On Monday, July 18, 2016 at 11:55:08 AM UTC-5, David Billington wrote:
On 18/07/16 17:27, Ken Grunke wrote:
On Monday, July 18, 2016 at 3:54:59 AM UTC-5, David Billington wrote:
On 18/07/16 02:46, Ken Grunke wrote:
Does anyone know, or know where to find online, the specs for the pulley
that a J-series belt would fit on? ...

Kind of odd that Amish can use their English neighbor's phone but not have their own - and very inconvenient at times!
Continental have a good design guide here
https://www.contitech.de/pages/produ...irib_de_en.pdf
. You should find the details you need such as spacing, V angle etc in
the first 12 pages or so.
Awesome, thank you. I got the groove angle right, 40 deg. but the spacing is 2.34 mm, a little off from my 2.38 mm, the decimal equivalent of 3/32". And that's 1/100th of a millimeter outside the permissable range of error. I'm using the 16 tpi lead screw to space the grooves, with an index pin into a large gear. I wonder if I can continue with that spacing, without problems. The client is happy with it so guess I am too.
Here's a couple shots of what he's doing:
https://i.imgur.com/o44cvan.jpg
https://i.imgur.com/JryOshE.png

Looks neat and handy to have so that Amish person has adopted some
modern conveniences but I guess no electricity hence the engine.

I've made one 6 groove J pulley for a motor to drive a flat lap disc.
The disc was mounted onto a VW rear stub axle and drum assembly and the
drum OD was machined as standard so the poly V ran directly on that.
IIRC somewhere in the design guide it mentions if the driven is more
than IIRC 10x the driving pulley diameter you don't need the grooves and
can run the belt on a cylinder and treat it like a flat belt. My lathe
has a DRO so the spacing was easy and I made a single point tool for the
job, worked well.

I should get me one of dem DRO thingies. The lead screw method was a pain in the ass, mostly due to slop between the half-nut and screw. I messed up 3 blanks of 2" dia. x 1 3/8" long alumninum before I got it right but they can be used somewhere else. Here's my semi-crude indexing setup on my Emco Maier Compact 8:
https://i.imgur.com/EQpS6Kw.jpg

I made sure to turn the leadscrew in one direction only. Then after locking the pin in the gear, I nudged the carriage wheel over to take up any play and locked the carriage for the cut.

I used a single point tool also. Set the compound at 20 deg. so I could cut just the left face of the groove, like a threading tool. One way I messed up the earlier tries was by feeding straight in. I did practice runs on 3/4" shaft first, but got overconfident early (and impatient)

I drilled and tapped 2 setscrews 90 deg. apart so I could mount the blanks on an arbor to get most of the work done.

https://i.imgur.com/lb79eIb.jpg