What did I do wrong

[Greg in Maryland]

Hi

Tonight I was ripping 1 3/4 x 4 1/2 x 10 inch hard maple into a 1 3/4 x 1 3/4 x 10 inch strips. I did a total of two cuts and had a lot of problems. I was using the rip fence with push blocks and the blade was set so that the bottom of the teeth just cleared the maple. The blade is factory original. The maple had been planned and jointed, so it was very near square.

So here is what happened on my BT3100:

1) The saw really labored through the wood. I was trying to have a steady feed rate without pushing too hard but it really slowed down.

2) The saw burned the @#$@#$ out of the wood, to the extent that the smoke detector just outside the basement went off. Obviously, by the smell I knew the saw was burning the wood, but because of the noise of the saw and vacuum and the fact I wear ear muffs, I did not hear it until everything shut down, nor realized it was so bad.

3) Of more concern the circuit breaker tripped during the middle of each cut when the saw was struggling. That was a !@#$!@# moment when I initially thought I fried the motor. Fortunately, that was not the case.

The saw is connected to 15 amp outlet with a dedicated circuit breaker (it use to be an outlet for a refrigerator). In addition I used one of those Sears auto switches that turns on my vacuum when the table saw is turned on. This is rated at 15 amps as well. The saw was connected to directly the outlet, not via an extension cord.

I have a 200 amp panel with 19 single circuit breakers and 3 double breakers. I cannot tell how many amps each circuit breaker is rated for, so all I can do is count.

What's going on? Is the load from the saw too great for the line and/or the circuit breaker? I can have another circuit breaker added if that would improve the situation.

What are other's experiences with maple of this size on the BT3100? Should the BT3100 be able to handle this or is this a common limitation?

What work arounds are available to make the cuts? I have 18 more and need to figure something out. One thought I had was to set the blade height around an inch, run the piece through the saw, flip it upside down and finish the cut that way.

Any thoughts or suggestions would be greatly appreciated.

Thanks.

Greg

[Warren]

You don't say: Is the blade sharp? Is it clean? Is the rip fence in allignment?

These are the only suggestions I have. A properly tuned saw with a sharp blace should handle this job with no problem. It certainly sounds like an allignment or blade problem, not a load problem.

[cgallery]

A couple of things. First, the combination of the vac and the saw on a single 15A circuit is too much.

Next, hard maple is, well, hard. 1-3/4" hard maple would be a challenge for all but the largest contractor/cabinet saws. I would suggest making sure your blade is absolutely sharp. Then, cut 1/2 the thickness at a time. I may even make three passes.

Also, make sure your fence is properly aligned. Does the wood seem to feed fine at first but start to slown down a lot once the front of the board starts to clear the back of the blade? If so, the fence may be out of alignment and causing binding at the back of the blade.

Finally, I believe a rip blade can help with ripping thick stock like this. Although a sharp multi-purpose should be up to the task.

I don't have a lot of maple, but I do have some maple plywood. At only 3/4" thick (all seven plys are maple) this is some real tough wood. If I had to quantify it, I'd say my saw works twice as hard cutting it as it does baltic birch plywood of the same thickness.

[cgallery]

Oh, and one more thing. In the future, when this sort of thing happens, STOP! Your saw is telling you something. Burning wood enough to set off smoke alarms and tripping circuit breakers is time to come here, ask questions, and research a little. SAFETY FIRST!

[Greg in Maryland]

You don't say: Is the blade sharp? Is it clean? Is the rip fence in alignment?

These are the only suggestions I have. A properly tuned saw with a sharp blade should handle this job with no problem. It certainly sounds like an alignment or blade problem, not a load problem.

Warren

I have only had the saw for a short time (<3 months) and have not used the saw too much. I would think that the blades are still sharp.

Before I started, I verified alignment of the fence to the table, but not to the blade. I'll go back and recheck that part.

Thanks for the info.

Greg

[TheRic]

Not 100% sure, so I'll ask. The saw and vac are on two separate lines?!! If not there is your problem. IF two separate lines, hmmmm.

[Greg in Maryland]

Oh, and one more thing. In the future, when this sort of thing happens, STOP! Your saw is telling you something. Burning wood enough to set off smoke alarms and tripping circuit breakers is time to come here, ask questions, and research a little. SAFETY FIRST!

Point well taken.

[Greg in Maryland]

Not 100% sure, so I'll ask. The saw and vac are on two separate lines?!! If not there is your problem. IF two separate lines, hmmmm.

Saw and vacuum were on same 15 amp outlet.

[gjat]

My first guess is to say the blade had built up gunk and needed cleaning.
Burning smell.
Laboring during cut.

It only takes a bit of built up gunk to cause the blade to heat up, attracting and building up more gunk, making the blade heat up more....

Combine the two tools on the small circuit robbing power...

[maxparot]

After checking your alignment and cleaning the pitch off the blade.
I'd wonder about the moisture content of the maple. If it isn't well dried out it could cause a quick pitch build up and cause your problems.

[gary]

Warren

I have only had the saw for a short time (<3 months) and have not used the saw too much. I would think that the blades are still sharp.

Before I started, I verified alignment of the fence to the table, but not to the blade. I'll go back and recheck that part.

Thanks for the info.

Greg

This is wrong (in bold). The fence should be aligned to the blade - the table is meaningless.

[Lonnie in Orlando]

I hate cutting Maple ...

Greg:

I hate cutting Maple. It just likes to burn. I ripped both hard Maple and soft Maple with my BT3000 over the last couple of months. A cabinet maker has been building cabinets on-site for our kitchen remodel for the last eight months. Both of us end up with burn marks in our cuts. Smoke has belched from the cuts more than once.

A few suggestions:
- Sharp, clean blade.
- I got better results from a Woodworker II with a "few miles" on it than I did with a new Freud rip blade. (I don't think much of the Freud rip blade.)
- Raise the blade higher. With the blade buried in the cut, the teeth are always in contact with the wood, creating more drag and heat. With the blade higher, the teeth only contact at the infeed and outfeed side of the cut.
- If you can keep up the RPM's, experiment with the feed rate. Too slow will accelerate burning. Too fast will bog down the saw and/or produce a rough cut, but will burn less.
- Face joint the board to remove any twist.
- Watch for indications of internal stress that will cause it to pinch the blade.
- Rip wider than you need, then joint or sand to final width.
- I didn't have much success cleaning up a cut with a "half-blade-thickness" final cut.

I got a lot of (what I suppose was) harmonic flutter from the blade. Caused the teeth to gouge the edge of the cut. Never could find a solution to the problem.

I agree that the Shop Vac and table saw on the same circuit probably pulls too much current.

Good luck,

- Lonnie

[TheRic]

Quick fix / test. Run an extension cord from another outlet to run the shopvac (forget about the sears switch for this test). Make sure that extension cord is heavy enough. Cut one piece, see if you see a major improvement. If major improvement, electric drop was problem. If only a minor improvement then you have something else also causing a problem.

The saw should be on it OWN circuit NOTHING else!!

[LCHIEN]

There are a number of things and you may wish to read the BT3 FAQ linked at the bottom of my Sig line, bottom of post.

BUt I will tell you right away you are doing one bad thing. The Shop vac/autoswitch thing will work fine for light cutting but is a problem under heavy loads.

You have a 15A line. The sho vac draws anywhere from 5-15 amps depending upon its size anytime it runs (thats the way blowing/sucking type air moving motors work) in an open duct mode, lets assume 10A. That leaves just 5A for your saw to work. The saw motor draws some current as it spinns and then draws more current the harder its asked to work. Your saw is rated to draw 15A if it can to do the hardest work.

In your case you asked it to do more work and it could not find the power and slowed down to where it burned or it tripped the circuiot breaker when it tried to get more than 5A.

The way table saws are supposed to work:
You feed the wood quickly enough so that it spends little time being rubbed on the side by the blade. If you feed too slow then the repeated friction on the same point of the wood will burn the sides.

If the motor removes material fast enough then you can feed fast enough to prevent burning. If the motor does not remove material fast enough, then you feel like you are forcing the wood when you try and push, and it burns.

An underpowered saw will burn wood. An adequately powered saw will cut fast and allow fast feeding so that it doesn't burn. Thicker woods, harder woods, and bigger kerfs and fast feed rates always require more power, in your case only the feed rate was left in your control given the hard, thick wood so it burned and felt like it labored.

First thing you must do is give the saw free access to 15 Amps, that means ditch the autoswitch, run the vac off another circuit (breaker, not just outlet). This willmake the biggest difference.

After that, you can do a few things to help further:
Given that you must cut this piece of wood, (e.g. can't control hardness and thickness) and you are already using a thin kerf blade,
1) make sure the blade is sharp.
2) get a ripping blade (24 tooth, 10" blade that says its good for ripping) this will cut more aggressively (faster) and clear cuttings faster for rip cuts (and it really does).
3) make sure that all the fence is in alignment and some say that having the fence kicked away from the blade .003-.004" at the rear of the blade will reduce the tendency to burn by keeping the wood not pressed tightly to the blade.
4) Use no extension cords or if you must, use short (10 ft or less) 12 ga. cords. This will prevent voltage loss which is as damaging or more than being current limited.

And then last but not least, some woods are very prone to burning. Maple is one of the worst.

[Lonnie in Orlando]

Greg:

I read your post again - guess I missed the thickness of the cut the first time. Increase the number of passes to three or four to make the cut in stock that thick. For only a 10 inch cut, five passes won't take much longer, but will lower the chance of overloading the saw or burning the cut. The universal motor in the BT3K can't chop through 1-3/4" hard Maple in one pass. The suggestions in my previous post still apply.

- Lonnie