Thread: Machinist's Screw Jacks

A couple of weeks ago Greg Q was in town and he gave me a number of German delicacies amongst which was a pair of DIF screw jacks. I had call to use one of the jacks yesterday while drilling a couple of holes in a replacement threaded collar for the tool and cutter grinder's workhead. I had used my bitty Hercus dividing head because the jaws on one of my chucks were small enough to fit inside the collar's bore and that chuck would only fit the Hercus. Problem with the Hercus is the swivelling head is fixed to the base with one piddly 3/8" BSW bolt. Downward drilling pressure could be enough to push the head out of alignment with the leverage afforded by having the collar mounted a fair distance from that 3/8 bolt.

I have other screw jacks. Those made by Starrett have a pivoting head which wasn't suitable for the support required. The DIF was.

Pretty simple construction. A search on German Ebay for Schraubbock will reveal a number made by AMF. I had no luck looking for DIF.

Thank you Gregory.

BT

Rough buggers, shouldn't that be a buttress thread?

I really should try my hand at making some of those as when I need them I cobble something together and then forget about it until the next time.

Do you need to add a demagnetiser to your collection?

Stuart

Originally Posted by Stustoys

Rough buggers, shouldn't that be a buttress thread?

I really should try my hand at making some of those as when I need them I cobble something together and then forget about it until the next time.

Do you need to add a demagnetiser to your collection?

Stuart

Well, I've had a dinky cheapo Chinese demagnetiser loitering in my eBay saved items for a few months, thinking that one day I might find a use for one. Now that I have a mag chuck for the T and C grinder, residual magnetism may become an issue. ( A question for magnetic chuck users, is it? )

Could you please provide me with more details Stu.

BT

Hi Bob,
I have not had any issues with residual magnetism so far. I have not left anything on the grinder for longer than the time it takes to grind it though.
I need one more for tools, my 6" etalon dial caliper seems to have become slightly magnetic

Nice jacks, making some are on my list. Never thought about using a square or acme thread though.

Ew

Originally Posted by Anorak Bob

Could you please provide me with more details Stu.

The demagnetiser I use most is an old Arlec tv degausser. Works well enough on small stuff. I'm pretty sure I have a spare like the below kicking around, hardly worth the post though. Coming over soon?

[US$13.06] - Color TV Magnet Exterminator (Green) : FancyCost - Cool Gadgets at Low Price - Worldwide Free Shipping

I also have a small motor with the rotor removed that works well.

Nothing flash........ just move the magnet and the work apart.


Stuart

Bob
Never really had any problem with residual magnetism off the surface grinder.
regards
Bruce

Originally Posted by Stustoys

Rough buggers, shouldn't that be a buttress thread?

I really should try my hand at making some of those as when I need them I cobble something together and then forget about it until the next time.

Do you need to add a demagnetiser to your collection?

Stuart

g'day very nice.
buttress thread stu. do you think. any one cut a buttress thread?
aaron