Table Saw "upgrade" question

[Randal Cobb]

Hello all,

I am about to go out and buy a new TS. I've been looking at CL for a while and have only seen a few Uni's or PM66 saws going by. A few of them were not deals at all... way overpriced ($1500+) for CL or were stripped down for what they were asking for them (i.e., missing wings, no fence, etc.)... So, I'm thinking I need to go a different route.

My question is... if I opt to pick up a newer hybrid now, would it be possible to take out the smaller motor and replace it with at least a 3hp/220v motor later? Or, are all the "guts" of the saw designed to work with only the smaller motors?


If potentially upgrading a hybrid isn't really an option, I can still go down to Redmond Machinery and peruse their used/refurbed stock. I just wanted to find out first.

Thanks in advance!

[Mike SoRelle]

Generally speaking I think that would be a bad idea, the trunnions and blade carriage wouldn't be degined for the significantly increased torque, I'd say the only situation in which you might get away with it is in a model that offers larger motors as an option, but in those cases, I doubt you'd do better pricewise sourcing it yourself.

Personally I'd hold out for something like the PM2000 if that's really the size you're looking for

Mike

[Randal Cobb]

Yeah, that is my "gut-feel" as well... I was just curious if it was an option.

Thanks for the input!

[Chris Holder]

Hi Randal, I've always been a proponent of the "go as big as you can" philosophy, rather than trying to upgrade. Especially with something as central as a TS, the weight castings and motor size of most cabinet saws are truly an improvement over hybrids. I'm not knocking hybrids, but, you will probably spend less money in the long run if you hold out for what your really want now, rather than settling for an underpowered saw and later trying to upgrade.
I would go no less than 3 HP for my TS, and the more solid cast iron the better. There are reasonably priced Cabinet saws out there. Remember, a good TS can last a lifetime if cared for properly.

[Louie George]

Randal,

In addition to keeping an eye on CL you might also want to check out local auctions, I managed to snag a PM 66 that was missing rails and fence and was painted a very un-PM shade of brown, but was otherwise in very good condition, from one of my local school districts that had just upgraded to Saw Stops. By the time that I added a set of 50 inch Biesemyer, mobile base, rebuilt and repainted the saw and upgraded my shop to 220 I was still under the price that I would have paid for a hybrid. So there are some very good deals out there, but you may have to look for them but they are very well worth the effort. Good luck in your quest.

[David DeCristoforo]

$1,500 for a used uni is too much. You can buy a new "fully loaded" uni for $1,800 - 2,000. Typical resale price is 40 - 60% of new cost depending on age, condition and "features". It's quite possible that the CL sellers are fully aware of this and are simply "starting high" because they know that they are going to get "lowball" offers. That is exactly what I would do. Assuming that the machine is in good working condition and complete, I would offer $800 with the assumption that, after the inevitable negotiating, the price would settle at around a grand. If the saw is "mint" I would go as high as $1,200 but it would have to be "like new".....

[scott spencer]

Hi Randal - The Steel City hybrids have the infrastructure to handle a 3hp motor. One of their models actually has a 3hp motor, but all of their hybrids use the same trunnion, so it'd definitely be possible to start with a 1-3/4hp Steel City hybrid and upgrade the motor later on. No other hybrid I know of is rated to handle the bigger motor.

It's worth noting that even the 3hp Steel City hybrid still has the trunnion system of a hybrid, and it's very different than an industrial cabinet saw.

SC hybrid trunnion:
http://i6.photobucket.com/albums/y203/hewood/sawparts/SChybridtrunnion.jpg

SC industrial cabinet saw trunnion:
http://i6.photobucket.com/albums/y203/hewood/sawparts/sccabtrunnion.jpg

[J. Z. Guest]

I think scott spencer's advice is right on the mark.

I've also read that in 1.5 to 1.75 hp motors, folks generall feel like the saw is more powerful when wired & supplied from 240 V instead of 120. So you may not even feel the need to go to 3 hp.

If you do, it seems the saw is designed to handle it.

[Mike SoRelle]

I think scott spencer's advice is right on the mark.

I've also read that in 1.5 to 1.75 hp motors, folks generall feel like the saw is more powerful when wired & supplied from 240 V instead of 120. So you may not even feel the need to go to 3 hp.

If you do, it seems the saw is designed to handle it.

You know, I never understood that, technically there's no difference so I can only assume that

A. the wiring was undersized (or an extension cord was being used) and there was too much of a voltage drop during motor startup when that motor tries to pull a full 15A at 120

or B. 220 is bigger than 120 therefore it's a perception issue.

In alot of cases, it could very well be A, but I suspect there's a fair amount of B since we're talking about a pretty subjective comparison.

I read people saying that alot when they rewire, but the former commercial electrician in me just shakes his head every time I read it...


Mike

[Greg Cole]

I wouldn't go the hybrid route if you want a cabinet saw for the reasons already put up above. I shouldn't say much as I somewhat lament my contractor saw purchase some.... but it's very much pimped out & it works well. Just not quite what I want from a TS now, but it was more than I needed 4 years ago.:confused: I bought a General 50-185 when I really should have gone to the 650 style.
The rewiring from 110 to 220 makes the saw spin up MUCH faster, but that's about it.

Cheers.
Greg

[Tom Veatch]

...
My question is... if I opt to pick up a newer hybrid now, would it be possible to take out the smaller motor and replace it with at least a 3hp/220v motor later? Or, are all the "guts" of the saw designed to work with only the smaller motors?
...

Leaving aside the question of whether or not there's enough beef in the structure, there's another consideration - power transmission. Depending on the original power level, there may not be enough of an existing power train to get the additional horses from the motor to the blade. My 3HP cabinet saw uses a 3 sheave pulley and 3 V-belts to spin the arbor. That may be more than absolutely necessary, I don't know one way or the other. I'm reasonably sure that if you start from a single belt arrangement you'll need more than that if you actually start using the extra horses. And that could get messy. In fact, I'm thinking that's a bigger consideration than the strength/stiffness of the trunnion assembly.

My gut feeling agrees with the other posts. Save your pennies and keep looking until you find one that is closer to the size and power that you'll be happy with.

[scott spencer]

Leaving aside the question of whether or not there's enough beef in the structure, there's another consideration - power transmission. Depending on the original power level, there may not be enough of an existing power train to get the additional horses from the motor to the blade. My 3HP cabinet saw uses a 3 sheave pulley and 3 V-belts to spin the arbor. That may be more than absolutely necessary, I don't know one way or the other. I'm reasonably sure that if you start from a single belt arrangement you'll need more than that if you actually start using the extra horses. And that could get messy. In fact, I'm thinking that's a bigger consideration than the strength/stiffness of the trunnion assembly.

My gut feeling agrees with the other posts. Save your pennies and keep looking until you find one that is closer to the size and power that you'll be happy with.

Hi Tom - You raise a good point about the belts and pulleys. The manual for Steel City's 3hp hybrid (model 35675 (http://steelcitytoolworks.com/products/35675/35675_manual.pdf)) shows an alternate belt and pulley for the 3hp motor vs the 1-3/4hp version....I'd assume those are made to handle the additional stress, and should be a low cost easy switch.

Overall, I agree with you... it'd seem easier and advantageous to go with the industrial cab saw first, but that scenario may not be in the cards for the OP now.

[scott spencer]

You know, I never understood that, technically there's no difference so I can only assume that

A. the wiring was undersized (or an extension cord was being used) and there was too much of a voltage drop during motor startup when that motor tries to pull a full 15A at 120

or B. 220 is bigger than 120 therefore it's a perception issue.

In alot of cases, it could very well be A, but I suspect there's a fair amount of B since we're talking about a pretty subjective comparison.

I read people saying that alot when they rewire, but the former commercial electrician in me just shakes his head every time I read it...


Mike

Hi Mike - I've switched two of my saws to 220v. The first one (GI 50-185) got minimal improvement, the second one (Craftsman 22124) had more notable improvement on 220v. Both had notably faster start ups....I can't help but wonder if what is perceived as "more power" is really faster recovering from bogging down...or maybe it's just another possible cause in addition to those you mentioned.

[Steven Hardy]

You know, I never understood that, technically there's no difference so I can only assume that

A. the wiring was undersized (or an extension cord was being used) and there was too much of a voltage drop during motor startup when that motor tries to pull a full 15A at 120

or B. 220 is bigger than 120 therefore it's a perception issue.

In alot of cases, it could very well be A, but I suspect there's a fair amount of B since we're talking about a pretty subjective comparison.

I read people saying that alot when they rewire, but the former commercial electrician in me just shakes his head every time I read it...


Mike

Technically there IS a differance..potentially a huge differance.
The differance occurs in transmission line losses as you increase current.
As you double the current (going from 220 to 110),you might think that power loss (in the wire)is the same.
This is incorrect as current losses thru resistance are non-linear.
The only way to explain accurately is the simple formula
Power equals resistance times current squared.


Five cases to consider all with 1 ohm resistance(with is the FIXED value)
1 OHM times 1 amp(squared) = 1 watt
1 OHM times 2 amp(squared) =4 watt
1 OHM times 3 amp (squared) =9 watts
1 OHM times 4 amp (squared) = 16 watts
1 OHM times 5 amp (squared) = 25 watts

Do you see the NON LINEARITY of current /power loss yet??
notice that when we tripled current the power loss was ninefold????

Now IF the wire was a short run on HEAVY guage,high quality wire ,maybe the resistance is only .1 Ohm and the losses only .1 thru 2.5 watts. In the worst case (of the examples) the loss of 2.5 watts is negligable BUT still a NONLINEAR loss .The value of halving the current by doubling the voltage is greater than you would expect,especially if your 2-300 feet from the transformer(MUST BE CONSIDERED DUE TO NON LINEAR LOSSES)).

[Mike SoRelle]

Technically there IS a differance..potentially a huge differance.
The differance occurs in transmission line losses as you increase current.
As you double the current (going from 220 to 110),you might think that power loss (in the wire)is the same.
This is incorrect as current losses thru resistance are non-linear.
The only way to explain accurately is the simple formula
Power equals resistance times current squared.


Five cases to consider all with 1 ohm resistance(with is the FIXED value)
1 OHM times 1 amp(squared) = 1 watt
1 OHM times 2 amp(squared) =4 watt
1 OHM times 3 amp (squared) =9 watts
1 OHM times 4 amp (squared) = 16 watts
1 OHM times 5 amp (squared) = 25 watts

Do you see the NON LINEARITY of current /power loss yet??
notice that when we tripled current the power loss was ninefold????

Now IF the wire was a short run on HEAVY guage,high quality wire ,maybe the resistance is only .1 Ohm and the losses only .1 thru 2.5 watts. In the worst case (of the examples) the loss of 2.5 watts is negligable BUT still a NONLINEAR loss .The value of halving the current by doubling the voltage is greater than you would expect,especially if your 2-300 feet from the transformer(MUST BE CONSIDERED DUE TO NON LINEAR LOSSES)).

You're correct about the non-linearity

Still assuming code compliant wire sizing and typical house sizes, until you are approaching the current capacity of the circuit and infrastructure, you're talking about a relatively negligible loss in the terms of what we're talking about.

Perhaps I'd have been better off to say that there's no difference in the capacity of the equipment regardless of it's input voltage. The spool up speed is faster just because of the interaction of the windings and the rotor, but the ability to do work is limited by the design and rating of the motor, not on it's supply voltage.

[Steven Hardy]

You're correct about the non-linearity

Still assuming code compliant wire sizing and typical house sizes, until you are approaching the current capacity of the circuit and infrastructure, you're talking about a relatively negligible loss in the terms of what we're talking about.

Perhaps I'd have been better off to say that there's no difference in the capacity of the equipment regardless of it's input voltage. The spool up speed is faster just because of the interaction of the windings and the rotor, but the ability to do work is limited by the design and rating of the motor, not on it's supply voltage.

Well, I think we are mostly in agreement. Consider this..and I shall add that I have not followed code since I built my house and Installed the wiring under supervision of an electrician...the code deals primarily with safety...not performance of induction driven motors. A 20 amp circuit could be simply 5 feet from the panel or in some cases 30-40 feet and still be in code compliance . AS the heat is dissipated over a longer elements of wire ,its still safe and compliant. I would venture an educated guess that many 1hp motors (as installed) ,are only delivering 3/4 hp under load due to line losses,switch losses,and power cord losses...even with code compliance.

[Mike SoRelle]

Well, I think we are mostly in agreement. Consider this..and I shall add that I have not followed code since I built my house and Installed the wiring under supervision of an electrician...the code deals primarily with safety...not performance of induction driven motors. A 20 amp circuit could be simply 5 feet from the panel or in some cases 30-40 feet and still be in code compliance . AS the heat is dissipated over a longer elements of wire ,its still safe and compliant. I would venture an educated guess that many 1hp motors (as installed) ,are only delivering 3/4 hp under load due to line losses,switch losses,and power cord losses...even with code compliance.


Well, disclaimer here that my electricians license expired over a decade ago, but beyond losses within the design and implementation of the equipment itself, assuming the ampacity derating was done correctly which in turn determined the conductor sizing, the supply shouldn't be impeding the tools potential to operate.

And yes, the NEC is part of the NFPA (national fire protection association) governed codes which are primarily concerned with life safety issues, in the process of complying with that there is some assurance of capacity that you get as a side benefit. It can certainly can be said however that some provisions of the NEC intentionaly sacrifice capacity/effeciency for the sake of safety which I suppose at the end of the day, you can't enjoy any of this stuff while dead or if it all burns up, so I think that counts as a good thing :)

I think we do agree on the major points, wonder what the 'normal' effeciency rating is for a non-specialty induction motor is, I'd bet for the stuff we're talking about it's probably 60%, I know the effeciency changes with load, but I've long since forgotten any of the stuff I picked up doing industrial electrical jobs.

Mike

[Bruce Wrenn]

Leaving aside the question of whether or not there's enough beef in the structure, there's another consideration - power transmission. Depending on the original power level, there may not be enough of an existing power train to get the additional horses from the motor to the blade. My 3HP cabinet saw uses a 3 sheave pulley and 3 V-belts to spin the arbor. That may be more than absolutely necessary, I don't know one way or the other. I'm reasonably sure that if you start from a single belt arrangement you'll need more than that if you actually start using the extra horses. And that could get messy. In fact, I'm thinking that's a bigger consideration than the strength/stiffness of the trunnion assembly.

My gut feeling agrees with the other posts. Save your pennies and keep looking until you find one that is closer to the size and power that you'll be happy with.When the Uni was designed in the 1930's, it took three belts to transmit the power with certainty. Times have changed, and V- belts have also. Todays belts can do so much more than belts of old. Look no further than under the hood of your car. A single belt now drives the alternator, AC compressor, PS pump, and water pump. Seldom will you see a belt break on todays machines, even though they are worn thread bare. Do some research using search function both here and at other forums for the Craftsman 22124. I don't recall anyone saying they were unhappy with this saw. A few had a chance to get a used Uni, or PM 66 and parted with their 22124's.