1st Build, Steel, Epoxy 24"x24" for Wood

**Desertboy** · 09-03-2018

More importantly is that a Mustang in the rear of the photo? Camaro and Firebird man myself but could slum it with a mustang whilst I wait for a 67SS to drop from the sky or a 77 Trans Am ;)

The commercial printers we scrap always have tensioners on and the belt lengths are measured in inches (Short), if you can get tensioners easily enough than I'd fit them. They're sprung to apply constant tension and are adjustable.

**wallyblackburn** · 09-03-2018

Originally Posted by Desertboy

More importantly is that a Mustang in the rear of the photo? Camaro and Firebird man myself but could slum it with a mustang whilst I wait for a 67SS to drop from the sky or a 77 Trans Am ;)

It is actually a '65 T-Bird. I went to an auction with the intention of buying a '63 Impala SS, and somehow came home with that over-engineered POS. Auction fever, I guess!

I think I will try to fab up a tensioner for the top span.

Regards,
Wallace

**m_c** · 09-03-2018

I'd try the setup as is. The worst case scenario is the belt flaps far too much and causes resonance problems, and you then have to add some idler pulleys.

If it does need a couple idlers added, I would probably add a couple rollers to the top, to drop the belt down in the middle and increase wrap on the ballscrew pulleys.

**wallyblackburn** · 09-03-2018

Rigged up a tensioner using stuff on hand - including a Subaru timing belt idler bearing:

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**wallyblackburn** · 10-03-2018

First movement!!!

**Clive S** · 10-03-2018

First movement!!!

I don't think it will cut anything without a Z axis

**JAZZCNC** · 11-03-2018

Originally Posted by wallyblackburn

First movement!!!

Thats not movement that's a twitch.!. . . . Let it have it's head to shake the gremlins out.

**JAZZCNC** · 11-03-2018

Originally Posted by wallyblackburn

Rigged up a tensioner using stuff on hand - including a Subaru timing belt idler bearing:

Be careful not to over tension because will deflect the ball screws causing whip when at opposite end of travel. It would have actually been ok without a tensioner thou it's better down out of the way.

**wallyblackburn** · 11-03-2018

Originally Posted by JAZZCNC

Be careful not to over tension because will deflect the ball screws causing whip when at opposite end of travel. It would have actually been ok without a tensioner thou it's better down out of the way.

Interesting. I’ll back off the spring pressure and adjust as needed when it’s actually working.

Thanks!

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**Davek0974** · 11-03-2018

Originally Posted by wallyblackburn

Interesting. I’ll back off the spring pressure and adjust as needed when it’s actually working.

Thanks!

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Yes, that long run of belt, I would have probably around 10mm of easy deflection in it - you really do not want to "twang" timing belts like guitar strings ;)

As long as they are not flapping in the breeze, the tension does not affect accuracy as much as you might think, but it will wear things out, cause resonance and generally not be good.