Gilmer versus Poly drive, opinions please

wiredone · Post by **wiredone** » Tue Feb 28, 2012 11:31 am

I defer to the sages on this one.
I am in the process of building my ultimate Mark 5, combining favorite features of a greenie with a 1983 standard Mark 5, and a 510 table upgrade.
I had already purchased and installed a 2 bearing quill from Simon Eng as I didn't like all the run-out in my single bearing quill. The factory 2 bearing quill is better, but not the be all to end all as far as quality is concerned.
The other day I was talking to Skip Campbell and we were discussing the slippage problem I was having in the poly belt on my unit. I mentioned how tight I had to make it in order to make it not slip etc, so I asked about a gilmer drive. It seems that a gilmer drive, coupled with a good operational clutch assembly, (which I will verify still works) would be actually better than a poly belt drive. I would gladly convert my gilmer quill to a two bearing if this is so.
(I noticed the slipping when I was using the 83 to polish way tubes)
Any cohesive thoughts on this idea?
Opinions?

JPG · Post by **JPG** » Tue Feb 28, 2012 11:45 am

wiredone wrote:I defer to the sages on this one.
I am in the process of building my ultimate Mark 5, combining favorite features of a greenie with a 1983 standard Mark 5, and a 510 table upgrade.
I had already purchased and installed a 2 bearing quill from Simon Eng as I didn't like all the run-out in my single bearing quill. The factory 2 bearing quill is better, but not the be all to end all as far as quality is concerned.
The other day I was talking to Skip Campbell and we were discussing the slippage problem I was having in the poly belt on my unit. I mentioned how tight I had to make it in order to make it not slip etc, so I asked about a gilmer drive. It seems that a gilmer drive, coupled with a good operational clutch assembly, (which I will verify still works) would be actually better than a poly belt drive. I would gladly convert my gilmer quill to a two bearing if this is so.
(I noticed the slipping when I was using the 83 to polish way tubes)
Any cohesive thoughts on this idea?
Opinions?

I have 'worn out' only one poly-v belt since 1963. Slipping did become an issue, but a new one has yet to slip. I think Bill Mayo's belt dressing recommendation is valid.

IIWM, I would stick with the poly-v.

reible · Post by **reible** » Tue Feb 28, 2012 11:49 am

Hi,

It sounds like you simply have a bad belt. Replace it and adjust as specified and away you go. Belts do wear out and having one slipping and being over tightened only makes things worse.

Ed

jmchale · Post by **jmchale** » Tue Feb 28, 2012 4:30 pm

I am certainly no sage, but I do have a gilmer belt.

I would not think that the problem I'm having right now (wearing of the side of the belt on the headstock housing) is an issue for a V-belt.
it is annoying and apparently I have to do some modifications to get this to stop happening.

SDSSmith · Post by **SDSSmith** » Tue Feb 28, 2012 6:52 pm

jmchale wrote:I am certainly no sage, but I do have a gilmer belt.

I would not think that the problem I'm having right now (wearing of the side of the belt on the headstock housing) is an issue for a V-belt.
it is annoying and apparently I have to do some modifications to get this to stop happening.

It can also occur with the poly v belt if it is not installed correctly.

billmayo · Post by **billmayo** » Tue Feb 28, 2012 11:58 pm

My first Shopsmith was a 1954 Gilmer Drive which I used for over 30 years with very little maintenance. I have stayed with the Gilmer Drive headstocks for all my additional personal Shopsmiths. Of course, my main reason was I could sell the Poly_V drive headstocks for more money and the Gilmer with a working clutch never has given me any problems. Same for using the 3/4 HP motor as I have a separate table saw where any extra power might be needed.

wiredone · Post by **wiredone** » Fri Mar 02, 2012 1:31 pm

So now, I'm switching gears. Again. I am looking into replacing the Poly belt and just running it. Of course, being my fathers son, I am a very frugal do it yourself kinda guy.
That being said, does anyone know the length of the poly belt or even a cross reference to a Gates or Dayco belt number?
I see the ones that are being sold by "tri state automotive" on ebay for just a couple of bucks less than SS does, and I would rather find the actual generic belt and save a few bucks.
By the way, the number printed on the Tri State Belt online is their phone number! How clever.
Also, they claim that SS motor belts are inferior and don't fit right, but theirs are the correct size and they have them custom made. Hmmm.............
Anyone add to this? Expand? I know that there was a thread last year about belts, but I have been searching on the forum and cannot find it.
Thanks.

trainguytom · Post by **trainguytom** » Fri Mar 02, 2012 2:06 pm

I've used both drive systems & see no problems with the gilmer system if working properly. (I actually think the the Gilmer machines were built in an era when they paid way more attention to quality & tolerances. I think even those old single bearing quills, if the machine has had proper maintenance, don't need upgrading. My old Goldie actually runs smoother & quieter & appears to have as much power as my 510.
That said, I do keep good belts on all machines & use belt dressing, and never had a slippage issue on a poly-v.

wiredone · Post by **wiredone** » Fri Mar 02, 2012 2:39 pm

trainguytom wrote:I've used both drive systems & see no problems with the gilmer system if working properly. (I actually think the the Gilmer machines were built in an era when they paid way more attention to quality & tolerances. I think even those old single bearing quills, if the machine has had proper maintenance, don't need upgrading. My old Goldie actually runs smoother & quieter & appears to have as much power as my 510.
That said, I do keep good belts on all machines & use belt dressing, and never had a slippage issue on a poly-v.

I realized the other day that I no longer have the Gilmer quill. Sold it without thinking. I too really like the old school way of doing things. I tend to think that the reason they changed to poly vee belt was to save production costs, not for "improvement". This way they could eliminate the expensive clutch mechanism and still retain the slippage feature.
I'm going to look at a very tired goldie as a parts unit this weekend, I've seen it before, it's lived outside a long long time and is a donor.
Maybe it will be an early one with a Gilmer quill. we'll see.

robinson46176 · Post by **robinson46176** » Fri Mar 02, 2012 3:42 pm

Many folks do not have a clear understanding of just how Vee belts really work. They are not just a V shape that fits in a V shape pulley. Even some sites that describe how they work leave out the "bulge" factor. Being forced around a pulley causes them to bulge on the sides and grip more. Poly Vee's are no exception. Many times if you examine a worn Vee belt you will see that the sides have become slightly concave. When that happens the belt has less grip. Poly Vee's can look good but no longer have enough material to "bulge" when wrapped around the pulley.
Here is a link to an old article that describes the bulge factor. Very long link, hope it works OK.
http://books.google.com/books?id=qSEDAAAAMBAJ&pg=RA2-PA228&lpg=RA2-PA228&dq=how+a+vee+belt+bulge&source=bl&ots=Ih5Xc0-gsF&sig=SmWQutScenN8dfeMwTqfb6g59X8&hl=en&sa=X&ei=ZSxRT7elOsnW0QHSgamCDg&sqi=2&ved=0CGEQ6AEwAw#v=onepage&q=how%20a%20vee%20belt%20bulge&f=false

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Gilmer versus Poly drive, opinions please

Gilmer versus Poly drive, opinions please

Have used both