Page 1 of 2
Gilmer belt alignment
Posted: Wed Oct 20, 2021 6:54 pm
by HopefulSSer
I've installed the new gilmer belt in my headstock, however I'm a little concerned about the alignment. It's riding up against the shoulder on the outboard end of the cog. The old one did the same before it broke.
Should it be more centered? And assuming yes, how would one adjust it? I don't see any provision for that. The idler bush seems like it should abut the stop screw, and the idler bearing has a groove to accept the point of the grub screw, so everything seems to have a fixed position. And if I were to move the idler position, it would affect the v-belt alignment. What am I missing here?
Thanks!
- belt.jpg (32.71 KiB) Viewed 2393 times
Re: Gilmer belt alignment
Posted: Wed Oct 20, 2021 8:35 pm
by JPG
Post a pix that includes both ends of the belt(drive sleeve etc., and idler sheave, and end of idler shaft etc..
It does tend to track there!
Re: Gilmer belt alignment
Posted: Thu Oct 21, 2021 11:27 am
by HopefulSSer
Re: Gilmer belt alignment
Posted: Thu Oct 21, 2021 11:55 am
by DLB
HopefulSSer wrote: ↑Thu Oct 21, 2021 11:27 am
It seems like the idler shaft and drive sleeve axes are not parallel. The idler seems like it's "tipped up" slightly on the sheave end, making the outboard side of the belt a little tighter than the inboard. Maybe the pictures will show what I'm talking about. I was able to get a little breathing room on the drive sleeve cog by scootching the bearing inward in the offset bush but I don't like it.
First, full disclosure, my Gilmer machine appears to be worse than yours. I haven't done much with it in recent years, and it's pretty rough. The belt always rode where yours started.
As part of a PowerPro rabbit hole, I found I could measure the angles of the shafts by putting a lathe faceplate on them and measuring the relative angles of them. With any luck at all, the face plate will be extremely close to normal to the shaft. I used two 3-3/4" face plates but I think the larger one would work as well. I used a Wixie to measure the angle, there are many alternatives. There are some pretty good smart phone apps, though they can't publish accuracy. (I don't like to use my phone for things like this out in the shop due to potential for dropping it. Wixie or competitors are relatively cheap and durable.)
It's important to make sure you are using a Gilmer belt tension procedure. IIRC it will should have somewhat less tension compared to a Poly-V.
- David
Re: Gilmer belt alignment
Posted: Thu Oct 21, 2021 12:02 pm
by edma194
Gilmer belts can slide side to side along the cogwheel unlike the multi-groove belts. If it's not wearing out the side of the belt from contact then you should leave it alone until you can identify an actual problem in operation.
Re: Gilmer belt alignment
Posted: Thu Oct 21, 2021 12:11 pm
by HopefulSSer
DLB wrote: ↑Thu Oct 21, 2021 11:55 am
First, full disclosure, my Gilmer machine appears to be worse than yours. I haven't done much with it in recent years, and it's pretty rough. The belt always rode where yours started.
As part of a PowerPro rabbit hole, I found I could measure the angles of the shafts by putting a lathe faceplate on them and measuring the relative angles of them. With any luck at all, the face plate will be extremely close to normal to the shaft. I used two 3-3/4" face plates but I think the larger one would work as well. I used a Wixie to measure the angle, there are many alternatives. There are some pretty good smart phone apps, though they can't publish accuracy. (I don't like to use my phone for things like this out in the shop due to potential for dropping it. Wixie or competitors are relatively cheap and durable.)
It's important to make sure you are using a Gilmer belt tension procedure. IIRC it will should have somewhat less tension compared to a Poly-V.
- David
Not familiar with Wixie. I'll have to look that up....
RE tensioning -- the belt (directly from SS) came with instructions, and there's an admonition on the website to call tech service when installing for proper tensioning procedure. I called and they read to me the sheet that came with the belt.
They said set the speed to G or H, tighten the belt til it gets noisy, then back off until it's quiet again.
Thanks for the info!
Re: Gilmer belt alignment
Posted: Thu Oct 21, 2021 12:13 pm
by HopefulSSer
edma194 wrote: ↑Thu Oct 21, 2021 12:02 pm
Gilmer belts can slide side to side along the cogwheel unlike the multi-groove belts. If it's not wearing out the side of the belt from contact then you should leave it alone until you can identify an actual problem in operation.
I've not run it enough of course to know if it would be a problem, it just looked wrong. Since I'm new to these machines I figured I should investigate before I break something.
I'll run it a while and keep an eye on it. It might be fine!
Thanks!
Re: Gilmer belt alignment
Posted: Thu Oct 21, 2021 2:33 pm
by JPG
I'se a bit confused. The third pix above shows a poly-v idler pulley??? BTW it is one groove too far towards the back(s/b two vacant grooves on both sides)(pulley has 13 grooves - belt has 9 ribs.
Second pix-The eccentric is NOT fully inserted(washer should be flat against it)(would do the same as you did with the bearing).
I assume you moved the bearing away from the set screw positioning??
Re: Gilmer belt alignment
Posted: Thu Oct 21, 2021 2:43 pm
by DLB
JPG wrote: ↑Thu Oct 21, 2021 2:33 pm
I'se a bit confused. The third pix above shows a poly-v idler pulley??? BTW it is one groove too far towards the back(s/b two vacant grooves on both sides)(pulley has 13 grooves - belt has 9 ribs.
I'm not seeing that.
Could you be seeing the compressed spring and cap on the motor shaft in the background? Or, please circle for those of us (most of us, I think) less observant...
- David
Re: Gilmer belt alignment
Posted: Thu Oct 21, 2021 3:08 pm
by JPG
I think "THEE" are more observant than I. Yes I was referring to the motor shaft spring.
