Help with drill-Mill conversion

[Ross77]

Ok feed up with messing around and decided to take the advice of you guys (think it was the 2nd or 3rd post) and buy a compound table...:clap:

Got this one
http://www.axminster.co.uk/product-A...able-21825.htm

Free delivery is a bonus. Bit of work and it it should be ok. T slot tables of the same size where the same price, so at least I will have a decent table. If it works I will have only spent £100 as the drill was free and the other tools are useful for other projects

Extra long tap and suitable bolt also on order. Hoping it will all be here for the weekend.

[Ross77]

A problem I've noticed with cheap tools is they aren't always the size they claim....

Problem solved, new tap cut like a hot knife in butter. Wont be buying any more tools from Machine Mart...........

Compound table is useable after all lot of rework. (Think it was cast, rough milled and bolted togother)

The bit I'm struggling with is eliminating backlash in the acme screw. I've Cut a slot and fitted a pinch bolt, but as the screw and thread are so rough the friction caused is not good.

My question is how critical is it to completly eliminate backlash or is the compensation in Mach able to overcome it?

I can probably improve the current state (about 2 or 3 deg. as a guess) but will take more time...

Photos soon If anyone is interested

[Robin Hewitt]

My question is how critical is it to completly eliminate backlash or is the compensation in Mach able to overcome it?

This rather depends on the accuracy you are trying to achieve.

The software can add extra travel when you reverse direction but that means the slides have to be tight enough to resist side forces from the tool so only the nuts can move them. Once the slides are set tight you have to worry about spring in the system.

Alternatively use two nuts. If you lock them together then wear becomes your problem. Spring them together with sufficient force to resist the tool pressure and you need monster size motors to turn 'em.

If it was easy to eliminate backlash with cheap screws nobody would sell expensive screws