Myford S7 saddle lock

[Allen Smithee]

So there I was, turning a special suspension bushing for a colleague's son's racing kart. It was just a bit of 40mm ally bar, and 'd already done the precision part of boring the recess for the pressed-in ballrace and just needed to part it off. There was a fairly close tolerance needed on the overall length and trueness of the back face, so I thought I'd try achieving all of this in one operation by using a really sharp parting tool in precisely the right place rather than all the faff of parting over-length, reversing it in the chuck and re-establishing the datum to face it to length.

Sf course rule 1 is to lock all axes you're not using, init? So I put the spanner on the myford's saddle-lock bolt and nipped it up. This is a 5/16BSF bolt with a flanged hex head, or at least is WAS. It's now a 5/16BSF bolt with a flange - the "hex head" part just sheared off, leaving my saddle locked and with no means to unlock it.

"Oh my golly gosh" I said (or something like that - the workshop voice recorder seems to have run out of tape) 

Fortunately the ~30thou of flange gave me just enough material to be able to make two careful side-by-side hacksaw cuts that took a decent screwdriver blade, and the decent screwdriver had a hex on the shaft so that I could put a spanner on it to release the bolt. So now I just have to make/buy a replacement.

But how on EARTH did I manage to shear the hex head off the flange of a flanged hex-head bolt, with just one hand on a stubby spanner?

 

AS

[Firebird]

Hi Allen

I made this for my ML7 from a bit of stainless bar. Saves the hassle of looking for the spanner

Cheers

Rich

[steamer]

I'm going to put a ball lever on my SB as I hate looking for the Allen wrench....


In the meantime....stop eating your Wheaties Allen!....


Dave

[zeeprogrammer]

This is timely.
Firebird's photo is what I was talking about on "Ye-Old Steam Dude"s thread when he got his new mill.
I have two very similar looking locks for the X travel (on the right side, under the table).
These things are driving me nuts!
The handles rotate very freely.
When I unlock them, the handles may drop down or onto the base.
Setting them at 90 degrees doesn't always help or is very easy to forget.
The result being, as I move in X, the handle may dig into the base or collide with a bolt holding the base to the table.
I'd appreciate any thoughts on this.

A couple of more questions...

There are two locks for Y and two for Z. They are the common handle/spring that you pull, rotate, release (to loosen) or then turn again to tighten.
Sometimes when I pull and rotate, the lock itself will turn when I don't want it to and it becomes a two handed operation.
Ideas to improve this would be helpful.

Lastly, as I mentioned, there are two locks per axis (and one for the quill). Do you always use both to lock? Or are there cases when one is sufficient. It's often difficult to get one.

With respect to Allen's, I too often have a Wheaties issue. How tight is too tight? Are the gibs being damaged? I really have to oomph it on the quill lock to ensure it doesn't move when the cutter hits.

Apologies if all this sounds very elementary but I don't recall seeing much discussion on this subject.

[Allen Smithee]

Hi Allen

I made this for my ML7 from a bit of stainless bar. Saves the hassle of looking for the spanner

I know what you mean, but I never have any trouble finding the spanner because it's the same one that is used on my QCTP. I've looked at the hemingway saddle-lock handle mod in the past:



But I don't like having things sticking up there where they can be in the way for my ball-turning fixture or my milling slide.

AS

[Stuart]

Allen

Could not agree more

BTW your lucky yours is a ml7 Those handles won’t fit a super7 /big bore as it’s at the front and fouls the under side of the top slide when set over

Don’t ask how I know

[Allen Smithee]

Actually mine is an S7(B), so it would foul - thanks for the warning!

I was looking on the myford spares website and note that for a mere arm and two thirds of a leg (£3.50+VAT) they will sell me a new bolt, but the one illustrated is a simple hex bolt with a full-sized hex head rather than the flanged, reduced-hex one that has just succumbed to my wheato-enhanced finger muscles. Are they just being cheap, or is this a redesign due to failures in the originally-specified part?

The price of that single bolt is *so* outrageous that I am tempted to make a replacement from silver steel. Ridiculous, I know - but I hate being taken for a mug and it brings out my stubborn streak!

AS

[pgp001]

I use a socket cap screw in mine and just leave the key in it all the time, the key has been shortened slightly at the end where it fits the screw.

Phil