Blade Wear Query

[Jim McDonald]

We all know that blades get dull from the friction of the wood fibers (fibres), minerals in the wood and heat.

The true question (and I'm being serious):
Do the blades age faster in hardwoods with a fast or slow saw speed?

I think I see both sides of this: At faster speeds we are removing wood faster, hence more heat, more contact with the nasties in the wood, etc., but it is not taking as many strokes to get from A to B. And, at slower speeds, we are not generating the heat, but it takes longer to cover the distance.

Any deep philosophical thoughts or even scientific fact out there on this?

[minowevie]

JIm, good quistion, I am still a slow poke. I can't seam to handal my blades going faster thank 1700 rpms. and thats to fast for small fretwork. I tend to go through more blades and burn wood when I go faster. so I stick to the slower speeds. maybe I am not moving my wood fast enouph or something, but when I go faster, I just have problems. 1300rpms is plenty fast for me. and the blades seam to last longer, and I get more work done. ??? just me don't know. but then stacking might be some of it. I don't stack much. maybe 1/2" sometimes, but like cutting one piece at a time. I just have more control that way. but then I don't sell eather, so the more exsperianced. who. big word, do a better job , becouse they have too , I guess. I like keeping it slow and simple. your friend Evie

[Pajaro]

I'm with you Evie. My EX-21 at full speed seems to melt #2 and smaller blades. After about 10 minutes the blade is crooked and bent when I release the tension. I run my saw just fast enough for it to blow the sawdust off the work, other wise I would have to take my respirator mask off every 2 minutes.

[Barefoot1]

The only time I have maxed the speed on my Hawk is when I am doing compound cutting. I prefer a much slower speed for far greater control when doing fretwork.

So on the the deep philosophical question. When you increase the speed I would think that you are still going to take X number of strokes to get from point A to point B whether you are at 500 or 2500 strokes per/min. The blades teeth will only cut so much wood per stroke. (There is a wood chuck joke here somewhere. ) So you will get there faster but you will generate more heat. So I would think that you will dull the blade faster due to the heat at a faster speed. I am also pretty sure your feed rate would play into this as well; as would the pressure you are applying. If you apply more pressure than needed to obtain the best rate of cut you will be generating more heat than if you were applying just enough pressure to let the blade cut at it's optimum rate. Visa Versa for not applying enough pressure or to slow of a feed rate as your blade would not be getting an optimum depth of cut, thereby taking longer to get through the cut and therefore generating more heat. And just to throw one more monkey into the zoo, wood thickness and hardness would also have an effect but those being equal I would put my money on increased speed having the more detrimental effect on blade sharpness. But hey, I am just guessing since I left my scientific calculator in the shop . . .

[Fremmed]

I don't know what the best choice is. I tend to run very slow on delicate cuts, 2/3 speed (that's the technical term <g>) for most others. I do tend to find that the thicker wood does cause more burning on the blade (however, sometimes the blade turns such a wonderful shade of blue, I just smile <G>).
Bottom line is I try to run as fast as I can based on the conditions. Kinda like driving a car eh?

[Plaquerd]

I cut at full speed on 90% of my work. Thick wood, thin wood, fret work or making boxes or compound cutting or what ever I 'm cutting. Don't burn blades or break blades. They don't dull any faster or bend or turn blue. I do slow down when doing some of my inlay work, when using a 2/0 blade in harder woods.

[Rolf]

Heat is the enemy, too much and it will take the temper out of the blade and wear rapidly. I must say I don't really worry about blade life. I cut at a speed that is comfortable for the project that I am working on. I rarely change my speed. When I feel that I am pushing too hard or it is harder to control dirrection or I see wisps of smoke I toss the blade.
Depending on the wood that could be 10 min or 30 minutes of actual cutting time. If it is a critical project or very detailed I always start with a fres blade.

[Marsha]

I don't worry too much about speed, I generally run my saw at full speed. I do turn it down a notch when cutting thick hardwoods. I rarely break or burn a blade, and like Rolf, I know the blade needs to be changed when I start pushing the wood when the blade is not cutting as easy. I start every new project with a new blade, but I do use the old blade for rough cutting. When I see that little puff of smoke that tells me the blade is heating up, I usually stop and wrap my project in clear packing tape, this cuts down on the burning of the wood, but I don't know if it cuts down on blade wear.
Awhile ago my friend and I were discussing woodworking and he said he never uses anything but pine because he dosen't have good enough tools to use hardwoods. I spoke to some of the guys on a woodworking site about that statement and I was told that soft woods such as pine are the worst woods on blades and router bits. There is so much sap in pine that it gums up the blades and dulls them very quickly, this is probably also true with scroll saw blades.
Marsha

[sawdustus]

My basic rules are:

Thick wood, faster speed; thin wood slower speed.
Hard wood, faster speed; soft wood, slower speed.
Plywood, change blades frequently.

Since I do a lot of stacked, up to 1/2" thick stacks, using thin plywood cutting, 1/4" to 1/32" I find that the glues in plywood heat up a blade much faster than even mahogany, oak or cherry, so I am changing blades more frequently. I may also be my technique: I tend to put a lot of tension on the blade and to push harder than I have too.

sawdustus

[marshall]

You know that its good that they sell the blades by the gross, for it seems that I do go though a lot of blades also. Al-well as long as we are making those pretty things for the family, friends, and just whoever. You know I hardly ever just pay attention to really what speed I keep it on, maybe its just me , and I don"t know what the most comfortable speed is. Just whatever feels the bests at the time, guess it something that you pay no mind too after so long ,I know some of us are a little strange> all well !!! Marshall