Giant 20' x 3' x 2' router build

[charlieuk]

vfd mounted and the aluminium plates to mount the y and z axis carriages and steepers , its been a bit of a jigsaw trying to fit it all but getting there.all so run some trunking and a few other bits and bobs.

still waiting on a gearbox to do the x axis and now just got to order some belts and pulleys to get the drives connected.

[charlieuk]

what are the best methods for tensioning timing belts on to steppers. I have slots for adjustment but need some sort of screw type adjuster to get the belt relatively tight. Cant seam to find much on here.

[EddyCurrent]

what are the best methods for tensioning timing belts on to steppers. I have slots for adjustment but need some sort of screw type adjuster to get the belt relatively tight. Cant seam to find much on here.

Section 10 page 45.
http://file.lasersaur.com/docs-third...ming_Belts.pdf

I just used the same technique as putting an alternator belt on, stick a large screwdriver in behind the motor and lever it out until the belt is at the 'correct' tension, now tighten the bolts.

[charlieuk]

i guess that keeps things simple! the pulleys i have have two grub screws for securing however the shaft is totaly round, whats best to do there? put a flat for them or drill a hole or something? cheers charlie

[EddyCurrent]

i guess that keeps things simple! the pulleys i have have two grub screws for securing however the shaft is totaly round, whats best to do there? put a flat for them or drill a hole or something? cheers charlie

Use two grub srews M4 will do, these MUST be 90 degrees apart around the pulley boss (i.e. NOT opposite each other). File a small flat on the motor shaft for one of these screws only. Where the flat is, use a flat bottom grub screw, for the other screw grind it to a point so it digs into the shaft once tightened.

[charlieuk]

cheers many thanks thats great will get on to that

[Clive S]

The way I have done mine is to put a copper plug (pad) into the grub screw hole. I have done this by using a bit of solid core earth wire from twin&earth cable just lightly swash it with a hammer and then cut a piece off that will fit down the hole so that the flat bit is on the shaft then just tighten the grub screws. That way you don't mark the shaft.
I have found that it is not necessary to put a flat on the motor shaft. ..Clive

[EddyCurrent]

The way I have done mine is to put a copper plug (pad) into the grub screw hole.

Im sure the locknuts for my ball screw BK blocks had a grub screw arrangement like that.

[Clive S]

Im sure the locknuts for my ball screw BK blocks had a grub screw arrangement like that.

Yes all mine did as well it's a common way of fixing as it does not damaged the shafts so that makes them easy to remove later if necessary. ..Clive