Deciding whether to restore my old unisaw

[Bill Dufour]

I like to paint the interior of such machine cabinets gloss white. Latex paint is plenty good enough since you will seldom see the inside. That white paint makes it brighter inside with a flashlight looking for dropped blade nuts etc. Not really needed but I am painting all the arbor parts including every thing that moves up and down with the arbor light green. Everything that tilts only is being painted teal. All the parts that do not move will be white.
that way if something is sticky and can stand on my head and see what color part I should be thinking about cleaning and lubing with some dry lube of some kind.
Bil lD

[andy bessette]

I like to paint the interior of such machine cabinets gloss white. Latex paint is plenty good enough...

That would knock off at least half the resale value for me.

[Jeff Heath]

Unisaw's have no resale value. You can buy them for a few hundred bucks anywhere, and certainly on OWWM classifieds. They are a really good cabinet saw, though, so set the saw up the way you like. It's not the kind of machine you're going to make money off of in a flip, and I seriously doubt 95% of the potential buyers down the road are going to care less if the interior is painted white.

Clean the saw up, change the arbor and motor bearings (all very inexpensive), and you'll have a terrific 10" cabinet saw. My first cabinet saw, for 10 years, was a vintage Unisaw. I paid $300 for it at a barn sale 30 years ago, and cleaned it up. I made furniture and cabinets with it for 10 years and made a ton of money using it. They are fine saws to start out with, until you want to upgrade to bigger and better, like a slider.

[Jacob Mac]

I would clean it, replace the bearings and get back to making furniture. If down the road you love the hobby and want something better/different, then go get it.

[Mark Wooden]

I didn't see it mentioned, but older motors were rated differently than they are today; your 1 hp will have a much better power curve than a newer motor and probably out perform a 1.5hp new motor. I use a 1hp Walker-Turner tablesaw a lot, rips 8/4 white oak just fine with a good full kerf rip blade. Would I use it to rip 1000 bd ft of it? No, I have a 5hp Oliver for that.
I'm with Jeff Heath, the Uni is a very good, solid, easy to work on saw that has been equipping home and pro shops since the 1940's. Absolutely worth replacing worn parts, motor up grade if needed. I'm actually replacing a 5hp with a 2hp (3 to 1 phase)in one soon to use a a site saw. Doubt I'll miss the hp.
What I'm getting at is don't base the amount of power you require on a motor tag or what others have, but on your needs.

[Rich Engelhardt]

I'm not really a ""hobbyist"" per say, when it comes to woodworking. I do it more as a means to an end. I rehab and restore older 1930 to 1960's era houses.
Most of the same equipment is used for both though.

Anyhow,,,having said that,,,I for one have less than zero interest and/or desire to restore, repair, resurrect or rescue old(er) tools. Since my workspace is my garage and driveway, I have between late March and mid-October to get as much use as possible out of my equipment. Anything, such as wasting my time and space, on trying to bring back some piece of equipment just isn't going to happen...#1-beaucse as I say - I consider it a waste and #2 - I dislike - I'd even go so far as to say, I hate, working on equipment. I had my fill of that working on printers when I got into the IT field.

Don't mean to brush anyone's fur the wrong way - - and I appreciate those people that do get as much, if not more enjoyment out of working on the tools instead of the wood.....I'm just not one of them.

[Mike Henderson]

I didn't see it mentioned, but older motors were rated differently than they are today; your 1 hp will have a much better power curve than a newer motor and probably out perform a 1.5hp new motor.

I'm afraid that's not correct. We've known how to test motors for HP for a long time and the definition of a HP has not changed. In any case, there's no free lunch. The energy for the HP has to come from somewhere and it comes from the voltage and current of the motor. If anything, old motors were not as efficient as newer motors so I'd actually expect that they would take more current (at a particular voltage) to produce the rated HP than a new motor.

Some people glamorize old things and I think this belief is part of that glamorization.

Mike

[Some of the old Unisaws had low horsepower repulsion-induction motors. On those motors, if you started to stall the motor, which was easy to do because the motor was low HP, the starting system would kick in and add some power. The problem is that the motor was not designed to operate that way and it was drawing excessive current when it was pushed that way. Also, the starting system only kicked in when the RPMs of the motor went down quite a bit so you were attempting to cut with a blade not at full speed.

Rather than use a motor that way, you'd do better to just install a motor with sufficient HP. That way, you won't stall the motor and you'll be cutting at the RPMs that the blade was designed for.]

Mike

[Scott Hearn]

I like to paint the interior of such machine cabinets gloss white. Latex paint is plenty good enough since you will seldom see the inside. That white paint makes it brighter inside with a flashlight looking for dropped blade nuts etc. Not really needed but I am painting all the arbor parts including every thing that moves up and down with the arbor light green. Everything that tilts only is being painted teal. All the parts that do not move will be white.
that way if something is sticky and can stand on my head and see what color part I should be thinking about cleaning and lubing with some dry lube of some kind.
Bil lD

That's actually a good idea! Wish I had thought of it when I had mine apart.

[Allan Speers]

I'm afraid that's not correct. We've known how to test motors for HP for a long time and the definition of a HP has not changed. In any case, there's no free lunch. The energy for the HP has to come from somewhere and it comes from the voltage and current of the motor. If anything, old motors were not as efficient as newer motors so I'd actually expect that they would take more current (at a particular voltage) to produce the rated HP than a new motor....

[Some of the old Unisaws had low horsepower repulsion-induction motors....

Hey, Mike, Just as a point of interest: (as I have no idea)

Could it be that some motors have more torque than others, for a given HP?
Torque is what gets the work done, so if that were true, it might account for the love for those old I-R motors.
(Or maybe it's just those rose-colored glasses.)

For instance, if a less-efficient motor uses 15a for 1.5 HP, and an efficient motor uses only 12a for its 1.5 HP rating, could it be that the first motor has more torque? It seems to me that more current would do exactly that, unless it's simply lost as heat.

[Mike Henderson]

Hey, Mike, Just as a point of interest: (as I have no idea)

Could it be that some motors have more torque than others, for a given HP?
Torque is what gets the work done, so if that were true, it might account for the love for those old I-R motors.
(Or maybe it's just those rose-colored glasses.)

For instance, if a less-efficient motor uses 15a for 1.5 HP, and an efficient motor uses only 12a for its 1.5 HP rating, could it be that the first motor has more torque? It seems to me that more current would do exactly that, unless it's simply lost as heat.

No, the definition of HP is torque times RPM times a constant factor. So all motors running at 3450 RPM will have the same torque at the same HP (by definition). If it had more torque, it'd have more HP.

At any given RPM, all motors will have the same torque at the same HP.

Also, torque does not do work. Torque is just a force. The measure of work is HP, which is force in motion (force times distance). To actually remove wood (which is what a saw blade does) you need HP, not torque.

Mike

[And yes, with a less efficient motor, the excess current, beyond what is converted to HP, goes to heat.]

[To illustrate the difference between torque and HP, consider the case where you lock the rotor on a motor and try to start it. There will be a torque applied to the rotor but the rotor won’t move and no work will be done. ]

[Bill Dufour]

Before you remove the table spray paint the four mounting points so you can match them up later. Once the tabletop is back on the saw spend 30 minutes adjusting the top to be parallel to the blade. Not doing this can cause kickback and poor crosscuts. Then adjust the fence so it is parallel to the blade or kicks out a fraction at the far end.
I forgot to do this, repainting any way, so I will be spending a long... time getting it back exactly where it needs to be.
Jumping ahead and doing a early test cut could be very dangerous to you fingers/eyes/face and/or life.

[Allan Speers]

Also, torque does not do work. Torque is just a force. The measure of work is HP, which is force in motion (force times distance). To actually remove wood (which is what a saw blade does) you need HP, not torque. ]

I'll agree with everything else, (AND THANKS) I'm not ready to buy this part, just yet.
Torque is what keeps the motor from bogging down when you lay into a 4/4 piece of Ipe. (no?)
And isn't THAT what really matters, when a guy is wondering if his 1.5 HP tablesaw has enough "power?"

Like with a car: HP gets you top speed, but "torque wins races," as they say.

So..... no?

[Patrick Walsh]

Maybe true for most and I won’t get to into it.

I often bog down a 5hp saw when working. Sure slowing down feed rate all but solves the issue but you know I’m not much for underpower.

But you know if the saw suits you now and you feel like getting dirty I say go for it....

[Mike Henderson]

I'll agree with everything else, (AND THANKS) I'm not buying this part, just yet.
Torque is what keeps the motor from bogging down when you lay into a 4/4 piece of Ipe. (no?)
And isn't THAT what really matters, when a guy is wondering if his 1.5 HP tablesaw has enough "power?"

Like with a car: HP gets you top speed, but "torque wins races," as they say.

So..... no?

No, it’s HP that does the work when cutting wood. Torque is just a force. And all motors of equal RPM and HP have the same torque.

Those old motors don’t have any more torque than an equivalent modern motor. If they had more torque, they'd have more HP. Look up the equation for HP of an electric motor and you'll see that HP is directly related to torque (at the same RPM).

Mike

[Here's the equation for HP. HP = (Torque (in lb feet) * RPM)/5252 You can check this at Wikipedia ]

[And just another note, small (about 1HP) single phase induction motors have an efficiency of perhaps 70% to 75% at full load. The efficiency gets better for larger motors (say a 50HP motor). What we might call "old motors" might be a bit less efficient. More recently manufactured motors have gotten more efficient - the designers have made small improvements in efficiency with each generation of motor. The maximum efficiency is usually not at full load but at about 75% of full load.

3 phase motors tend to be more efficient than single phase motors at the same HP rating.]

[Just one more side comment: Universal motors can provide decent (real) HP in a small package because of the high RPMs that they operate at. Their small size limits the amount of torque they can produce, but the high RPMs can compensate for that. If you can double the RPMs, you can produce the same HP with half the torque. But the people who make those universal motors do not report the real HP of those motors - they report a fake, stall HP.]

[Mark Wooden]

I'm afraid that's not correct. We've known how to test motors for HP for a long time and the definition of a HP has not changed. In any case, there's no free lunch. The energy for the HP has to come from somewhere and it comes from the voltage and current of the motor. If anything, old motors were not as efficient as newer motors so I'd actually expect that they would take more current (at a particular voltage) to produce the rated HP than a new motor.

Some people glamorize old things and I think this belief is part of that glamorization.

Mike

Mike

Well, not being an electrical engineer, not interested in whats tested or not and I can only report on what I experience. Not glamorizing anything either. I just own and use a mix of newer and older equipment and can tell when one is doing better than another; and can also see and feel the difference in build quality. I do know my re-built machines give me less trouble, and it ain't luck or happenstance.
Maybe its an acquired taste and feel, don't know, and it ain't for everyone.
I still say tune the saw up, its worth it.