Cheaper GEBE pulley supply

[grinningremlin]

ok grinningremlin, i'm going to put you on the spot now. any details on how you were able to tap the 5/16-24 thread dead center down that bore? did you hand tap or use a drill? i've located a 5M14X9 and a 5M15X9 HTD timing pulley, also from Ametric, and need some guidance since they weren't that cheap and i don't want to muck them up. worst comes to worst i'll take it to a machine shop but prefer to do it on my own because i plan on experimenting with different gears/engines. i was not able to find anyone that has used a #15 gear for the GEBE and was wondering if it was even advisable. my plan is to mount my Mitsubishi TLE-43 or Tanaka PF-4000 with the #15 gear. comments anyone?

It wasn't easy.First had to grind flats so the vise would hold it.Then I started with some fine diamond coated dremel bits, worked up to some larger rougher diamond bits, finishing off with a regular metal bit, (all on a drill press) and opened it up enough for a hand tap.The hand tapping was my first attempt at anything this hard, and I could see the bit twist a little, but I got it through, finished with a little steel wool and the bit, it's ugly but it works.
It would be FAR easier to have a shop do the final tapping, or invest in a good bit set meant for this type boring.To sum up, it took a long time, a lot of work, and I can see why they're $32,.... but I'm still glad I can do it if needed.

 

[butterbean]

GG, question. What diameter are the gebe sheaves? I need a pulley that closely matches my current ratio. The output gear and the final gear (excluding the clutch and input gear) come to 4.8:1, with the final drive being 12.44:1. Knowing the diameter of the gebe sheave will tell me what size pulley I need for the output gear to match the 4.8:1 (or closely match) of my current setup. I'm going to do a two-speed manual by controlling the belt tension with a spring-loaded tensioner and a clutch lever (locked position gives one tension while engaged position gives another, one will be hill climbing gear and the other will be cruising).

 

[cpuaid]

approx. 16" across from one side to the other. the way i measured was from the bottom of the sheave channel where the belt seats

 

[cpuaid]

grinningremlin thanks for the info. i knew it didn't look as easy as it sounds. i bit the bullet and ordered the 5M14X9 gear, $18.20 shipped. so far i have called around 2 machine shops locally and no one wanted to do it. i may have to trial and error it on my own.

 

[butterbean]

Wonderful, now all I need is to know where to find a 3.5" v-belt pulley that can fit a 5/8 shaft.

 

[butterbean]

Maybe not so wonderful. Is the gebe sheave for a toothed belt or a v-belt? Might need a Whizzer sheave instead.

 

[grinningremlin]

Toothed belt, though I don't think it would matter much sheave-wise it would just slip a bit.Cpuaid, did you get it from Ametric? They state they can thread them, though they don't quote extra cost, and have yet to reply to my inquiry.

 

[grinningremlin]

Cpuaid, a couple tips:
Use an old GEBE belt wrapped onto the gear (pliers or vise-grips) so you can do the initial flat grind, or anytime you are in danger of marring teeth.I don't know if you're metal shop savvy, so not to be condescending:
Oil drip for boring/drilling/tapping just need a little
Take it slow
Tapping technique, tapering the opening after boring and before tapping, go until bind is felt, back off until you feel the ribbons "crack" then a few more in.Clean out often.
It's almost impossible to get the hole crooked if you work up in size incrementally.

Far left untapped, middle hand ground/tapped, right GEBE pulley.No need for polishing, the system does it on the road.

 

[butterbean]

What I need is a clutch bell for a belt-drive. I can swap out my existing clutch bell for one with a belt pulley and put a 9 tooth gear on my crankshaft and a 22 tooth input gear, then swap my output gear for my belt-driven clutch. This should work perfectly and be very close to my current ratio.

 

[butterbean]

Got it almost all figured out, just one last question. Can I file down the teeth on the gebe sheave to use a v-belt? I found a belt pulley clutch for 5/8 shaft and with a gebe sheave my cruising ratio would be 12:1 exactly, which is fine.