Not only do I hate cutting bowed boards on my sliding compound or my radial arm saw, it is inherently DANGEROUS. Many woodworkers have been severly injured by not paying attention and having saws recoil or kickback. One of the reasons for this is that the teeth angle on some cut off blades is at a more acute angle, such as
The first issue to look at is the type of blade you are using. If it is not a 60 to 80 tooth blade, preferably with anti kick back teeth, you may want to start considering exactly what you need in a cross cut blade. Note: normally you can only get anti kick back teeth in a 60 tooth version, with 80 teeth there simly isn't the room to include anti kick back teeth.
A cross cut blade for a table saw if FAR DIFFERENT than it is for a sliding mitre or radial arm saw. One of the biggest differences is the hook angle on the teeth. On a table saw a hook angle of 10 - 18 degrees is fine because the blade is cutting the wood against the firmness of the tables saw's table. On a radial arm or sliding mitre it is quite a different story.
When you are cross cutting with radial arm saw or a sliding mitre the hook angle make a BIG difference with regard to the safety of the user. In the case of a radial arm or sliding mitre, or even a chop saw the hook angle should be no greater that 5 degrees and even having a negative hook angle is preferable. The problem with a 10 degree or greater hook angle when using on a radial arm or sliding mitre is that when the blade "grabs" the wood, it has a huge tendancy to want to lurch back toward the operator, which as you can imagine starts to create safety issues. Now the same tendancy can happen with lower angle hook, but to a much lesser degree.
What often happens when cutting these boards they get pinched in by the saw blade part way through the cut which then sometimes even stalls the saw and it must turned off quickly. This is not a safe situation. Another thing that happens sometimes is that part of the board "springs off" like it has a mind of it's own. Almost every board needs to be re-cut as there always seems to be some sort of misalignment thing that happens.
When you are dealing with boards that are cuped, twisted or warped, that alone should be an indicator to the woodworker that their are probably some stress in the wood that will make it want "grab" the blade part way through the cut.
I know what many of you may be thinking, "No Problems, if the blade is grabbed by the wood I can just hold the saw back from coming at me" .. HA .. you think ! ... Even a small 1/2 or 3/4 horse motor cutting through a board can create some nasty pull backs and this is where many woodworkers have run into to trouble!!!
There are a couple of ways to deal with cutting through these kinds of boards. If you have a radial arm saw, it is easy to rasie the saw and just cut a small path in the top of the board about 1/4 inch deep ... then progressively deeper cuts until all the way through the board. Another alternative for either radial or sliding mitre is SLOWLY cut the board by going in only a inch or two at a time, then re cutting and re-cutting. What this does is allows the board, if it is going to "pinch" the wood, it allows the slot where the blade is passing through to make this passage way slightly larger if there is a tendancy for the wood to moving inward or pinching the blade.
What ever you do, work safely and part of that means, working with the proper guides, ear and eye protection and the proper tools AND BLADES
Copyright - Colin Knecht