I have an older Rockwell table saw that I’ve been pretty pleased with, up until this weekend anyway. It’s a 10″ model with at 1.5 HP motor. Got a new Freud Diablo ripping blade, which has done pretty well up to Saturday. Cuts clean anyway.
Anyway, Saturday, I need to rip some 2×6’s into parallelagrams. Cut a 30° bevel on each side of the board. Figured no big deal, just do it. My saw didn’t have anywhere near enough pep to do it. Even in 2 passes, I had to go real slow. And stop at times to let the motor wind back up. Entirely bogging the motor down was easy. It’s a belt drive contractors style saw.
Is this normal, or might my motor be on its last legs? Any way to get that tested?
My wife is helping me. She gets it half right when she says, “are you sure you can build that hardwood furniture you’ve been talking about with this saw?” Then she blows it, “maybe you’d best make it out of softwood.”
I told her maybe I’d just have to buy a better cabinet saw first, but she wasn’t buying it. Oh well, at least she was 1/2 right. She’s come a long way in 10 years.
Maybe it’s time to look for a 3-5HP cabinet saw?
Replies
A couple of things come to mind right away, aside from the sharpness of the blade and integrity of shop wiring and belt drive. If the motor is configured for 120V operation, you may have lost one of the main windings (if it's 240V, it won't run at all). Check the connections inside the junction box. If there are wires wirenutted together, gently pull them, one against the others, to see if any pull out. Or better yet, just undo and redo them, one at a time. If there are the little metal links on studs instead, check the nut tightness. That motor may also have a run capacitor in addition to the start capacitor, and if its dead or dying, the motor will still run, but not produce full power. A motor shop could check all this out, and compare DC winding resistance and capacitor health, in a matter of minutes, if you're not inclined to do it yourself. Hope this helps.
Be seeing you...
Good suggestions. Since I had the starting capacitor replaced by a motor shop when I got the motor, I hope they tested it. But am not sure they did. No run capacitor.
They did wire it to run the wrong direction, and I reversed it, so if there are loose connections, I did them. It is wired for 120AC.
Come to think of it, my old really wimpy craftsman saw always bogged. When I first got this one, I set my miter gauge at 45°, tilted the blade to 45° and cut slices off a 2x4 without any sign of binding at all.
Of course, that was crosscutting not ripping and with a different blade.
Something's changed, hopefully the motor's not toast.
I'll check the connections, thanks.
It's not the start capacitor that's causing bogging while you're cutting. It's not in the circuit once it's running. If loose motor connections are not the cause, take it to a motor shop for a quick ringing out of the windings. You may have burned one or both of the run windings (not as many turns due to shorting - it happend to a 3-phase RAS of mine), or one may have lost continuity. But do make sure the belt drive is sound before you spend money at a motor shop. It could be something simple like a piece of scrap preventing the motor weight from tensioning the belt, or the belt is shot and running in the bottom of the groove. Good luck.
Edit: If this is the Rockwell table saw motor you mentioned a while back, it may be a Baldor with a Rockwell nameplate. If that's the case, the leads in the j-box may be metal tagged with numbers, which makes it easy to test the windings. If it is, I'll send you a schematic for that motor, and you can check it out yourself with a multimeter. The manual may also have a schematic, though doubtful.
Be seeing you...
Edited 3/4/2003 2:19:55 PM ET by Tom Kanzler
Thanks! I understand it's not the start capacitor. Just noting it doesn't have a run capacitor, which you'd mentioned. Yep, same motor. Belt is in good shape. It's tensioned by the motor weight on a pivot. Everything's working well. Thought maybe it was slipping at first, but belt looks brand new. No squealing or other signs of slippage. And you can actually hear the motor stop.
I'm surprised you remember me mentioning the motor. I'll check on the wire tags, but don't remember any. There was a decent schematic of saw wiring for different voltages and directons, but that's about it. Don't have a manual.
I'd appreciate the schematic. I'll write down any info on the motor plate if that'd help you know what motor it is. Rockwell didn't know. The motor shop guy said he had a terrible time finding a start capacitor. Rockwell couldn't tell him a thing about the motor.
Are burned windings fixable? The powering out occurred as soon as I started cutting. Did great cutting 3/4 particle board and some 3/4" pine the other day.
If I'm understanding you, the problem is intermittent, which would suggest a loose connection. I've attached a schematic of a Baldor motor wound like yours. You can identify the start winding leads easily because they are the ones you reverse to change motor rotation. The other four are the run winding leads. They should measure about 1.5 ohms or so each, and they should be the same. If you get no continuity, you have the probes on both windings; pick another wire OR the winding is broken. Just don't mix up which ones go where. If you get really goofy results, there is a short or open circuit somewhere. If you get really low readings, it's a good bet the windings are shorted, but then you will probably also see continuity between the windings. There shouldn't be any continuity between each individual winding once the leads are separated. If they both measure somewhere between 1 and 2 ohms, it probably was just a loose connection. Clear as mud?Be seeing you...
The problem isn't really intermittent. Just doesn't due well with big heavy angled cuts. Doesn't bog down at all doing a straight cut. Just thought of something. I need to do an angled cut with the miter gauge. Maybe, when I angle the blade it's no longer parallel to the fence. I'll try some angled cuts w/o the fence. Not sure how to fix it if that's the problem though.
I had a few minutes last night.
I tried ripping another 2x4 at 30? angle w/ the 6' extension cord I normally use. No difference. It's a very heavy duty outdoor cord, but contrary to my previous belief, is only 16 gauge. I'll have to move my saw to try it w/o a cord.
Plugged it in to the garage door opener circuit, which has 2 150 watt bulbs on it also. Starting the motor majorly dims the lights. Then they resume brightness after the motor hits speed.
Decided not to blow the breaker by bogging the motor down w/ the lights on. This was also with the short extension cord.
Haven't had time to test the motor windings, though I've printed off the advice, and will see if I can figure out how to do this. Maybe Saturday, if I can find time. Also gonna test resistance in the saw power cord.
For those who suggested a Powermatic or similar tablesaw. That's just a dream right now. There are a dozen other things I'd buy first if I had that type of money available. Someday I may get such a nice saw. Though knowing me it'll be an old one that's been sitting in a shed for 20 years unused and needs major work to get going again. I'm a cheapskate. Kind of have to be when you don't use credit to buy stuff.
Oh. . . . . I thought it was a new phenomenon, and intermittent. I glazed over the probable cause in the first line of my first post in this thread. In that case, Booch has probably called it right. It seems to be common for (standard) garage circuits to be only 15A with 14 gauge wire, so voltage drop will rear it's ugly head with that 1.5 hp motor pretty readily.
The only real fixes are 1) rewire with a 20A circuit, and use 10 gauge (or even 8 gauge), if the run is long, to minimize voltage drop under load, or 2) rewire for 240V operation, in which case 15A would work fine, though I'd use 20A in anticipation of larger tools. I'd use 10 gauge wire, also, so when you get that PM66, you'll be all set to change out the breaker for a 30A (PM66's with 3 hp Baldor motors draw more current than Unisaws with 3 hp Marathon motors). You could also 3) put a subpanel there and keep the shop wiring short, which is the best of all IMO, but that's up to you. And don't forget, as someone else mentioned, to keep the blades sharp, and consider a thin-kerf type.
Other than that, forget all that other stuff I posted.Be seeing you...
Well, all the circuits are 12 gauge, and all on 20 Amp breakers, so that's not a problem. But I think I've just decided it's time to run a 220 circuit. I have some 3 and 4 pin twist lock plugs, both ends, sitting in a drawer. A local hardware store discontinued them a couple years ago, and priced them at $.25 ea. I'd have to buy some wire and a breaker, but not much else.
Using 10 gauge wire is a good idea, just in case I ever get a better saw. They're 30 Amp plugs anyway. Though I'll hopefully have built a shop by then. Unless I find something really cheap, a big saw is way down the road.
Still wonder if my blade isn't parallel to the fence when it's angled. Think I'll see if I can figure out a way to measure this.
Anyway, have a good weekend.
Bye now.
Billy,
If you are using the table saw's splitter, it is highly possible that it is trapping the work piece against the table top during the cut. This would cause the progression of the cut to become very difficult, and in turn could cause the motor to bog down.
You may want to check out the splitter's alignment before attempting a major motor rewire.
Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.
Thanks for the advice. Don't remember if I mentioned it, but it's not the fence. Same problem cutting with the miter gauge.
What's a splitter??
Just kidding, my saw doesn't have such an animal, though I should add one.
I do a fair amount of wiring. So, rewiring the saw wouldn't be a big deal. Biggest pain is to get the new wires into the attic, but is really a pretty easy project. Just not sure it'd make a real difference. But, for the little time and cost (50-60' of 10-2 wire) I'll probably do it one day, just to see. May just run conduit and put in 12-2 for now, that I already have.
Edited 3/10/2003 12:08:45 PM ET by BILLYG83440
There is a serious clue in his statement regarding the bogging when cutting angles. Given the blade's tendency to want the draw the wood into it, cutting an angle automatically causes creep and bonding which equals additional load unless is lock-solid on a sled or on clamped in a well-design miter.
Of course that is in addition to other load factors already discussed.
For what it's worth.
Doug
Exactly what do you mean by 'creep and bogging?" I've never heard either term used in woodworking before.
I've also never heard of a table saw wanting to self-feed, though it's obvious radial arm saws do.
It's a new blade, maybe I'll put my old craftsman blade on and see if it changes things any.
Get a planer blade. the thinner the cut the less the effort (read horsepower) required to make the cut. They are cheap and good. The other alternative is the "LM" teflon coated freud thin rim carbides. almost as fast as the planar blade.Jack of all trades and master of none - you got a problem with that?
Billy,
When you cut accross the grain at less or more than a 90 degree angle, the spinning blade wants to pull the piece into it which causes the material to bind at the back of the blade. Bogging is simply an expression related to a motor down due to excessive load. If you miter pieces without clamping them securely, measure the angles and you will notice that they can be slighly off due to the face of the cut not being perfectly straight. Obviously, the harder the wood the more pronounced the effect. This is caused by the wood creeping into the blade as the blade moves through the cut. The steeped the angle of cut, the more pronounced the creep.
Doug
You are dreamin on the Powermatic. Sorry to say but you need a new circuit. In the words of Scottie " Capn'... I need more power!"
2 @ 150 watt (on a garage door opener?) Did you read the tag on the opener? Mine says 2 @ 60 watt. nevermind the opener is over served with power if the TS and whatever else is on the circuit.
WEST VIRGINIA LAW* watts=voltsxamps W=VxA
Do some calculations.
*name courtesy of a friend in stage lighting Jack of all trades and master of none - you got a problem with that?
Motor rewinding is pretty common but it will cost 3/4 of a new motor. Plus you need to be patient. Take it in for an estimate at the local shop found in the yellow pages under motor rewinding.Jack of all trades and master of none - you got a problem with that?
It's also a possibilty that your fence is out of whack, or the boards you are ripping are bowed or warped. These conditions will bog the motor down also.
You didn't say what kind of wood you were cutting but in any case I have gotten into the habit of using the smallest blade possible to make whatever cut I am making. I have a grossly underpowered Shopsmith and I use 9", 8 1/4" and sometimes even 7 1/4" blades to make the cutting easier and lengthen the life of the motor. DeWalt makes some incredible 8 1/4" very thin kerf blades that cut ANYTHING like butter. I wish I had discovered this trick years ago as I too fought with the kinds of problems you are having.
Good Luck
Spend your money and send the old TS my way. All you really need is new shives or pulleys. Change them out to Cast Iron or steel pulleys. At about 10 to 15 bucks each you replace the one on the arbor shaft and the one on the motor shaft. You can even use the old belt for that matter. Of course a new belt would help as well
Pot metal pulleys have little tooth for the rubber belt. CI or steel machined pulleys bring an old dog to life. I've done it to a 1 hp craftsman and a 1.5 HP Rockwell contractor saw. I still use the saws.
Thanks everyone for the response.
I printed off the schematic, but didn't have a chance to do anything with it.
I didn't get much of a chance to mess with the motor last night. I can't read much of the name plate w/o taking the motor off. The wire nuts are all tight. The fence is square. I was cutting pine 2x material.
I think I accidentally plugged it into a smaller gauge extension cord then usual. I usually use a heavy gauge cord. Until rewiring my garage, a short extension cord is mandatory. But, I think it got plugged into a 25' 16 gauge cord by mistake. It draws 15 amps, way too much for that size cord. Couldn't test my theory by making a cut with the kids being asleep. I'll plug it in right and test it tonight.
"...I think it got plugged into a 25' 16 gauge cord by mistake. It draws 15 amps, way too much for that size cord."
That cord is good for about 3% voltage drop all by itself (at 15A) on top of all other wiring and connector losses, and a lot more when you're bogging the motor and it's drawing excessive current. Yep, that'll do it.Be seeing you...
I'm really curious why pulleys would make that much of a difference.
I understand why machined pulleys, and a link belt would help dampen vibration. My saw doesn't have much of a vibration problem, but it's probably something I should do.
I haven't had any problem with belt slippage, so I am already getting full power transfer. Though I understand cheap pulleys have more problems with this.
Do better pulleys have other benifits then just reduced vibration? Am I missing something?
Well things are mixed here.
As i read your writeup, I see the 120 volt wiring setup and think this may be more to the issue. You are probably pulling the voltage low by putting such a large load on the 120 line. If there is any kind of distance to the wire, any resistance in the connections, or a combination then the resistance in the circuit will make your motor starved for the power it gets from the volts.
If you have the cahoneys, skill with a VOM check the wires at the motor on startup. I'd bet the voltage drops real low when you turn on the motor. You might even be able to tell that by plugging in a lightbulb into the same duplex outlet. if the light dims appreciably then there is something pulling the voltage low. It could be wiring, it could be a bad winding.
As for the smooth pulleys, It is my peeve because I have upgraded 2 motors to a larger size and even to 220 (TS & Shaper). In the end the biggest difference was the pulleys as they delivered the torque to the blade. Any slip made the problem of getting power to the blade worse and worse. It is sort of like slipping on the road after a snowstorm. You are making progress but energy is wasted. Steel & CI have more friction in the groove. They are generally machined / turned to shape. When they rust a bit there is even more tooth to drive the belt.
PS I don't even use a link belt. I just use the std V groove belt and it makes a difference.Jack of all trades and master of none - you got a problem with that?
Per given energy input, less vibration equals more work. Vibration is wasted energy!
I have a 1946, Delta, tilting table saw. It has a belt way over 40" long. I upgraded from single, pot metal pulleys on both motor and arbor to machined double grooved on both. It made a substantial difference in power, especially when ripping!!
It doesen't actually actually increase the power of the motor (I don't think), it just transmits it more efficiently to where it needs to be.
On the other hand, boards whose edges are not straight, less than keen blade, table friction (rust or corrosion) and other gremlins may be causing the problem.
I have also heard many times (and I firmly believe it) that a good blade will make a crappy saw do wonders. Maybe for that heavy of a rip, on that saw, you need a specialty blade.
My 2 cents.
Mack
Makes sense.
My saw table could definately use a good wax job. Good pulleys sure wouldn't hurt either.
Gotta try it with the right power cord first. If I'm lucky, that's the main culprit.
Billy,
If all else fails and you do buy a new saw, I HIGHLY recomend the powermatic 66! I recently took the $2,000.00 plunge and absolutely love that saw!!!! It is a super quiet, very accurate powerhouse! I can't say enough about what a joy it is to use. It is a bit pricey but ( In my opinion) worth every dime!
Miami
Yes it is time for a cabinet saw! If you value you time, energy, and fingers, buy a cabinet saw. I have overworked saws from time to time and it is a miracle that I haven't been hurt. Considering what fingers cost these days, a saw is a bargain.
I'm real tempted, gonna try to save up some money and keep an eye out for a decent used saw.
I thought 1.5 HP would be perfectly adequate, but it's not too much harder to stall then the old 1/2 HP Craftsman saw I used to use.
Still think I'll have the motor shop test this one and see if it's any good or not. Sure seems like it used to have more power.
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