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Replacing 1hp Westinghouse 1750 rpm motor in old (1950s or 60s, i think) craftsman table saw.

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Forum topic by Sam posted 09-17-2017 10:49 PM 163 views 0 times favorited 2 replies Add to Favorites Watch
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Sam

16 posts in 708 days


09-17-2017 10:49 PM

Topic tags/keywords: table saw question vintage craftsman

Due to being severely financially challenged, I’m looking for a very inexpensive used table saw, like an older model that may need some repair/restoration that I could do myself.

I currently have an opportunity to buy an old Craftsman (100 series, I think) with the original Westinghouse motor (see photos). The seller doesn’t know anything about the saw (it belonged to a deceased relative) other than the fact that it runs. She also told me that her boyfriend said the “motor was weak”.

I’m wondering what a “weak” motor could mean. It’s 1hp, but it’s only 1750 rpm. Could the low Rpm be the reason for calling it “weak”?

From what I understand, most table saws are around 3450 rpm. Would I have problems with the original 1750rpm motor? If so, would it be difficult for me to replace it with a more powerful motor?

The seller has agreed to sell me the saw for only $35. I’d still be able to spend about another $125 to get the saw performing adequately (including a decent blade). If anyone can give me some advice about what I’d most likely need to do, I’d appreciate it.

I’m not new to woodworking, I’ve just never had a table saw (I know that’s weird). I started with hand tools 5 years ago, and that’s what I prefer for most tasks, but after a couple years, I decided I also wanted to use power tools for certain things. Over the past 2 years I’ve acquired a D.P., bandsaw, and thickness planer. Now I’m ready for a table saw, and I feel like this Craftsman could be a good choice for me. I’d truly appreciate some info/advice from those with more knowledge on the subject.

Thanks.

-- Sam, Pittsburgh PA


2 replies so far

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MrUnix

5803 posts in 1980 days


#1 posted 09-18-2017 12:08 AM

Not sure exactly what specific model that is, but the 1959 10” saw that looks very much like yours recommends a minimum 3/4hp 3450 rpm motor, with an arbor speed of 3450 rpm (ie: a 1:1 pulley ratio). A 1hp motor would be fine if it were the proper speed… with a 1725 rpm motor, you need a 1:2 pulley ratio to get the correct arbor speed – so see what is on there. I’d run it first and see how it performs before doing anything else… it obviously was being used as-is at some point, so it might just be fine for what you need. Otherwise, trying a different pulley ratio first would be cheaper than finding a motor. If that doesn’t work out, it should take a pretty standard mount motor (NEMA 56 frame) that you can source from lots of different places.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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Sam

16 posts in 708 days


#2 posted 09-18-2017 02:04 AM


minimum 3/4hp 3450 rpm motor, with an arbor speed of 3450 rpm (ie: a 1:1 pulley ratio). A 1hp motor would be fine if it were the proper speed… with a 1725 rpm motor, you need a 1:2 pulley ratio to get the correct arbor speed –

Brad, thanks for that info. I haven’t actually purchased this saw yet, but I’m supposed to pick it tomorrow evening… unless someone tells me something that would change my mind.

This is probably a dumb question, but when you say a 2:1 pulley ratio to get the proper speed, that means a smaller pulley on the saw, right? Or do I put a bigger pulley on the motor?

I think the pulleys are the same size right now, and since the motor says 1725 rpm, I guess that means the blade is turning at 1725 rpm (was there actually a time table saws were made to run at 1725 rpm?) Also, from what I understand, the motor is mounted in such a way that it permits movement, because the motor moves slightly when the blade is raised and lowered. Does that sound correct?

Thanks again for sharing your knowledge.

-- Sam, Pittsburgh PA

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