J-series microbelt profile for machining pulleys

Continental have a good design guide here

. You should find the details you need such as spacing, V angle etc in the first 12 pages or so.

Thanks, I saved that as a German-English technical dictionary. The translation is almost literally word for word and yet flows decently in English.

--jsw

There is a purely English version of that document available but that was the first version I could find with a quick search.

David Billington fired this volley in news:nmick5$f0g$1 @dont-email.me:

Despite the fact that his customer is Amish, I seriously doubt if the document need be in German!

However, since he was asking, and you were answering, mightn't it have been nice if you'd published the link to what you found?

Lloyd

See my first reply to the OP where I posted the link to the document. It's in German and English.

An English version

*

*

I subscribe to the German-language version of this and have trouble with the numerous technical terms that aren't in my dictionary.

--jsw

ave their own - and very inconvenient at times!

Awesome, thank you. I got the groove angle right, 40 deg. but the spacing i s 2.34 mm, a little off from my 2.38 mm, the decimal equivalent of 3/32". A nd 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 proble ms. The client is happy with it so guess I am too. Here's a couple shots of what he's doing:

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.

Looking at the specifications for the J at +-0.03mm deviation from the pitch as you say you're +0.01mm over but that tolerance means that 2 grooves could be 0.06mm off nominal and still be OK. The sum of deviations is given as +-0.3mm so if you're not using many ribs you may be fine as you're at 2.38mm, especially if you're not using many ribs and not loading it near the limit.

have their own - and very inconvenient at times!

ng 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 erro r. 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 pr oblems. The client is happy with it so guess I am too.

I should get me one of dem DRO thingies. The lead screw method was a pain i n 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 c an be used somewhere else. Here's my semi-crude indexing setup on my Emco M aier Compact 8:

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.