Just turned on my 1982 Mark V 500 for first time. I acquired from a friend and rebuilt headstock. I have 4 belts to try, Jacob A belt, SS new, Kevlar belt and a 32 link belt form HF. Link belt is on now. I have a calibrated RPM gauge and the slowest speed I get is 1080 rpm. The motor is running at 3580 rpm. My questions are:
What is the motor rpm supposed to be and will a longer or shorter belt slow it down?
I can't go any slower or the belt hits the casting.
Sorry about the pics, for some reason they rotated when I inserted.
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1982 Mark V 500 w/2 bandsaws(cast iron and aluminum table), power station, belt sander, jointer, jigsaw and lathe duplicator.
Low RPM should be in the 700 range. Your speed is most likely a result of having the wrong belt length.
My suggestion would be to put on the Shopsmith branded V belt and try again.
Bill V
Motor RPM is 3450. IIRC that is at 100% rated power/load. Theoretical no load speed is 3600, never reached in practice. So the useful range is from 3450 to a bit less than 3600 from full load to no load. You are in a low load condition, so your motor speed seems reasonable to me.
A longer than nominal belt will cause the machine to run at higher RPM by allowing the motor sheaves to move closer together. You might try removing a link, but I have no experience with link belts in headstocks. Your closest to nominal speed results will probably occur with the new SS belt. (IIRC the Jacob belt is metric and slightly longer and wider than nominal. The others are unknowns to me.)
Both the width and length of the belt effect the speed, Also, the tabs on the link belt make it deeper through and will limit how far the belt can go in the sheaves.
Ron Dyck
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10ER #23430, 10ER #84609, 10ER #94987,two SS A-34 jigsaws for 10ER.
1959 Mark 5 #356595 Greenie, SS Magna Jointer, SS planer, SS bandsaw, SS scroll saw (gray), DC3300,
A longer belt will cause higher speeds since the floating(motor) sheave must compress(close) more to maintain tension and that results in the belt riding further out on the motor pulley.
A shorter belt will invert that. The belt will ride further IN on the motor pulley causing slower speed range.
The control sheave range is fairly consistent with a properly set high speed stop.
A narrower belt will cause faster speeds since it will be riding further INTO the idler pulley and further OUT on the motor pulley.(wear can create that)
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
The 32 link belt started same size as SS and is a little wider. But after running for a few minutes, it stretched so I removed 2 links to make it same size as SS. Since it is a little wider, it hits the casting when trying to get below 760 rpm. I went back to the SS belt.
1982 Mark V 500 w/2 bandsaws(cast iron and aluminum table), power station, belt sander, jointer, jigsaw and lathe duplicator.
Gio800 wrote: ↑Mon Feb 01, 2021 8:33 am
The 32 link belt started same size as SS and is a little wider. But after running for a few minutes, it stretched so I removed 2 links to make it same size as SS. Since it is a little wider, it hits the casting when trying to get below 760 rpm. I went back to the SS belt.
Check out what 29 links will give you.(is odd link count possible?)
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
Ok, I'll bite on this one. What are the advantages of using a link belt on a Mark V? As I understand it, the marketing for link belts promote lower vibration from their use. However, I have seen woodworking discussions on them on other forums and the conclusion often is that they only offer a benefit when the motor mount is a gravity type design. Vibration is much lower for a link belt, e.g. when used on a table saw where the motor weight holds belt tension due to gravity. When the motor is a fixed mount it is my understanding that they offer no less vibration than the equivalent V belt. The Mark V would be this latter case and presumably has no less vibration with a link belt. Disadvantages are that links do break, but repairs are easy. Also, they can be noisier than an equivalent V belt. Of course when a V belt replacement isn't handy, etc. I get that link belts offer an advantage. Just surprised to see discussion of link belts from time to time on this forum. IMHO I don't see much benefit to using them on a Mark V. Comments?
RF Guy