[JAy1st]

Hi all,

I'm new to DIY CNC (on the forum as well) and I was thinkinf about using the screws from a couple of Scissor Jacks.

Any inputs or doubts about the idea ?

[geoff p]

You might find that a length of Allthread (or whatever brand) is a cheaper option than destroying a couple of scissor jacks. Your local machine shop can remove the thread at one or both ends down to a suitable diameter for your bearings.
Choose a length that is decently straight, though, 'cos it will shove the nut/follower around something wicked if it has too much bend in the rod. Any attempt to constrain the beast will absorb power from your drive system.
Cheers,
Geoff

[p3t3rv]

Hi
the screw from a jack is designed to take massive loads and be cheap as chips they dont put much if any thought into linier accuracy but you never know its worth testing at least if your stuck for a thread, there is a shop on ebay that sells stuff specificaly for cnc and the prices are good i have shoped with them a few times look for

Marchant Dice Ltd

[JDW]

How about using a shoulder bolt and use a counter bore. you could modify it easily, it may have a mid range cost involved.

[FPV_GTp]

QUOTE=JAy1st;309823]Hi all,
I'm new to DIY CNC (on the forum as well) and I was thinkinf about using the screws from a couple of Scissor Jacks.
Any inputs or doubts about the idea ?[/QUOTE]

is a very good idea , found in nearly every vehicle on the road and many junk yards.

you may find some of the threads do have a lot of bend in them.

but yes you are restricted in length and some of the jacks i have pulled apart have 2 stoppers notched into the threads which again limits travel.

I have thought of welding up these notches and grinding them back and cutting the thread again in the repaired area.

Im making a very small cnc router table using jack threads , just for experimental reasons ( cost savings )

threads are good , just have to make a double locking backlash nut assembly to eliminate as much as possible the backlash in both directions.

cheers

[JAy1st]

I am only interested, for the moment, by a small system.
And from what I saw these screws match my needs.
They are ACME threads and some kind of "self locking design".

And have to make a double locking backlash nut assembly which seems to be mandatory.


Tnx for the replys !