Re: Chester 20v and G0704 comparison
Dear GarageCNC,
I Live in Scotland, and have recently bought the same Mill (Chester 20Vs.) am converting to CNC.Need help with sizes etc of the Ballscrews and the nuts.
i.e specification, lengths etc and how what support bearings you used.
Look forward to your kind reply.
Yours sincerely. Mechan6
Re: Chester 20v and G0704 comparison
This thread hasn't been updated in 8 years so getting info from OP might be tough.
I want to say that most people use a 16mm by 5mm (5tpi) ball screw on their G0704's. As for lengths I do not know, maybe ArizonaVideo or another poster with experience will chime in.
Re: Chester 20v and G0704 comparison
Quote:
Originally Posted by
Mechan6
Dear GarageCNC,
I Live in Scotland, and have recently bought the same Mill (Chester 20Vs.) am converting to CNC.Need help with sizes etc of the Ballscrews and the nuts.
i.e specification, lengths etc and how what support bearings you used.
Look forward to your kind reply.
Yours sincerely. Mechan6
If it's this one I would have avoided it and looked at Amadeal for a belt drive machine with R8 taper.
https://shop.chesterhobbystore.com/c...=7466463002671
As for ballscrews I don't know lengths but recommend using 1605DFU.
You'll have to measure it up and see what suits.
You could get them custom made at cost to fit the machine then just add your own motor/nut mounts.
If you go for the Chinese ones already end machined then you want to make your own bearing mounts too and fit 32x12x10mm AC bearings. Thrust bearings don't sit well on them at all.
Re: Chester 20v and G0704 comparison
On my PM-25 (very similar in size), I used 750mm 1605 double nut on X, 350mm 1605 double nut on Y, and 600mm 1605 single nut on Z.
Re: Chester 20v and G0704 comparison
Quote:
Originally Posted by
shooter123456
On my PM-25 (very similar in size), I used 750mm 1605 double nut on X, 350mm 1605 double nut on Y, and 600mm 1605 single nut on Z.
I would suggest to use 2005 screw for Z instead of 1605. This is what Hoss recommended.
Re: Chester 20v and G0704 comparison
Dear dazp1976,
Many thanks for your kind reply and advice, much appreciated.
I will look for the 1605DFU ballscrews.
And at making the bearings mounts to suit the 32 x 12 x 10mm Angular Contact Bearings.
Yours sincerely.
Mechan6
Re: Chester 20v and G0704 comparison
You can do 2005, no harm there.
From all the spec sheets I have seen, the 1605 will have a dynamic load rating around 600 kgf. With a 75lb head (standard weight was around 55 lbs, then air cylinder and heavier motor added), when accelerating upwards at 150in/s^2, the load will be around 462 N * coefficient of friction from the ways. 462 N is 47 kgf, meaning the 1605 can handle 12 times what is being asked of it. Unless my math is very wrong or I am missing something, the 1605 is more than sufficient.
Re: Chester 20v and G0704 comparison
I use 5/8" diameter, 0.2" pitch Thompson rolled ballscrews on all axes of my G0704. These are pretty close to the 1605 metric and they have never given me any problem. I'm going to be using a 2005 screw for the head on my RF-45. The RF-45 is a lot bigger machine and I even think the 1605 would be sufficient here, but there was not much price difference and plenty of room. On the G0704, cramming a 2005 ballscrew, nut, and mount into the little column is going to be pretty tight. If I were going to do another G0704 size machine I'd still use 1605 ballscrews on all axes.
Re: Chester 20v and G0704 comparison
For the RF-45 go ahead and run the 25mm. It will last longer.
Re: Chester 20v and G0704 comparison
Dear 109jb.
Many thanks for yours and everybody's advice much appreciated.
All I got to do is collate them all. work out the lengths.
Then find a supplier as I live in North Scotland.
Best wishes.
Yours Mechan6
Re: Chester 20v and G0704 comparison
Dear dazp1976,
Thank you for your advice.
As regards using the 1605DFU ballscrews.
Not heard of that classification, but will look it up.
I was thinking of using Two RK12 End support pre-loaded angular contact bearings on each end of the X Axis.
As one end is motor driven other has a the handwheel.
Thanks again, Best wishes.
Mechan6
Re: Chester 20v and G0704 comparison
Dear Stigoe,
many thanks for the advice concerning the 2005 Ballascrew for the Z axis .
My thoughts are inclining that way
As I live in N Scotland , got to find a supplier to suit.
Many thanks again.
Yours Mechan6