New machine bearing question?

[DRP]

Hi
I was just about to spend the best part of £3,000 today for a new German (router) machine, when I noted in one of the pictures that the support rail bearings looked a bit like slides. So a quick email off to ask and 2 hours later the answer came back (defensively) that they were all Bronze slides throughout the machine although I was paying extra for ball screws.

Now its my understanding, that Bronze slides are a cheaper option (due to wear issues) compared with ball bearing blocks etc although the supplier insists they are more accurate with better tolerance then the ball equivalent.

Could someone put me straight please, ie is this a sign of a cheap build or is it acceptable on this price machine ?

Its a typical “all Alloy” (off the shelf) open frame 4 motor type, approx 1 metre x 600mm in size with XY ballscrews and 20mm rails.

Many Thanks for any thoughts (before I part with the pennies)

DP

[NC Cams]

It is all in the execution.

Precisely fit/honed bushed guides can funtion slop free - I dunno about friction. Sloppy fit ball bearings can be lower friction and more slop if they are not properly zero clearanced or ever preloaded.

Preloaded ball bearings should be slop free and relatively low friction if executed properly.

I'd be disinclined to judge by sight - proof is in the performance.

Arrange for an in-person demonstration for best determination prior to buying.

[DRP]

Thank you NC Cams for your comments.

It's a tough one as this type of CNC are not in abundance in the UK, hence the need to buy elsewhere. With this fact in mind I am not going to be able to secure a demo without the expense of visiting another country.

It seems slides may not be as inferior as I thought.

Although up until I realised this issue I was pretty much ok with the manufacturer who proudly boast the accuracy with video’s of dial (clock repeatability) and rapid speeds (with ball screws) of 7metre's per min etc etc


I would however much rather buy a more serious complete kit, but do not have the time to scratch build or find companies to cut components to be able to build from plans. I do watch ebay every day, but its pretty dead for complete router tables at the mo (well at least the UK one is)

I will leave it to next week, to see if there are any more thoughts or if anyone can point to another supplier perhaps.

Thanks again

DP

[Oldmanandhistoy]

Hi DP,

Do you have a link?

It would be worth putting the machine up on the zone for comments as there are some very knowledgeable people here (one you have already met for instance) and they may have comments worth thinking about other than the linear arrangement.

John

[DRP]

Thanks John (why didnt I think of that)

I imagine this place will already be known to many as they advertise on ebay

There is alot of info vids etc via the links.

My interest is with the High Z/ 1000 (T) version which has the ball screws


Basic pages:
http://www.cnc-router-routers.com/ht...ter_engrav.HTM

T version page:
http://www.cnc-router-routers.com/ht...rews_cnc_.html

David

[Oldmanandhistoy]

http://www.cnczone.com/forums/showthread.php?t=11186