Drive Belt slipping?

mike2810 · Post by **mike2810** » Mon Oct 13, 2008 4:11 pm

I finally had to replace the drive belt (part 113) on my model 510. It was not that much of a problem and thought the process went well. After the install, I turned the 510 on and ran it up and down the speeds. Every thing seemed to work well. The last two times I went to use the 510, it starts up just fine. When I go to increase the speed (saw), the drivebelt sometimes slips, and no increase in speed occurs or the blade slows down. If I increase the speed very slowly (1/4 turn 15 seconds or so), the problem does not occur.

I checked the movement of the speed changer and it seems to work ok. What I noticed (with the cover off) is as the pulleys squeeze together the belt seems to move up in the slot and slips. I am not sure if belt dressing would help, I have a bad speed changer or pulley.

Any ideas would be appreciated.

beeg · Post by **beeg** » Mon Oct 13, 2008 4:38 pm

Have you cleaned and lubed lately? Did you follow the replacement instructions, they sent?

dusty · Post by **dusty** » Mon Oct 13, 2008 5:18 pm

mike2810 wrote:I finally had to replace the drive belt (part 113) on my model 510. It was not that much of a problem and thought the process went well. After the install, I turned the 510 on and ran it up and down the speeds. Every thing seemed to work well. The last two times I went to use the 510, it starts up just fine. When I go to increase the speed (saw), the drivebelt sometimes slips, and no increase in speed occurs or the blade slows down. If I increase the speed very slowly (1/4 turn 15 seconds or so), the problem does not occur.

I checked the movement of the speed changer and it seems to work ok. What I noticed (with the cover off) is as the pulleys squeeze together the belt seems to move up in the slot and slips. I am not sure if belt dressing would help, I have a bad speed changer or pulley.

Any ideas would be appreciated.

There has been some past discussion about the quality of a replacement drive belt. The issue was that the belt seemed to cause some unwanted vibration. Is it also possible that it also attributes to slippage.

billmayo · Post by **billmayo** » Mon Oct 13, 2008 5:28 pm

A very common problem that I find. The new belt forces the floating sheave on the motor to open wider where there is crud (Nick's word) that now gets inside the floating sheave. The floating sheave is just sticking a little but will get worse if not attended to. What I used to do was set the speed to about 2/3 of the way. With the belt cover slide back out of the way, I put a few drops of oil in the floating sheave oil hole and on the motor shaft key that is under the spring. I grip the floating sheave (careful of your fingers) and pull it to me a little and let go. The motor belt is still on. Do not let go if there is no motor belt to absolve the shock of the sheaves closing. I put more oil on the motor shaft key (flushing the crud) and pull a little further. Repeat until you can pull the floating sheave all the way toward the end (spring will be fully compressed).

Now I set the speed control to fast, then I spray an oil cutting cleaner/degreaser on the motor shaft and use a stiff brush to clean the crud off the motor shaft and key before doing anything. Then lubicate the floating sheave and the key on the shaft and test for sticking.

If it still sticks when you do this, then I remove the motor. Then remove the washer, snap ring and spring. The clean the motor shaft, key and inside the floating sheave with a good cleaner/degreaser. Oil the shaft and key. Make sure the floating sheave slides freely on the motor shaft and key. If the motor is removed, be sure to check the fan sheave set screw as I have found a few of them that had loosen. There are available instructions on-line for removing the motor and the sheave spring.

mike2810 wrote:I finally had to replace the drive belt (part 113) on my model 510. It was not that much of a problem and thought the process went well. After the install, I turned the 510 on and ran it up and down the speeds. Every thing seemed to work well. The last two times I went to use the 510, it starts up just fine. When I go to increase the speed (saw), the drivebelt sometimes slips, and no increase in speed occurs or the blade slows down. If I increase the speed very slowly (1/4 turn 15 seconds or so), the problem does not occur.

I checked the movement of the speed changer and it seems to work ok. What I noticed (with the cover off) is as the pulleys squeeze together the belt seems to move up in the slot and slips. I am not sure if belt dressing would help, I have a bad speed changer or pulley.

Any ideas would be appreciated.

charlese · Post by **charlese** » Mon Oct 13, 2008 6:30 pm

Thanks for the explanation, Bill! It sure leads to more understanding of what goes on here!

I'd like to add - - Using what I think is an added precaution to prevent crud from forming between the floating sheave and the motor shaft, After putting a drop into the small hole beneath the spring , I always put a few drops of oil on the outside of the floating sheave's tube on the motor shaft then manually pull (slide) the sheave several times all the way to compress the spring. This seems to keep the sheave really free and easy to move. The only caution I have here is to wipe any excess oil off of the spring to prevent an oil spray on the bench tubes and underside of the way tubes. Additionally it is always a good practice to clean all tubes with mineral spirits and re-wax.

BTW - After slicing the bumps from my new Gates drive belt, I've logged 35 hours on it. It is still running smoothly

and the width measures the same as when new. I did not follow directions to adjust high speed so the belt is 1/4" below the lower sheaves. I just kept the same 1/8" setting. More on this later - after more hours.

billmayo · Post by **billmayo** » Mon Oct 13, 2008 7:40 pm

Thanks charlese. Excellant idea on how to clean and prevent crud on the motor shaft. Most headstocks I repair have had little or no lubication.

mike2810 · Post by **mike2810** » Tue Oct 14, 2008 12:16 am

Thanks everyone for the tips. I did follow the instructions sent by Shopsmith. I also keep to a good maintenance schedule including lubrication and blowing out sawdust debri. I'll try the recommendations and see if it cures the problem.

Problem solved: Went in and cleaned what little sawdust was present, lubricated both top and bottom. It solved the issue.
Thanks again.

allsas · Post by **allsas** » Sat Mar 14, 2009 2:35 am

I used this forum topic to correct a drive belt that started to slip and vibrate after oiling. The control sheave responded to the oiling but the headstock began to vibrate during the speed runup/rundown. More oil to the fan sheave did not loosen the fan sheave so that it could be moved manually as suggested by Chuck in post #5.

I tried more oil and a spray of WD 40 to clean the sheave and shaft plus let it soak overnight. In the morning, it was still unmoveable, necessitating removing the headstock from the way tubes, the motor pan from the headstock, and the pan from the motor.

I was really worried about getting about getting this pulley of the shaft without a hydralic press. The removal of the spring let me search the area for the washer. I found it in the grass beyond the garage apron. I elected to support the pulley on two 3/4" pieces of stock over cinder blocks. To make sure that the stock was close to the shaft, I tapped the stock towards the shaft. To my surprise the pieces of stock acted as a wedge and moved the pulley towards the end of the motor shaft. A drive pin and 3# ball pien hammer, applied cautiously, moved the pulley beyond the end of the motor shaft, and off the shaft.

I found a quantity of oil soaked wood dust in the pulley and around the shaft. The process of pounding the pulley off produced a bunch of fine dust from inside the motor. I had used compressed air to blow dust out of the motor before starting the oiling. I thought it was all out of there. More compressed air produced a LOT of dust from both ends of the motor.

The cleaned, oiled pulley slipped on the shaft easily. The neighbor was drafted to to put the retaining ring on the shaft as I forced the spring and washer in place.

No shade trees or cinder blocks were harmed during this attempt to fix the Mark V.

The suggestions from Chuck and Bill Mayo were Extremely useful. The Search for Fan Sheave Sticking produced only this thread. Bill must be the doctor at the Mayo Clinic for Mark V's. I found his post on analyzing Quills extremely helpful. Thanks Chuck and Bill.

a1gutterman · Post by **a1gutterman** » Sat Mar 14, 2009 11:48 am

allsas wrote:... The removal of the spring let me search the area for the washer. I found it in the grass beyond the garage apron...

Glad you got that extra excercise in! Really glad that you diagnosed and fixed the problem. May this forum site be with us a long time.

JPG · Post by **JPG** » Sat Mar 14, 2009 12:33 pm

a1gutterman wrote: Glad you got that extra excercise in! Really glad that you diagnosed and fixed the problem. May this forum site be with us a long time.

Glad that exercise did NOT involve a walk to the Emergency room!:eek:

Beware of compressed springs!!!!:o

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