Not just another machinist jack

[Frank S]

I really didn't have a need for another machinist jack but I did need something that I could use to mark a hole location
the hole is 41/64 ths and a 5/8 grade 8 bolt must be used so alignment is paramount
For this I really needed a transfer punch to mark the center but due to the location of the hole this was going to be next to impossible for all of the holes
SO this gave me the idea of using a machinist jack with a point like that of a transfer punch the only jacks I had are 2 small factory made and are hardened and I didn't want to modify them either so this is what I came up with
A jack made out of a piece of DOM tubing a 16MM 10.9 bolt and flange nut plus a piece of mystery metal shafting.
The jack in normal configuration also has a washer welded inside the bottom so it can be mounted via "T" slot to a mill using a short bolt and a "T" nut

Shown here are the jack base an extension the jack bolt and nut which are removable and the doweled transfer punch which can double duty as a locating dowel when multiple holes of the same spacing might need to be drilled by simply locating the previous hole on the locator dowel portion of the punch

Shown here is the machinist jack with the extension I have a thin jam nut not shown in the pics for locking the jack to height

Shown here as assembled with the extension and the doweled punch

Shown here with the jack nut inverted for reduced height

This is the location of 1 of 20 holes which must be located and drilled this one is one of the ones that I can actually see many of the others can only be touched or viewed by a mirror

Shown here is the jack in place with the punch in the hole a simple turn of a wrench will make a center mark

Inside of the chalk circle you can see the punch mark

The nice thing about this set up is I can machine any size dowel or punch needed