1.7*0.74*0.4m Mill / Router building...

[Jonathan]

Just got some M16 threaded rod for the Y-axis, thought I'd give a quick demo of the drive 'nut' as it's a little different...



I know I should probably use ballscrews, but I reckon using this method is almost as good - rolling friction, low backlash... I measured the backlash on the plywood Z-axis I made using this method and it was <0.005mm which I think is pretty good considering the cost!

I guess it'd be better to use trapezoidal and put an insert in the bearing to fit the thread better - I'll leave that for a later date though.

[Wobblybootie]

Now that got my attention ... have you detailed it elsewhere?

[Jonathan]

Now that got my attention ... have you detailed it elsewhere?

Haha, thought it might!

I've not detailed it elsewhere, shall I start a new 'thread' about this?

[TrickyCNC]

Very nice machine you have there Jonathon !did you get anywher

e with the 'twisted bearing' screw drive setup ?

Rich

Just got some M16 threaded rod for the Y-axis, thought I'd give a quick demo of the drive 'nut' as it's a little different...



I know I should probably use ballscrews, but I reckon using this method is almost as good - rolling friction, low backlash... I measured the backlash on the plywood Z-axis I made using this method and it was <0.005mm which I think is pretty good considering the cost!

I guess it'd be better to use trapezoidal and put an insert in the bearing to fit the thread better - I'll leave that for a later date though.

[Jonathan]

Very nice machine you have there Jonathan

Thanks, but it's not that great really...quite a few things I'll be changing as the gantry is not strong enough for what I want to do next.

did you get anywhere with the 'twisted bearing' screw drive setup ?

Yes, I mounted it and it worked well with low backlash:
http://www.mycncuk.com/forums/router...html#post16838

It's clearly not as good as a real ball-screw, but as something to get started it's excellent due to the low backlash and very low friction.

I cut the first piece with the new bed last night - just a pocket in the back of an aluminium motor mount and the finish was much better than with the [edit] MDF bed and I didn't need to do a finishing pass to get that.

[TrickyCNC]

Yes, I mounted it and it worked well with low backlash:
http://www.mycncuk.com/forums/router...html#post16838

It's clearly not as good as a real ball-screw, but as something to get started it's excellent due to the low backlash and very low friction.

I saw you have mounted it, what I could not tell from reading the rest of the thread, is if you kept it / still use it ? and if so, how it was holding up ?

Rich

[Jonathan]

I used it for quite a long time, until changing to an RM1610 ballscrew. It was working well, although had caused some wear to the M16 rod (although not enough to be a problem) due to bearing inner ring being significantly harder than the screw, however I think if you used springs to push the angled bearing against the screw and/or used a trapezoidal lead-screw instead then it would last a long time.

[JAZZCNC]

I cut the first piece with the new bed last night - just a pocket in the back of an aluminium motor mount and the finish was much better than with the aluminium bed and I didn't need to do a finishing pass to get that.

Surely that should read MDF bed.?

[Jonathan]

Surely that should read MDF bed.?

Yes, thanks for pointing that out - fixed.

What size fly cutter do you use for surfacing yours?

I'm cutting the aluminium angle now to fit round the sides for the coolant barrier, then once I've got the bed aligned I'll get the router to cut a suitable hole in the bed at one end for the coolant to flow through and make a filter etc...

I seem to be able to cut 3mm per pass with the 6mm single flute cutter now :)

[JAZZCNC]

What size fly cutter do you use for surfacing yours?

It's a special that someone made for me and it's widest is 60mm.

I seem to be able to cut 3mm per pass with the 6mm single flute cutter now :)

Yep surprising how much a nice solid bed changes how the machine performs and best of all it never changes it's shape when you put your cup coffee near it.!!