Re: [CAD_CAM_EDM_DRO] Ball-screws

Hi Jon,

I take your points and as usual you are perfectly correct.

These are rolled threads and are not anti-backlash nuts but the idea was
just to buy the thread and make up my own ends. I say the machine is
Bridgeport like, it is in fact, a Beaver and I doubt if the Bridgeport kits
will fit with out a great deal of work.

The cost of the nuts on the cheaper option from McMaster-Carr is only $32.00
and I thought that if I bought two for each axis I could make up an
anti-backlash nut.

Surely if the error is known it can be programmed out by the controller or
the CAD/CAM package, or even me as I do the drawing.

I only have about a week to come to a decision, my wife is in the States at
the moment and can bring them back with her thus avoiding shipping charges
and possibly the high taxes at this end.

To answer the other post from John here in the UK. I do not have a
controller at this time. I am in the process of putting together a system
based around servo boards from Jon, DC motors from a Philips washing
machines and encoders from the G9932 of Goldmine Electronics. I will be
giving EMC a go. The thing is if I try to do everything at once I will not
have the miller to aid the construction. It is an imperial machine and I
will have to rely on the dials for a while. I work in imperial and metric
with ease regardless of the dial readings but need a datum to start from.

I will chase up the leads you have provided, thank you.

Regards,

Terry




Are both of these anti-backlash ball nuts? Typically, the nuts cost
more than
the screws! These are not very accurate screws, that's for sure.

You should also check with Thompson (the linear bearing people) who
bought
Saginaw steering gear, who made a Bridgeport retrofit kit.

Also, try Ball Screws and Actuators, who make a kit for a number of
machines,
and HiWin, who also have kits. HiWin may have a higher precision kit
that
comes in cheaper than one of the above sets you already priced.

Jon


Terry,
Judging by the error and price I would say that these are rolled
screws and are not suitable.
Why do you worry about metric / imperial. The controller will take
care of that.
I have an imperial Beaver mill 0.200 pitch screws, imperial dials but
I work 100% in metric from the controller.

Places to try in the UK are Thompsons who are somewhere in Devon and
a company called Jenna Tec at Ilkeston Derbyshire 0115 99440446
Joe Gray runs this small firm and they actually make ballscrews there.
Often have recons in stock as well.


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