Making timing pulley - putting theory into action

[Jonathan]

Impressive that your router is rigid enough for that. I did mine on the milling machine using the same process and it clearly put a lot of force on the spindle.

This time I used fly-cutter and rotary table.

I believe the term is form tool. Not that it's really matters...

Personally I would recommend this method than tooth drilling- less hassle - better tooth shape/finish.

I agree entirely. I found it difficult to get a perfect mesh with the belt. The theoretical values for the pulley blank diameter never seemed quite right.

[wiatroda]

Impressive that your router is rigid enough for that. I did mine on the milling machine using the same process and it clearly put a lot of force on the spindle.
I believe the term is form tool. Not that it's really matters...
I agree entirely. I found it difficult to get a perfect mesh with the belt. The theoretical values for the pulley blank diameter never seemed quite right.

I think it is rigid. Whole construction is milled from 6mm thick steel plate + 100x50 rectangular profile. After I paint it I'll make some pics.

hmm,maybe fly-cutter does not apply entirely. Anyway It's ground from broken end mill to create tooth profile or rather between-tooth-profile . My cutter rests safely and wait for next job .
Calculations worked for me:
pulleys PCD radius - 0.381mm gives you pulley radius.
then cut depth if 1.21mm.
However I found slight dimensional variations for pulley dia /doc. I used those from pic uploaded

[Jonathan]

I have only done XL series pulleys, so trapezoidal not round. Looks like it's easier to get it right with HTD. Should start replacing mine on the router.

JohnS' makes mine look a bit amateur:





As those went on my router they've had a lot of use and the pulleys under where the belt runs has got polished. Same is true for the bought ones. I wonder if it's worth anodising them to harden the surface? Would have to be careful not to change the dimensions too much in the process.

[wiatroda]

I have only done XL series pulleys, so trapezoidal not round. Looks like it's easier to get it right with HTD. Should start replacing mine on the router.

Does somebody buys the pulleys??? :lol:
The only issue I encountered was to set mandrel center in RT. After bit of playing with DTI I managed to set it up.

[Jonathan]

Does somebody buys the pulleys??? :lol:

I got a selection of XL cheap on eBay ... other than that, no I don't buy them.

The only issue I encountered was to set mandrel center in RT. After bit of playing with DTI I managed to set it up.

I did the same. Since it's a 3 jaw chuck I just did the bolts up not quite fully and tapped it into position.