[photomankc]

Yeah I had gotten rid of the bellows back when it was still manual. I don't remember however doing anything to the casting when I put in the Y ball screw. Maybe I'm just remembering wrong because it does seem like it's the mount that stops the travel. I say that because it is a hard stop. It goes right to that point and not a step further.

I guess you could add a bit of Y with a spacer at the column and then one at the head like you have done. Just keep running into a few places in my robot design where another 1" of Y travel would make life so much easier. I'll look under there the next time I break it down and see if there is any interference going on.

[hoss2006]

You'd need to open up the slot on the base to get more than 7 inches Y too, same reason, the ballnut mount hits the slot ends.
Hoss

[hoss2006]

I got a quote from Nook for their XPR ballscrews and nuts that would work for the G0704 CNC conversion. (06-20-2012)
The sales dept head gave me a call. Listed are prices for 4 feet of 5/8 ballscrew and types of ballnuts for use on the X and Y axis as well as 2 feet of 3/4 ballscrew and types of ballnuts for use on the Z axis.
These are precision rolled ballscrews with a lead error of only +/- .001/foot.
Note: You'll need (2) 5/8 ballnuts (X and Y) and (1) 3/4 ballnut (Z) in the type you like.


X and Y Axis
4 feet XPR6320R48 5/8 ballscrew - $104.05
SGN10083: SGN Non-Preload nut - $504.17
PRN10106: PRN Preloaded Nut w/out Wipers - 408.30
SSN0389: SSN Preloaded Flanged nut - $693.10
SSN10274: SSN Preloaded Internal Return nut - Discontinued
SSN10304: SSN Preloaded Flanged Internal Return nut - $1010.95

Z Axis
4 feet of XPR7520R48 3/4 ballscrew (request custom length cut 2 feet to save $) - $199.95 ($99.98 2 ft.?)
SSN0390: SSN Preloaded Flanged nut - $883.47
PRN10109: PRN Preloaded nut - $759.21

Cheapest price for full conversion - $1779.84 plus shipping

Most expensive flanged nut package - $3109.40

As a comparison, chinese C7 package (.0018/ft) machined ends shipped for less than $250.

[hive8]

Thank you HOSS for the research on this, that are some hefty prices... for that price you can almost buy a new mill converted already .

Did you get the Linear Motion 2008 ball screws already for a test? I am going to hold off a little on getting it, till i see a review from you.

[hoss2006]

I've got a 1605 C7 screw and nut on order from linearmotion but nothing on tracking yet.
I'll check the same balls in it when it arrives. Might be a week?
Hoss

[hive8]

Sure thing i have time till then, just use my ACME screws for now then do ball screws right after...

[cjsamples]

Hoss,
Does the ebay shop have a kit all set up for the 0704 or do you piece part it?

Thanks, Chris.

[hoss2006]

I haven't seen any titled for g0704 or bf20, best bet is to email him and ask for what you want.
RM1605 x 350 (stock Y travel front mount)
RM1605 x 800 (X axis)
RM2005 x 600 (Z axis)
Hoss

[cjsamples]

Thanks for the info. If I do the conversion I think I will go with the extended travel on Y and Z. It is always better to have it and not need it than not have it.

Chris.

[SCzEngrgGroup]

I got a quote from Nook for their XPR ballscrews and nuts that would work for the G0704 CNC conversion. (06-20-2012)
The sales dept head gave me a call. Listed are prices for 4 feet of 5/8 ballscrew and types of ballnuts for use on the X and Y axis as well as 2 feet of 3/4 ballscrew and types of ballnuts for use on the Z axis.
These are precision rolled ballscrews with a lead error of only +/- .001/foot.
Note: You'll need (2) 5/8 ballnuts (X and Y) and (1) 3/4 ballnut (Z) in the type you like.


X and Y Axis
4 feet XPR6320R48 5/8 ballscrew - $104.05
SGN10083: SGN Non-Preload nut - $504.17
PRN10106: PRN Preloaded Nut w/out Wipers - 408.30
SSN0389: SSN Preloaded Flanged nut - $693.10
SSN10274: SSN Preloaded Internal Return nut - Discontinued
SSN10304: SSN Preloaded Flanged Internal Return nut - $1010.95

Z Axis
4 feet of XPR7520R48 3/4 ballscrew (request custom length cut 2 feet to save $) - $199.95 ($99.98 2 ft.?)
SSN0390: SSN Preloaded Flanged nut - $883.47
PRN10109: PRN Preloaded nut - $759.21

Cheapest price for full conversion - $1779.84 plus shipping

Most expensive flanged nut package - $3109.40

As a comparison, chinese C7 package (.0018/ft) machined ends shipped for less than $250.

That doesn't appear to be an apples-to-apples comparison on the nuts, though I haven't looked up what those numbers map to, but the prices are WAY above what I paid. The ballscrew stock prices seem in-line with what I paid, so I doubt the overall pricing has increased all that much since I bought mine. For reference, what I ordered for my knee mill (in Jan. 2008), was:

1 18" 0631-0200 XPR RH $40.78 = $40.78
1 60" 1000-0250 XPR RH $246.70 = $246.70
1 24" 1000-0250 XPR RH $98.68 = $98.68
2 SBN10325 $33.73 = $67.46
4 SBN10466 $49.36 = $197.44
Total = $651.06

The SBN10325 are 5/8", the SBN10466 are 1". These are single, non-preloaded, single-circuit round nuts, comparable to those sold by Roton, etc., but higher quality. Based on these prices, the whole G0704 kit should be under $400, which seems to me a reasonable increment given the greatly increased accuracy, and higher overall quality.

Of course, add to that the cost of getting the screws machined, because that XPR stock is hard as diamonds! I sent mine out to a specialist for machining, which cost me another $350 including round-trip cross-country shipping via FedEx (for a 5+ foot long box at that).

Overall operation of the XPR screws, even with the "cheap" nuts I used, cannot be compared to the other rolled screws - the smoothness and quietness are virtually on a part with ground screws.

Regards,
Ray L.

[hoss2006]

Well there's a big price difference because you are using the wrong ballnuts for XPR ballscrews, you are using SRT ballnuts which are for standard rolled screws with .004 lead error.
I gave the link to their webpage and it has all the ballnuts listed for the type of ballscrews.
As far as machining goes some of us are specialists or know specialsts or they have the option of Nook machining them.
Also, the prices I was quoted are comparable to a quote I got from Nook in 2009 for similarly sized screws and nuts for
the X2 as seen on this page. http://www.hossmachine.info/Shop_Inf...w%20and%20nuts
Hoss

[rayross11]

Wow, expensive nuts. I stopped by the Nook booth at the Automation show in Chicago today. They have a new line of metric ball screws. They also had some ball screws that were permanantly mounted into steppers. They had nema 17 stepper with a 8mm ball screw that went all the way through the stepper, the nut was inside the motor. I didn't ask about pricing, just thought it was intresting.
Ray

[SCzEngrgGroup]

Well there's a big price difference because you are using the wrong ballnuts for XPR ballscrews, you are using SRT ballnuts which are for standard rolled screws with .004 lead error.
I gave the link to their webpage and it has all the ballnuts listed for the type of ballscrews.
As far as machining goes some of us are specialists or know specialsts or they have the option of Nook machining them.
Also, the prices I was quoted are comparable to a quote I got from Nook in 2009 for similarly sized screws and nuts for
the X2 as seen on this page. Shop Info
Hoss

There is no "wrong" ballnut for XPR screws. Most people using them would opt for the more expensive, pre-loaded nuts. But I chose, on the advise of a Nook application engineer, to use the standard SRT single nuts, and spring pre-load them. Lead error is determined entirely by the screw, not the nut, so this has no impact on accuracy. Using the nuts I did will slightly reduce the load capacity, but not enough to have any adverse affect on a machine outside a commercial production environment.

Nook, BTW, quoted over $500 PER SCREW to do the machining.

Regards,
Ray L.

[hoss2006]

Yes you can use sloppy nuts if you have room to double nut like on an rf45 or kneemill but
we're not talking about those mills here, this is a discussion about the g0704.
No way would I bother going with XPR screws on the g0704 and use a single sloppy nut.
I'd use the XPR nut to fit in the confined areas.
I have a quote in the works from Hiwin too that has a similar very low lead error ballscrew.
Hoss

[hoss2006]

Wow, expensive nuts. I stopped by the Nook booth at the Automation show in Chicago today. They have a new line of metric ball screws.
Ray

Yeah that page is here.
Rolled Ball Screws. Ball Screw Assemblies
These PMT's are similar to the XPR's for lead error and basically the same as the ones from Hiwin I was looking at too.
Don't think any of them can compete with the C7's from linear motion as far as best bang for your buck.
Hoss

[hoss2006]

It was asked in this thread if anyone knew if linear motion on ebay could cut down the flange on the x axis ballnut.
http://www.cnczone.com/forums/bencht...ersion-10.html
I emailed Chai last week and sent him a print but he said they couldn't do it.
Well I just got another email and now he says they can cut it.
He didn't give a cost so I asked about that now.
More later.
Hoss

[hoss2006]

Well that was a fast response, Chai says the cost to cut the flange on the X ballnut will be $6 usd.
Total cost of that plus the 3 ballscrews and nuts with machined ends, $209 usd shipped.
Can't beat that.
So if you ask he will cut it.
Hoss

[Connor]

Well that was a fast response, Chai says the cost to cut the flange on the X ballnut will be $6 usd.
Total cost of that plus the 3 ballscrews and nuts with machined ends, $209 usd shipped.
Can't beat that.
So if you ask he will cut it.
Hoss

Good deal. I wonder if he's doing it BEFORE or AFTER the balls are loaded into the nuts?

[Connor]

Hey Hoss,

There has been some talk in other threads about wire management, E-Chain, Wire-loom, and cable management on the Mills. Care to post a few pictures showing how yours is done and make a few comments and give some insight on your trials and tribulations of what you've tried in the past and what your doing in the present?

I have some left over E-Chain I might use for the Z-- Wire for motor, encoders, and future use for coolant/air or whatever.

Thanks, Connor

[feederic]

Well that was a fast response, Chai says the cost to cut the flange on the X ballnut will be $6 usd.
Total cost of that plus the 3 ballscrews and nuts with machined ends, $209 usd shipped.
Can't beat that.
So if you ask he will cut it.
Hoss

That is a great deal! Is he cutting the flange flat, and just lowering the flat shelf? I recommend cutting away as much as possible on the outer ends of the flange away from the setscrew, this will reduce any table grinding you may have to do since there will be less area for interference.

Keep in mind people, eventhough the ballnut flange is cut down, there may still be interference with the rough underside casting of the table. A $15 4 1/2" angle grinder from HF makes quick work of the iron. I spent most of Saturday grinding away on my table, and will hopefully finish up this week.