Myford ml7 toolpost bolts

Hi,

does anyone know what size these bolts are.

as you can see I need another 4, hopefully Myford do some spares.

thanks

chris m….

I no longer have a Myford 4-way toolpost, but, as I remember, the screws were 1/4" Whitworth, ( or possibly 5/16" Whit.you need to measure).

In any event, they will be available as standard Whitworth allen screws, I'd look on Ebay.

Edited By Clive Brown 1 on 11/07/2022 16:55:02

Why not measure them so you can source them locally and cheaply?

All it takes is a caliper - which you'll need to use the machine - and a thread gauge.

I would make sure you buy top quality screws, the sockets take a lot of use on a toolpost and some cheap no name screws are not as tough as they should be and the fit of the socket can be less than good.

Mike

They look like 1/4 BSW., and I no longrer have a ML7 to check, just your picture showing a coarse thread.

If you start collecting capscrews of various sizes and threads, You will soon be able to find out such things in a matter of minutes, AND they will useful for tasks such as this, so that you can find a solution yourself...

Expect to find threads on a ML7 to be BSW, BSF or possibly BA for gib strips.

A machine of that age (Launched in 18947, so designed before then ) so will be Imperial sizing, unless it is a machine manufactured on the Continent.

Howard

Yes they are 1/4BSW - GWR Fasteners do 'em.

Howard, do you know if the originals had dog-points?

Would expect the originals to be flat ended to minimise digging into the tools.

In use, they probably mushroom, so might be worth turning away the first couple of threads, to core diameter, since they will be in fresh air, and doing nothing anyway. That should make them easier to remove when they do mushroom and need fettling.

For Chris's benefit, just go to your local hardware stockist (Here in Peterborough its Sterling Nut and Bolt ) and buy some.

If they have a minimum order policy, buy some others, what ever you think might "Come in handy one day" to make up the cost.

Howard

Edited By Howard Lewis on 11/07/2022 20:19:02

.

Can’t be sure, but I would have expected the originals to have square heads and very slightly domed tips.

GKN made such things as a general stock item.

Back in the day, socket screws would be seen as too likely to fill with brass chips.

MichaelG.

Surprisingly, the originals were 1/4" BSW socket head cap screws (aka Allen heads). They seem to be high enough up that swarf does not fill them up.

I machine the ends flat then put on a very slight dome with a file then machine the OD down to about thread root diameter for the first 1/16" or less, so that if you ever want to take it out, the thread is not burred over on the end.

Note when buying new screws, the length to specify is the length of the shank only, not including the head.

.

That did surprise, and rather disappoint, me … but I was happy to take your word for it

… until I found the beautiful photo supplied by Bruce Stephenson on this thread: **LINK** 

https://www.model-engineer.co.uk/forums/postings.asp?th=170513

MichaelG.

Edited By Michael Gilligan on 12/07/2022 05:38:20

Photo taken 65 years after it left the factory. All the old photos show cap screws.

Edited By Hopper on 12/07/2022 06:23:48

Cap screws are the modern cheap way of doing it - adopted by the cheap-skates who manufactured machines down to a price. OK for those that blow compressed air around the place, spreading swarf and grit all over the place, I suppose.

Cap screws in that orientation collect debris very effectively. One reason why male bolt heads and female socket spanners were used in the past (apart from the fact tha cap screws were not common, or even available). Square headed bolts were also easily made by users.

You may not have noted that you never see anyone, on you tube, having to clear out the torx screw heads, when changing inserts on cutter holders?

The screws on my original chinese lathe 4 way tool post were not even machined to avoid thread-spreading issues! Talk about being cheap!

The post-war Myford approach to production engineering exactly. That is how the ML7 sold for less than its predecessor the M-Type. (Which used square-headed toolpost screws BTW!)

When I made the clamp screws for my 4 way rear toolpost, 1/2" bar was ideal for making the M10 clamp screws, The square head left a nice shoulder to replicate the clamp screws in the front toolpost..

This allows the same wrench to be used on both posts., to clamp tools.

I would be tempted to make my own eight square headed clamp screws.

Making the screws from 10 mm bar should mean that a square headed 1/4 BSW clamp screw would have a shoulder 0.040" ( 0.020" a side ) larger than the thread.

Lets hope that the OP has the ability to do this!

Howard

GHT considered cap screws to be acceptable for this purpose. Chips in the hex recess have never troubled me but I do use a ball-ended driver. Another reason to use cap screws would be losing the square key!

Someone mentioned that cap screws were prohibited in coal mines except where they were installed upside down.

If you have ever worked around coal you would know why! Horrible stuff. The dust/grit gets in everywhere and yes would fill up a cap screw.

Seems like all the old Myford factory literature has the "Dutch shoe" type toolpost featured. But Sparey's book A Man and His Lathe shows what looks like a Myford supplied retouched photo of a four-way, which the caption says is a genuine Myford accessory, and it has cap screws.

My impression is that QCTP tool holders generally use hex recess clamp screws and they have an army of fans.

If replacing the screws, I'd go for flush fitting grub screws so they don't stick up. That's something I've been meaning to do to all of my QC holders for some time. Picking grot out of the internal hexes when I loosen them every few years doesn't matter, whereas they do collect swarf every time they're used.

With a QCTP the holder can be inverted and tapped on the bench to clear chips from the sockets but a four way is not so easy. A sacrificial bit of plasticine or blu tac will clear the chips but bin it after use. Compressed air is effective but apart from the chips going where you don’t want them on the machine they are near certain to go in your eye even if wearing safety specs, even closing your eyes may not work as when you open them the chips stuck to your eyelid fall in your eye. My first choice would be to hunt down some square headed screws but that may not be so easy, remember that 1/4 UNC is often a passable alternative to 1/4 BSW and in this application will not be critical

Mike

Why are square headed screws used anyway and not hexagon headed? I've always thought the latter are easier to obtain and use with more spanner positions available, especially if using a bi-hex wrench. is it just historical?

John