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POWERMATIC 50 JOINTER HELP

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Forum topic by kooldecker posted 02-24-2015 02:40 PM 737 views 0 times favorited 7 replies Add to Favorites Watch
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kooldecker

59 posts in 1033 days


02-24-2015 02:40 PM

Hey there,
I purchased a sweet pm50 about a year ago, one of the older pea green ones. its only now im getting around to looking at it in the light and actually touching it lol. I am going over it and making a new base, it came with a homemade one that is just not my cup o tea so to speak. it came with an undersized homecraft motor, that I am changing out. I have a 1hp 3450 or so motor from an old craftsman table saw that’s in really good shape and should be just the ticket, HOWEVER the pulley on the homecraft is NOT the Powermatic pulley that the jointer came with. Im wondering if anybody out there that has a PM50 could do me a really big favor and measure their pulleys for me and give me a measurement to at least get me in the ballpark. I of all people know how busy everybody is, and I cant tell you how much I would appreciate this favor! its mainly the pulley on the motor, the top one is original I belive, matching paint in groove, but I just want to get the bottom one close. according to the owners manuals they came with 3600 rpm motors. so if im around 3450 and its close, I have some wiggle room without going over the recommended 5000 rpms. again I would appreciate any help or light you guys could shed on the matter. thanks again and I wish you safe shavings!
Jason AKA kooldecker

-- " I dont understand......I cut that board AT LEAST 4 times and its STILL too short!"


7 replies so far

View waho6o9's profile

waho6o9

7174 posts in 2041 days


#1 posted 02-24-2015 06:40 PM

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MrUnix

4226 posts in 1663 days


#2 posted 02-24-2015 07:03 PM

Powermatic says NOT to use anything bigger than 3/4 HP and a 1/2 HP motor is standard and should be fine (as stated in the maintenance and parts manual). It also recommends a max of 5000 RPM at the cutter head, so just size your pulleys appropriately for the correct speed (depending on what you have at the cutter head and/or motor, whichever one you want to change if at all).

Cheers,
Brad

PS: The parts diagram also lists the pulley sizes used on the stock setup.. an AK-25 (2.5”) and AK-34 (3.45”)

-- Brad in FL - To be old and wise, you must first be young and stupid

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runswithscissors

2189 posts in 1489 days


#3 posted 02-24-2015 08:38 PM

Just curious: can anyone explain to me why too much horsepower is “too much”?

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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MrUnix

4226 posts in 1663 days


#4 posted 02-24-2015 08:54 PM


Just curious: can anyone explain to me why too much horsepower is “too much”?

Because of the way the machine was designed and the forces it was designed to be able to handle safely. Parts can only take so much stress before bad things happen.

Cheers,
Brad

PS: there is probably a good reason for the big WARNING on the first page of the manual for that jointer regarding motor size and max rpm.. while 1HP might work just fine, I tend to follow the manufacturers recomendations since they were the ones who designed it and know best what it was designed to handle.

-- Brad in FL - To be old and wise, you must first be young and stupid

View Minorhero's profile

Minorhero

372 posts in 2069 days


#5 posted 02-24-2015 08:55 PM

It probably does not matter regarding hp of the motor. For pulley size you can use a size calculator. http://www.blocklayer.com/pulley-belteng.aspx

Good luck.

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kooldecker

59 posts in 1033 days


#6 posted 02-24-2015 09:59 PM

I was not really sweating the HP. I figured that as long as I had the rpms below 5000 I was going to be safe. MrUnix thank you for clarifying the pulley numbers for me. I just thought those were part numbers and didn’t think they corresponded in any way to the size. I had poured over all the parts lists I could find, as there are like 3-4 of them over the years, but kept coming up with those darn part numbers lol. my ignorance shines once again. anyway it looks like the top pulley isn’t stock either then. I measured 1 3/8. so I will try minors calculator. thank you again guys for your help. and if anyody has any more to add about the max horsepower issue, could you elaborate ? thanks again for all the help!!
safe shavings!

-- " I dont understand......I cut that board AT LEAST 4 times and its STILL too short!"

View greenacres2's profile

greenacres2

251 posts in 1632 days


#7 posted 02-25-2015 03:00 AM



Powermatic says NOT to use anything bigger than 3/4 HP and a 1/2 HP motor is standard and should be fine (as stated in the maintenance and parts manual). It also recommends a max of 5000 RPM at the cutter head, so just size your pulleys appropriately for the correct speed (depending on what you have at the cutter head and/or motor, whichever one you want to change if at all).

Cheers,
Brad

PS: The parts diagram also lists the pulley sizes used on the stock setup.. an AK-25 (2.5”) and AK-34 (3.45”)

- MrUnix

Makes perfect mathematical sense. 3.45 / 2.5 = 1.38 ratio. 3600 rpm motor * 1.38 = 4,968 rpm at the cutterhead.

earl

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