific community of the era [1800's] and for some reason used a mathematical progression for the sizes. BA was indeed used by clockmakers and many other manufactures of scientific instruments, gauges, gunmakers etc indeed almost all small mechanical mechanisms used BA threads. As a side note Whitworth threads were also used down to 1/16" and I have come across 3/64" on an old Hardy fishing reel !

Thank you for the info, and especially thank you for the offer. I'm still holding onto a faint glimmer of a hope, but I will absolutely take you up on that offer if it comes down to an over-seas order.