up grading my vintage Unisaw motor

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Forum topic by castlebed posted 06-01-2014 08:03 PM 1947 views 0 times favorited 8 replies Add to Favorites Watch
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4 posts in 1726 days

06-01-2014 08:03 PM

Topic tags/keywords: unisaw motor upgrade tablesaw

I need some assistance in replacing the motor in my 1944 Unisaw I plan on buying a LEESON 1.5hp replacement motor but I cannot find info. on what size pulley I need to run it I was told I have to get a different one then the 5.25 that is currently on the RI bullet motor

-- Mitch

8 replies so far

View AnonymousRequest's profile


861 posts in 1819 days

#1 posted 06-01-2014 09:55 PM

Go to Ask there and you’ll have your answer within minutes.

View ToddJB's profile


8331 posts in 2401 days

#2 posted 06-01-2014 10:23 PM

Unisaw made two pulley sizes. One for the 3500rpm and one for the 1740. The bigger one would be for the 1740. If the new lesson is 1740, you need the same pulley size, but check the motor shaft diameter. If it is 3500 you’ll need 3.5”.

May I ask why the “upgrade”?

-- I came - I sawed - I over-built

View August McCormick Lehman III's profile

August McCormick Lehman III

1810 posts in 1761 days

#3 posted 06-01-2014 10:27 PM

If you don’t mind my 2 cents
Buy a TEFC motor
Best of luck.


View castlebed's profile


4 posts in 1726 days

#4 posted 06-02-2014 12:19 AM

Thank you for the knowledge just would like to keep the Original motor healthy seems to be slowing a little

-- Mitch

View bigblockyeti's profile


5415 posts in 1991 days

#5 posted 06-02-2014 12:58 AM

+1 to the TEFC motor, if your current RI motor is starting to slow, dust accumulation on and in the commutator could be part of the problem. An enclosed motor would help prevent this from happening again. In all likelihood the replacement spins at roughly twice the speed of the old motor necessitating a pulley of half the diameter, and shorter belts as well. The folks at would probably be able to tell you not only the pulley you need, but the correct belt size also without having to measure anything on your own.

-- "Lack of effort will result in failure with amazing predictability" - Me

View castlebed's profile


4 posts in 1726 days

#6 posted 11-29-2014 08:14 AM

Thank you everyone who replied to my question ToddJB thanks I purchased a 2hp TEFC 3450 rpm motor would that still use the 3.5”pulley? thanks August McCormick Lehman III I did buy a TEFC motor should have it in a couple days and last but not least thanks bigblockyeti I am a member of I will check with them thanks everyone

-- Mitch

View Minorhero's profile


373 posts in 2875 days

#7 posted 11-29-2014 12:12 PM

Probably a bit late, but be aware your new motor will not fit an un altered saw cabinet and allow 45 degree angle cuts at all extensions. The original motors are prized for that reason.

View castlebed's profile


4 posts in 1726 days

#8 posted 11-29-2014 07:10 PM

Thanks Minorhero The cabinet to my unisaw was already manipulated for an aftermarket motor universal mounting brackets were fabricated at the Douglas aircraft facility were the saw was originally used

-- Mitch

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