DIY Top and Cross Slide locks?
My 1960 Atlas 12 x 36 lathe has a carriage lock screw, but no lock screw on the top or cross slides. I was thinking of adding these for rigidity in some cuts, but was unsure of the best location for the locking screws. Is it better to put them on the sides where the adjustment screws are located? I was thinking that I could have a set screw press against spacer that rests inside the dove tails. If so, does position along the dovetail matter?
Any thoughts are appreciated.
Well I'd say don't put a locking screw anywhere else unless you can make very sure it wouldn't damage the mating surfaces...
The position would need to be where it would engage with the gib such that at both extremes of travel the lock is still between the mating surfaces and the gib.
I suspect mostly we just figure out which gib adjusting screw is 'center' and use it as the lock --I've just welded cross T's to the chosen set screw in some cases. Seems to work OK. Adding a dedicated lock would no doubt be better.
If you do add a dedicated lock please post some pictures of what you came up with, I know they would be of interest.
One of the gibs screws on my compound is longer than the others and it gets used as a (feeble) lock. Same with the cross slide though less feeble.
With straight gibs, it is a royal PIA to lock the slide by tightening the gib. Well, lets rephrase that: it is a pain to re-set the correct gib adjustment after un-locking it. So I can understand your wish to add a convenient lock. One option is to thread a blind hole into the bottom edge of the slide. Then make a larger tab in this shape: ⩍ Make a hole in the bottom portion near the flat. The top, rounded portion should extend over the edge of the top half of the slide. Now you can use a screw to tighten the tab against the side edge of the top half---in effect forcing the gib adjustment tighter without actually touching the gib screws.
Last edited by Arthur.Marks; 07-23-2012 at 01:45 PM.
George Thomas published a method of adding compound slide locks on the Myford. It seems to be very effective, as most of his designs were. The method used is roughly along the lines that Arthur.Marks describes, but in addition, he added a pin to stop the gib from moving along the axis of the slide. The two mods work well together. Might be worth a look for your Atlas.
I just replaced one of gib screws with some lock screws I made. The one on the compound was moved to the center and shortened by about half after the picture was taken. The one on the cross-slide is even shorter--About 3/4" long to give clearance for the tail stock when it's close to the cross-slide. Finger tight is enough to lock either.
Thank you all for the answers. Will get crackin' on some locks with the feedback given.
that is basicly what i did took one gib srew out and drilled and taped it 1/4 28 and used a thumb screw works great for a lock