cutting birch plywood/tripping breaker

[rdewinter]

While making several cuts of birch plywood making cabinent sides and shelves, I noticed my blade getting dull and eventually burning the wood. I used a new 80 tooth ss plywood blade. At one point the saw stalled and tripped the breaker and another time the blade wobbled (checked everything and blade, arbor and set screw were tight and all locks including quill were locked). Removed the blade and noticed the teeth were brown and slightly gummed up. This leads to several questions.
1) is the ss steel blade a good one? Suggestions please for another brand.
2) is the blade salvageable by cleaning up with oven cleaner?
3) is the saw stalling problem a dull blade or a problem with the headstock? or both?
4) is there such a thing as a carbide tipped 80 tooth sawblade?
5) is there inherently a problem in cutting plywood?
Thank you for your input.

[scottss]

I have been cutting oak and baltic birch birch and solid oak and elm for a year with the same blade. Its a porter cable varible tooth razor. http://www.portercable.com/index.asp?e=3399&p=5102
I have cut hundreds of board feet with it and it cuts what ever I run through it. Clean cuts with plywood also.

[paul heller]

I found that spraying the blade with a lubricant (they make a special verison for table saw blades) made a big difference. It is dry coat formula that does not get on the wood.

Yes, you can (and should) clean your blade. You can even get it sharpened. But if it is warped, throw it out.

Make sure the fence alignemnt is as close to perfect as you can get it.

I did all these, fed the wood slowly, and my breaker tripped a lot less. But it still would occasionally trip. I finally ran a 20 amp line to my shop. No breaker trips any more.

Paul

[Ed in Tampa]

While making several cuts of birch plywood making cabinent sides and shelves, I noticed my blade getting dull and eventually burning the wood. I used a new 80 tooth ss plywood blade. At one point the saw stalled and tripped the breaker and another time the blade wobbled (checked everything and blade, arbor and set screw were tight and all locks including quill were locked). Removed the blade and noticed the teeth were brown and slightly gummed up. This leads to several questions.
1) is the ss steel blade a good one? Suggestions please for another brand.
2) is the blade salvageable by cleaning up with oven cleaner?
3) is the saw stalling problem a dull blade or a problem with the headstock? or both?
4) is there such a thing as a carbide tipped 80 tooth sawblade?
5) is there inherently a problem in cutting plywood?
Thank you for your input.

RDEWinter
What you described is the classic results of
1. either the fence is not parallel to the blade or
2. your twisting the wood as you pushing it through the blade.

If the blade now wobbles you have heated it up to the point that it is now warped. Toss it!!!!!!!!

Check you fence and insure it is exactly parallel to a new blade then feed the wood so the wood stays in complete contact with the fence.

Your blade was probably fine (shot now) as is your SS you need to buy another blade a SS 80 tooth should work fine and begin again making sure you feed straight.
Which is nearly impossible to control with a full sheet of ply. The tiniest movement 8ft out and 4 ft over really twists the wood causing binding, smoking, warping and circuit breakers tripping.

Many people cut Ply and other sheet goods over size with a circular saw then they cut to the the exact size on their table saw with the more manageable pieces to prevent trying to man handle a 8x4 sheet of ply that is nearly impossible to feed straight.

If your doing a lot of sheet good work you may want to consider a guided tool system such as EZ guide or Festool. With these you use a guide rail, dust collection and "chip out preventing" fixture on a circular saw to produce cuts that are near perfect and can be cut once exactly to size.
Ed

[8iowa]

I used to cut a lot of 4x8 sheets on my shopsmith.

You could be encountering mechanical problems such as a dull blade. If you are not using the saw guard with it's riving knife, the kerf could be closing behind the blade and "pinching" it. Not having the blade parallel to the fence will also create serious problems on a long cut.

On my original Shopsmith 500 the fence was rather short for long 4x8 sheets so I made an auxillary 5' long fence out of 3/4 plywood that bolted to the Shopsmith 500 fence with two 1/4 x 20 carriage bolts and wing nuts. I still have this auxillary fence but when I upgrated to 520, I no longer needed it.

I also found that cutting large sheets was a much smoother operation with someone to assist me on the outfeed side. I could handle 1/4 or 3/8 sheets by myself, but I always got into trouble binding the saw blade when trying to cut heavy 3/4 sheets by myself. Those dog-goned rolling stands always seemed to fall over at just the wrong time.

You might also try reducing the speed down to around "M". This will greatly increase the cutting torque, and eliminate burn. I have a 10 inch Shopsmith plywood blade but experience has shown me that the carbide combination blade works very well.

You might also be experiencing electrical problems. Most garages have at best two 15 amp circuits. This is marginal for a fully loaded Shopsmith, especially if there are other things on the circuit such as lights and small appliances. If this is your situation, one of the best things you can do is to add a 20 amp breaker to your panel and run a #12 gauge line to a 20 amp recepticle, and let this be a dedicated line for your Shopsmith.

[rdewinter]

Thanks guys, good advise. I appreciate the help.
Larger sheets of ply are very difficult to feed properly. Will return to my circular saw and clamp guide for cutting larger pieces of ply.
Regards
Bob

[8iowa]

Don't give up on the Shopsmith so soon. This is a great tool that has enough ripping capacity to trim 1/8 inch off the edge of a 4x8 sheet. You would spend well into four figures in order to get a cabinetmaker's saw that could do the same. Get a couple of ball bearing roller stands to support stock on the outfeed side and if necessary, use sandbags or other weights to make them hold their place more firmly. If cuting large sheets is going to be a frequent occurance you can also make an outfeed table with a slick plastic surface. Shopsmith offers both a support table and extension brackets. If you are still in the old 500 mode I would be glad to send you a sketch of my five foot auxillary fence, which is easy to make, and did a great job on long 8' cuts.

I too have cut large panels using a circular saw and long straight-edge. This is always a scary operation, requiring you to walk along the length of the cut, or reach further than you should, while trying to keep track of where the cord is, and trying to catch the piece that will fall away as you near the end of the cut. Sometimes it is necessary to also cut into your supporting sawhorses. Sooner or later something will go wrong. Rather than have sawdust all over my shop, my circular saw cutting was always done outdoors. This was not a lot of fun on a hot and humid Florida summer day. Someone who has no other choice but to cut plywood in this manner would love to have your Shopsmith.

[Ed in Tampa]

Don't give up on the Shopsmith so soon. This is a great tool that has enough ripping capacity to trim 1/8 inch off the edge of a 4x8 sheet. You would spend well into four figures in order to get a cabinetmaker's saw that could do the same. Get a couple of ball bearing roller stands to support stock on the outfeed side and if necessary, use sandbags or other weights to make them hold their place more firmly. If cuting large sheets is going to be a frequent occurance you can also make an outfeed table with a slick plastic surface. Shopsmith offers both a support table and extension brackets. If you are still in the old 500 mode I would be glad to send you a sketch of my five foot auxillary fence, which is easy to make, and did a great job on long 8' cuts.

I too have cut large panels using a circular saw and long straight-edge. This is always a scary operation, requiring you to walk along the length of the cut, or reach further than you should, while trying to keep track of where the cord is, and trying to catch the piece that will fall away as you near the end of the cut. Sometimes it is necessary to also cut into your supporting sawhorses. Sooner or later something will go wrong. Rather than have sawdust all over my shop, my circular saw cutting was always done outdoors. This was not a lot of fun on a hot and humid Florida summer day. Someone who has no other choice but to cut plywood in this manner would love to have your Shopsmith.

8iowa
I don't know about you but I'm not a as young as I use to be, and throwing a 4x8 sheet of ply around is not much fun anymore. 4x8 sheets of MDF is even worst.

I agree cutting with a guided saw system can be different but it is also a little easier if you do a few things. First some of the newer circular saws are coming out with dust collection capabilites. Hook a vac to the Porter Cable mag series and you will catch most of the dust. Make a few home made shields and hook the vac and you will catch nearly all of it (what you miss won't amount to a small handful).

Where to cut? Well most guys have discovered a 4/8 seet of insulation foam the stuff 2 inches thick set between saw horses allows you to cut ply without worry of cutting you horses, you cord or sticking you hands under to catch fall off. The foam can be used over and over and over again and if cut and taped to is folds makes storage fairly easy.

Also with some the formal guided saw systems they now have the saw set up for dust collection (99%) but zero clearance around the blade so there is absolutely no chip out. Plus the guide itself has a stick tape time that keeps the guide in place (no clamping necessary).

I know of two professional shops that got rid of slidding table saws and panel saws in favor of the new guided saw system. When done properly the wood doesn't have to be moved and the operator is actually safer. Big savings on insurance.
Also on one of the other forums a professional cabinet maker swears he has experienced a 30% increase in productivity since going to the guided saw system.

A solid material counter supplier here in Tampa has converted his operation to a guided Saw system. Today in his warehouse is a 12 radial arm, 12 inch sliding table saw and a panel saw that go basically unused now that they have the guided saw system. I watched him cut some solid material for an order and I don't think any saw could do it better or faster. Interestingly they slid the solid material to a foam covered table laid out the lengths and made the cut. I watched them glue the two pieces together and the fit was as if the ends had been jointed. And the real bonus was they were able to do it in the time it took to write this response.

I'm looking seriously at the the guided saw systems, I think they are the "PERFECT" complement to the Shopsmith.

Do some searches and see what others are saying about these systems. Even Tommy Silva and Norm used one to build book cases one episode on This Old House. A guided saw and router using the same rail cut ply into usable piece, then they used a router on the same rail to cut the shelf dados and finally they cut the taper on the filler board. From what I could see this was far quicker than sitting up a table saw cutting then switching to dado and making the cuta then switching back and cutting a taper.
Ed

[8iowa]

Ed:

You and I seem to get into conflict - which is not doing rdewinter any good.

I'll still stand by my original posting in which I said that the job goes much smoother with someone to help on the outfeed side. My wife and my daughter both have helped me to cut 4x8 sheets on our Shopsmith. Our favorite woodworking tool can do an excellent and accurate job on plywood up to 3/4 inch - and do it safely.

If God forbid I get "into the business" of cutting 4x8 sheets on a daily and regular basis then I might consider buying a panel saw, or going into an elaborate setup as you described. However, most home workshop projects seldom require cutting more than a few sheets of plywood.

Circular saws, like chain saws have bad safety records. Unless you use one a lot and gain a lot of familiarity with it's use it is wise to always be scared of the things and not stretch yourself into cuts with which you are uncomfortable. Frankly, I can't think of anything worse than having to keep track of both an electrical cord and a shop vac hose while trying to make a long cut along a rail.

[dusty]

I no longer cut sheet goods on the Shopsmith until they have been cut down to manageable size with the circular saw.

However, I do not mean to say that no one should cut sheet goods on the Shopsmith. I don't do it anymore because I can not handle a sheet of plywood or MDF, on the table saw safely.

When I was younger, stronger, more agile and less cautious, I did it all the time.

If I had a table surrounding my table saw, like Norm does, I might still do it. But I don't, therefore, the saw horses and the circular saw get a workout when I have sheet goods to cut.

Yes, cutting the extension cord with the circular saw is not wise either. No one said this was a danger free hobby.

No arguement intended here. Just a plea. Be careful, work SAFELY, come back to enjoy it another day.
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