Sourcing acme screws from junk

[franco2ke]

Hi! AM jus wondering which machines usually have acme screws or lead screws so that I can go looking for them in the junk market instead of buying new ones,

Any ideas of such devices and tools might help, I was thinking old woodworking machinery, but its a little hard for me to find such junk, anyone know any common appliances with mechanical parts that i can use for a benchtop PCB mill??

[High Seas]

You can find one in most Trash Compactors - very short - 12 to 18 inches - heavy duty like maybe 3/4 inch diameter and probably not a great pitch -- BUT almost Free! Good Luck! And welcome to the CNCZOne!
Jim

[Weldtutor]

Originally Posted by franco2ke which machines usually have acme screws or lead screws

Large (8' Dia.) older style satellite TV dishes usually have a 3/4" lead screw & nut about 30" long inside the position adjustment arm.

[keebler303]

some types of car jacks have leadscrews in them.

[martinw]

Originally Posted by keebler303 some types of car jacks have leadscrews in them.

Dear kebbler,

Well spotted!

Mine does, but I think that getting hold of a matching nuts might be a problem. Also, I cannot imagine that the jack makers put much thought into the screw accuracy.

It might work though.

Best wishes,

Martin

[franco2ke]

I actually got a lead screw and matching nut from a screw jack, some jack mechanic hacked it for me so well that he removed both the lead screw and the matching nut, as for the accuracy, I tried pushing it back and forth and I didn't feel any backlash because basically it wouldn't budge. I'm building a mill to make my circuit boards, so the Jack screw I have is apropriate for my Y axis. I hope the photos aren't too big, here they are

http://picasaweb.google.com/franco2k...68327064024162

http://picasaweb.google.com/franco2ke/PcbMill

I got the rods or from 2 old epson Dot Matrix printers and I will use them as rails for the longest axis on my mill the X axis, and its about 70cm or 2 feet long. the motors I got from a Junk market. I didn't know this but apparently bearings can slide along the rails pretty well, almost unbelievable.

[keebler303]

Originally Posted by martinw Dear kebbler, Well spotted! Mine does, but I think that getting hold of a matching nuts might be a problem. Also, I cannot imagine that the jack makers put much thought into the screw accuracy. It might work though. Best wishes, Martin

Martin, they should have some type of nut with them already. As for the accuracy, when you are considering trash compactors and satellite positioners, accuracy is not your first requirement. You get what you pay for!

Do a little screw mapping in mach and you are good to go.

Matt