[martinw]

hey guys, I was wondering if it will be good enough to use a belt driven setup for my X rails?


-Dan

Dear Dan,

For what it's worth (probably not a lot), I looked into belt drives for a small CNC MDF frame 3 axis router last year. Like other people, a belt drive on both sides of the main bed seemed a good idea.

I came to the conclusion that the stretch of the belts under dynamic loads might be a bit of a problem. This was partly because I found it quite hard to relate manufacturers' figures of belt stretch ( if indeed they gave them) to the forces involved in a machine that accelerates etc.

Kipper is absolutely right, by the way, that open-ended belts are hard to find in the UK. You people on the other "side of the pond" do not know how lucky you are compared to us in "rip-off" Europe.

Best wishes

Martin

[Kipper]

Dear Dan,

For what it's worth (probably not a lot), I looked into belt drives for a small CNC MDF frame 3 axis router last year. Like other people, a belt drive on both sides of the main bed seemed a good idea.

I came to the conclusion that the stretch of the belts under dynamic loads might be a bit of a problem. This was partly because I found it quite hard to relate manufacturers' figures of belt stretch ( if indeed they gave them) to the forces involved in a machine that accelerates etc.

Kipper is absolutely right, by the way, that open-ended belts are hard to find in the UK. You people on the other "side of the pond" do not know how lucky you are compared to us in "rip-off" Europe.

Best wishes

Martin

:threadhijack ahead: I found a supplier called Wyko in the UK that can supply me with them Martin....For a price

[martinw]

:threadhijack ahead: I found a supplier called Wyko in the UK that can supply me with them Martin....For a price

Dear Kipper,

Thanks for that. I do not wish to sound ungrateful, but the belt stretch stuff could still be an issue. I'm pre-judging it, sorry. Will take a peek really shortly.

Thanks again..

Best wishes

Martin

[Kipper]

If anyone wants to express an opinion (I've been wrong before lol) and I'm actually on topic for once Attached is a rack type system that seems "awfully good" Very generous .zip file size allowed! :cheers: admin.

[ger21]

If anyone wants to express an opinion (I've been wrong before lol) and I'm actually on topic for once Attached is a rack type system that seems "awfully good" Very generous .zip file size allowed! :cheers: admin.

Make sure you're sitting down when you get the price.

[rcbamm]

Dear Kipper,

Thanks for that. I do not wish to sound ungrateful, but the belt stretch stuff could still be an issue. I'm pre-judging it, sorry. Will take a peek really shortly.

Thanks again..

Best wishes

Martin

I thought about the belt stretching.... but then, I'm only gonna be cutting mostly foam and balsa wood. once I get my table working properly and precise then I will try out some hardwood for firewalls and landing gear plates etc.. but if I can start cutting foam and balsa wood I will be a happy man

[ger21]

I thought about the belt stretching.... but then, I'm only gonna be cutting mostly foam and balsa wood. once I get my table working properly and precise then I will try out some hardwood for firewalls and landing gear plates etc.. but if I can start cutting foam and balsa wood I will be a happy man

Check out www.sdp-si.com for a lot of good belt info.

If you take a look at the threads from Joe's design router, they're all using or switching to 1/2-8 2 start acme. Best performance for the price, and easier to implement than a belt drive.

Just a guess, but I'd say at least 90%-95% of the homebuilt routers here use acme screws with great results.

With a belt drive, you'll likely need a gear reduction which adds to the complexity.

[martinw]

I thought about the belt stretching.... but then, I'm only gonna be cutting mostly foam and balsa wood. once I get my table working properly and precise then I will try out some hardwood for firewalls and landing gear plates etc.. but if I can start cutting foam and balsa wood I will be a happy man

Dear rcbamm,

I didn't wish to pour cold water on the entire idea of belt drives. Far better men than me have had good results.

If you take a peek into the guts of $70 ink-jet printer, you will see a tiny belt driving the print head. The print head sprays stuff with incredible accuracy.

Good luck,

Best wishes,

Martin

Martin

[randyf1965]

harryn,

Any pricing from http://www.brecoflex.com/?CATID=1&SC...T10&codeName=M ???

I want to do a belt drive is 3/8" wide enough for the y axis? MIne is 65" wide so I was looking at 3/4"

[harryn]

Hi - I have not asked for pricing yet.

The belt drive site has a calculation setup for belt selection - I have not run the numbers yet. I think it has more to do with how much force you need than Y dimension.

I made an guess (based on comments in threads by others) that the gantry would have a mass approx 50 Kg / 100 lbs, and be driven by at least a size 23 motor, or in my case, more likely a size 34 - so approx 400 - 500 oz - in of torque. Only logic is that is what other people seem to be using.

I am toying with using a really wide belt (2 x for each axis) so that the belt tends to help stabilize things, at least that is the idea - so I am thinking 3 or 4 inches wide. Probably way overkill, and the idea might die once budget reality starts to hit.