Denford Software & Machines

i agree with what you say as i have got my old gear cutting books out and using the formulae provided the drawing sizes appear to be correct.i can only suspect that the plastic [delrin] has distorted over time to create a more elongated gear tooth or some previos owner made there own gear causing the 100 thou od difference.the 10 thou shaving of the gear has definetley freed it up somewhat

this bvs 100/105 for the lay gear where is it.i have trawled through the sites but cant find it

It's right here!

Pete. wrote:It's right here!

Yes, thats the final version, incorporating the reductions in OD, PCD and width, following problems with binding.

many thanks for the diagrams.i think i am going to make one

the problem is definetley caused by by the technyl distorting over the years.only this can account for the expanded o. d. i have found on both gears.i have reduced both and this has helped will probably need to make new ones though

patrick oates wrote:the problem is definetley caused by by the technyl distorting over the years.only this can account for the expanded o. d. i have found on both gears.i have reduced both and this has helped will probably need to make new ones though

Its still a bit odd. I wouldn't have expected the gear to grow by 100 thou, were they both like that? That much oversize, how could they possibly mesh with the steel gears?

When they are cold they mesh fine. When hot you can barely move the handle on the front.

just to give an end to this,it was indeed the expansion of the technyl material.i took the layshaft gear out and using a friends milling machine and dividing head I shaved the gear down using a flycutter,a bit slow but it appears to have done the trick,so far it been working fine.i did have to shave agood bit off using drawings previously supplied

Patrick,

That's for the follow-up. It will probably help someone in the future.

Pete.