Mark V Speed Control

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BigSky
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Mark V Speed Control

Post by BigSky »

Help me please.

I am working on a Mark V after having it totally disassembled.

It was in terrible condition due to negligence of a previous owner.

My problem is with the pulley settings.

IIUC when the pulley rotation speed is equal to the motor speed (3450) the pulleys should equal in size and rotating at the same speed.

If I get that condition to exist - at what speed should the saw blade be rotating.

How deep into the pullets should the belt be riding.
edma194
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Re: Mark V Speed Control

Post by edma194 »

With the pulleys at the same diameter they and the idler shaft will be running at motor speed. However, the main spindle does not run at the same speed as the idler shaft. There is 1.6:1 ratio between idler shaft speed and main spindle speed. So the blade should be running somewhere around 2160RPM. Remember that the speed of the motor will not be 3450RPM, it typically is something under that, somewhere between 3000 and 3450RPM depending on load conditions.
Ed from Rhode Island

510 PowerPro Double Tilt:Greenie PowerPro Drill Press:500 Sanding Shorty w/Belt&Strip Sanders
Super Sawsmith 2000:Scroll Saw w/Stand:Joint-Matic:Power Station:Power Stand:Bandsaw:Joiner:Jigsaw
1961 Goldie:1960 Sawsmith RAS:10ER
BigSky
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Re: Mark V Speed Control

Post by BigSky »

That is good news. I knew there was a spindle difference but was not taking it into consideration.

Until I understand better, I will use only the pulley speeds for my calculations.

My confusion comes when I try to track the differences in pulley size. It seems that if one pulley gets 1/4" larger the other should get the same only smaller. That does not seem to be the case.
DLB
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Re: Mark V Speed Control

Post by DLB »

edma194 wrote: Wed Jul 13, 2022 2:40 pm With the pulleys at the same diameter they and the idler shaft will be running at motor speed. However, the main spindle does not run at the same speed as the idler shaft. There is 1.6:1 ratio between idler shaft speed and main spindle speed. So the blade should be running somewhere around 2160RPM. Remember that the speed of the motor will not be 3450RPM, it typically is something under that, somewhere between 3000 and 3450RPM depending on load conditions.
I don't want to derail the conversation, but I think the motor will run between 3450 at max rated load and higher RPM at reduced load. Up to 3600 RPM theoretical, but never realized. This, in fact, is the great think about induction motors, they have excellent speed control independent of load without an external speed controller.

- David
edma194
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Re: Mark V Speed Control

Post by edma194 »

Yes, that makes sense. 6000RPM should be the no load speed based on the number of poles.
Ed from Rhode Island

510 PowerPro Double Tilt:Greenie PowerPro Drill Press:500 Sanding Shorty w/Belt&Strip Sanders
Super Sawsmith 2000:Scroll Saw w/Stand:Joint-Matic:Power Station:Power Stand:Bandsaw:Joiner:Jigsaw
1961 Goldie:1960 Sawsmith RAS:10ER
edma194
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Re: Mark V Speed Control

Post by edma194 »

BigSky wrote: Wed Jul 13, 2022 3:21 pm Until I understand better, I will use only the pulley speeds for my calculations.
What are you calculating?
Ed from Rhode Island

510 PowerPro Double Tilt:Greenie PowerPro Drill Press:500 Sanding Shorty w/Belt&Strip Sanders
Super Sawsmith 2000:Scroll Saw w/Stand:Joint-Matic:Power Station:Power Stand:Bandsaw:Joiner:Jigsaw
1961 Goldie:1960 Sawsmith RAS:10ER
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JPG
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Re: Mark V Speed Control

Post by JPG »

edma194 wrote: Wed Jul 13, 2022 5:31 pm Yes, that makes sense. 6000RPM should be the no load speed based on the number of poles.
3600 makes more sense!
╔═══╗
╟JPG ╢
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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'/ 10
E[/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
edma194
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Re: Mark V Speed Control

Post by edma194 »

Where did 6000 come from? Yes, 3600 does make sense. I got no idea how I ended up writing 6000.
Ed from Rhode Island

510 PowerPro Double Tilt:Greenie PowerPro Drill Press:500 Sanding Shorty w/Belt&Strip Sanders
Super Sawsmith 2000:Scroll Saw w/Stand:Joint-Matic:Power Station:Power Stand:Bandsaw:Joiner:Jigsaw
1961 Goldie:1960 Sawsmith RAS:10ER
BigSky
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Re: Mark V Speed Control

Post by BigSky »

Thanks for the input. Yes, I do believe that I have confirmed mathematically that the two pulley sets change in equal and opposite direction.
edma194
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Re: Mark V Speed Control

Post by edma194 »

BigSky wrote: Thu Jul 14, 2022 2:14 pm Thanks for the input. Yes, I do believe that I have confirmed mathematically that the two pulley sets change in equal and opposite direction.
There are some good drawings of the mechanism somewhere on the forum that show the range of movement of the split sheaves and some measurements. They move in concert like that because the lower sheave is moved by a spring that will equalize the diameters of the pulleys.
Ed from Rhode Island

510 PowerPro Double Tilt:Greenie PowerPro Drill Press:500 Sanding Shorty w/Belt&Strip Sanders
Super Sawsmith 2000:Scroll Saw w/Stand:Joint-Matic:Power Station:Power Stand:Bandsaw:Joiner:Jigsaw
1961 Goldie:1960 Sawsmith RAS:10ER
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