A bandsaw lesson that cost me $25

[Lars S.]

I just learned an interesting lesson about bandsaws and what can happen when the blade binds.

I obtained about 20 feet of 10"x10" pine beams from a rennovation site (100 years old beams with very tight growth rings). I had the beam cut into 4 foot sections and then proceeded to resaw them into more manageable planks 2-3" thick. Anyway, as I was cutting through the second one, the blade bound up. I waited a few seconds, turned off the saw; readjusted the beam; turned on the saw, etc., I repeated this process about four times and only then decided that I needed to drive some wedges into the kerf to open the kerf up. So I did this, turned on the saw; waited a second; when the blade remained frozen I turned off the saw, wedged the kerf more; and repeated. After about the fifth try wedging the kerf open, my saw was free and I managed to cut the rest of the beam. Unfortunately, the tracking on the saw was now terrible and the blade didn't cut well at all.

It turns out that while the blade didn't move, the 2HP motor and belt did, and the wheels spun free under the blade. I probably would have heard something except for the fact that I had hearing protection on at the time. It also turns out the melting point of urethane tires is somewhat lower than the the heat you can generate from rubbing urethane against steel at several thousand RPMs. My tires melted. Lesson learned. I don't recall this lesson in "The Bandsaw Book," but perhaps it was too obvious to print.

At least Rockler has free shipping for the month of March so I was able to get a new set of tires ordered and shipped for about $25.

[SwampBug]

out of curiosity, did you try holding down the beam and hand rotating = the blade backwards?

--=20 SwampBug

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I obtained about 20 feet of 10"x10" pine beams from a rennovation site=20 (100 years old beams with very tight growth rings). I had the beam cut=20 into 4 foot sections and then proceeded to resaw them into more=20 manageable planks 2-3" thick. Anyway, as I was cutting through the=20 second one, the blade bound up. I waited a few seconds, turned off=20 the saw; readjusted the beam; turned on the saw, etc., I repeated this=20 process about four times and only then decided that I needed to drive=20 some wedges into the kerf to open the kerf up. So I did this, turned=20 on the saw; waited a second; when the blade remained frozen I turned=20 off the saw, wedged the kerf more; and repeated. After about the fifth=20 try wedging the kerf open, my saw was free and I managed to cut the=20 rest of the beam. Unfortunately, the tracking on the saw was now=20 terrible and the blade didn't cut well at all.

It turns out that while the blade didn't move, the 2HP motor and belt=20 did, and the wheels spun free under the blade. I probably would have=20 heard something except for the fact that I had hearing protection on at=20 the time. It also turns out the melting point of urethane tires is=20 somewhat lower than the the heat you can generate from rubbing urethane=20 against steel at several thousand RPMs. My tires melted. Lesson=20 learned. I don't recall this lesson in "The Bandsaw Book," but perhaps=20 it was too obvious to print.

At least Rockler has free shipping for the month of March so I was able=20 to get a new set of tires ordered and shipped for about $25.

[Phisherman]

[Phisherman]

backwards?

I'd be interested in knowing this too (my experiences is turning the wheel backwards helped very little). Using wedges (and patience) will help. With a resaw operation, a binding blade is classic especially with a large chunk of wood.

[Lars S.]

I did the first time with no luck -- this is a massive 10" pine beam and the blade was firmly pinched like a 10" wooden bench vise. If I had kept opening the cover to try spinning the wheel backwards, of course, I would have noticed the tires melting. In the future, it will always be part of my routine when the blade binds.

L

[SwampBug]

I have never personally encountered the problem or my "thing to try" but = it was the first thing that come to mind.

--=20 SwampBug

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I did the first time with no luck -- this is a massive 10" pine beam=20 and the blade was firmly pinched like a 10" wooden bench vise. If I=20 had kept opening the cover to try spinning the wheel backwards, of=20 course, I would have noticed the tires melting. In the future, it will=20 always be part of my routine when the blade binds.

L

[loutent]

Never ran into this, but thanks for the heads up Lars!

Most always with hearing protection in the shop.

Lou

[GerryG]

[George]

Makes much less difference than the position of the heart in the beams in question, and the moisture content of the center versus the outside. Both can cause the kerf to close, _regardless_ the blade. Also very important to have a flat surface down so the piece won't roll and bind.

The real lesson is to keep a few of those shingles or shims available as wedges and use them. Also watch what's happening with the cut while doing such pieces.

[Lars S.]

In my case, I was using a 1/2" wood slicer (I forget the teeth layout, but I think it's 3tpi). The problem, as only now I can fully appreciate, is that I was sawing down the middle of the heart and (possibly) the beams had taken on some rain on the outside. The blade completely locked up like a 10" bench vise. It took two metal chisels to get the kerf open enough to tap in the wooden wedges.

Now I have a dozen wedges of various sizes and a few thick metal chisels at my disposal. When I get my new urethane tires, I'll give resawing another try.

Lars

[mac davis]

I'm new to bandsaws, so I took a tip from my lathe experience and have fairly low tension on the belt... my theory being that I'd rather have the belt slip than the blade, (blade slipping on the tires), or the blade kinking and screwing up the tires and/or guides (BTDT)

mac

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[mac davis]

Lars..

Just 2 cents from a newbie, but for resawing 10x10" hardwood, (which could be a gloat in itself, so you suck ), I'd want the biggest blade that your saw can use... usually a 3/4" 3TPI..

I buy my blades at a local saw shop that welds them up when you come in, and I tell them what I want the blade for... for resawing, they made a couple of 3/4" with 3 tpi and (I probably have this wrong) something about little of no tooth set and no raker teeth??

They seem to be very good blades and were about $15 each..

mac

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[Lars S.]

I was thinking of using 3/4", but somewhere I read that such wide blades would wear out quickly on a 14" bandsaw because the turning radius is too tight. That is why I settled for 1/2".

Have you had good exerpiences with your 3/4" blades on a 14" saw? Or is your saw a bit larger?

Lars

[Lars S.]

This sounds like a good idea. I'll check the belt tension when I replace the tires and possibly reduce it a bit. Now that I think about it, I suppose that it is possible I put too much tension on the belt in the first place. Time to blow the saw dust off the manual and take a look.

Lars

[mac davis]

nope, 14" Ridgid with the riser kit..

I guess it depends on what you're cutting and how often you change blades..

My manual says that a 3/4" blade will cut a 7" dia. circle, a 1/2" about a 5"... seems pretty accurate so far...

Most of my info is from the wRECk, but my feeling is that for resawing and most straight stuff, you want the widest, TPI blade that you can mount, unless you're cutting fine slices, in which case you want a 3/4" blade with no set and more TPI, for a smooth cut...

OTOH, if you're doing a lot of smaller curves or scroll work, you'd change to a

1/4" or 3/8" blade with a lot of TPI...

I hate blade changes since I added a shop built table to the saw, so I keep a

5/8" 4 TPI blade on most of the time.. does ok for the limited slicing I do, stands up to cutting 7 or 8" thick green blanks, and gives me a good tight curve for rounding bowl blanks.. YMMV

mac

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[L. Peter Stacey]

Looking at this problem from a different view Lars. It is important to be aware that ALL drive belts, whether bandsaw or vee belts are designed to transmit drive, ideally with minimum or no slip! Where there is slip there is friction and heat which leads to inevitable failure. Just like the weakest link in a chain, whether it is the vee belt, aluminium pulley or bandsaw tire. Even a car clutch which is designed to slip while it gradually takes up the drive/ load, it too will wear out prematurely, if it is slipped excessively. If your bandsaw blade slipped on the tyres, then it either had too much load and excessive power to stall the motor, or there was insufficient drive to the blade which allowed it to slip in the first place. Whilst I am in agreement to reduce all areas of industrial harm such as dust, loud noises etc. One does need to be able to hear machinery running, in order to hear any changes that can indicate a problem is occurring. It is potentially dangerous to insulate ourselves totally from the tools we use, not only for the machines sake, but also for our own safety. Cheers from 'Down Under'

******************************** ,-._|\ Peter Stacey / Oz \ Melbourne Australia \_,--.x/ [e-mail] v

"Lars S." wrote in message news:2005032311384375249%lars@gsblasuchicagoedu...

said:

wrote:

[Edwin Pawlowski]

I've had a few people tell me the best re-saw blade for a 14" is 1/2" That comes from even people that make/sell blades like Suffolk Machine. You also don't want too many teeth so the cut material can be carried away more easily. I use a 3 TPI

[no(SPAM)vasys]

While the widest blade possible is ideal for rewasing other factors related to the particular saw come into play along with the blade width. The saw's frame must have the ablitiy to hold the tension on the blade while under load of resawing and the motor must have sufficient power to overcome the blade drag of the wider blades. For most 14" bandsaws a

1/2" blade is recommended because of these limitations.

[George]

They make a lovely 3/4 as well, specifically for the 14" set. 3AS-S at .025 thickness, raker set. Does a good resaw.

scroll down to AS-S

[mac davis]

Peter.. I almost learned that "sound lesson" last night...

The band saw is close to the DC and with all the noise of the DC, I almost stuck my hand into the blade, thinking it was off.. Luckily, My fear factor has made me develop a habit of patting the switch to make sure that it's off.. It's one of those things like looking at your watch.. I didn't even realize that I do it, until I touched it and found it on..

mac

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