horizontal bandsaw doing a slow hip-hop

[black85vette]

Plunk your magic twanger

Marv; I think there were a number of people who missed that reference. :big:

 

[zeeprogrammer]

Plunk your magic twanger before dismounting the old blade.

Rof}

I did miss that. But it's better if you quote the whole thing.

Good one. Bunch of old....

 

[retrodyne]

Hi Ho Zeeprogram

Here is a tip that might help installing a new blade. Get at least 2 cheap metal spring clamps, fairly strong. Woodworkers use them for holding flat wood while gluing. With saw standing up install blade in the guides first then rotate or push blade back and surrounding the pulleys. I usually put both clamps on the bottom or drive pulley to hold the blade where it belongs. Now your hands are free to install on the top pulley and adjust enough tension to keep it there while you check everything before removing the clamps.

Good luck

Retrodyne

 

[zeeprogrammer]

Thanks retrodyne and welcome to the forum.

Hit the Welcome thread and tell us about yourself.

If you've been reading the forum you already know we like pics and videos. If you just started...well...we like pics and videos!

 

[zeeprogrammer]

Oops. Just found out where the phrase 'Plunk your magic twanger' came from. Just a little before my time. I do remember Andy Devine though.

 

[Kermit]

Glad I could help then.

 

[zeeprogrammer]

Glad you said something kermit. I had missed your post. The tension tip is helpful.

I wouldn't be surprised if my bandsaw has the same quirks...if I remember right, we have the same one.

Maybe a silly question...do you turn on the saw and then bring it down to cut or do you bring it down and then turn it on? I suspect the answer is not what I've been doing. ;D

Thanks.

 

[Kermit]

I've had lots of luck with turning it on first and letting it go around a bit, before putting it to the metal. SO much luck in fact, that I've never even tried it the other way.


Mine does the sine wave wiggle as well when I saw something. It is due to the weld, but has a few more smaller wiggles that are just oscillations of the one the weld spot sets up. The weld passes the cut and the saw jumps a bit, then jumps a little smaller with each bounce till the weld comes back around and starts it off with a big bounce again. Perhaps mine is not as "jumpy" as yours is, but it depends on the blade I use as to how much the bandsaw bucks. Gotta be those welds. Some blades are cheap ones and if I checked I bet it is those that are the 'bumpier' of the bunch.

But the rickety little baby will make an amazingly straight cut, so I'm leaving well enough alone for now...


Kermit

 

[zeeprogrammer]

Well now I can tell you NOT to try it the other way ;D.

Kinda stupid now that I think about it. Probably broke one or more teeth every time I started the thing.

I don't think the weld had anything to do with it...the hop seems a lot slower than the rate of rotation...besides...it started rather suddenly.

Thanks kermit.

 

[rake60]

The manufactures manual does make a few suggestions.

Rick

 

[zeeprogrammer]

My manual doesn't have that chart. That'll be useful...thanks.

It also didn't have as clear instructions. It was 'somewhat' buried. Step 9 in fact.

Still...I apparently need to change my glasses and read the manual thoroughly. ;D

I was rereading and came across a one-liner that said a too slow speed can cause teeth to break. I'm thinking that also contributed. Things were fine until I cut a somewhat large piece of aluminum that seemed to take forever. It was after that that I noticed the problem. Checking further, I believe the speed was too low for aluminum.

Thanks Rick.

 

[zeeprogrammer]

I could start a new thread or open an old wound...
I've made my choice...

Against everyone's advice...I bought a cheapo blade. Not having replaced a blade before, I figured I had a pretty good chance of damaging it. So I decided I'd learn on this one and then switch to something better.

Now...at the risk of the answer being..."You dolt! It's the cheapo blade"....

Backing up just bit...
I had busted some teeth due to incorrect usage in applying the blade and the wrong speed. This gave a slow hip-hop action to the system as the blade bounced off the material. Shortly thereafter, the blade snapped.

Today I went about replacing the blade. Here's my observations and what happened...(nothing bad...but I have questions)...

I couldn't believe the amount of aluminum crud all over...so I spent some time cleaning everything out and figuring out what's what. Instructions mentioned some parts by number...but the illustration didn't contain them.

I checked the clearance between the blade guide bearings...supposed to be less than .001" clearance between them and the blade. I used shims to check that. The gap was slightly bigger. However, instructions talked about using a hex key to loosen the nuts to make adjustment. Hm....no hole for a hex key. And I couldn't see how I could adjust the bearings closer. So I didn't do anything (for now).

I suspect I just have to loosen the nut with a wrench...put sufficient shims between the bearings, squeeze them together, and then tighten it up again. Is that right?

I was surprised by how the blade gets twisted as it comes off the drive wheel, through the bearings, and onto the idler. I can see now why Marv suggested using twist ties. Sheesh that was fun.

Got things tightened up and 'twanged'.

Then it was time to check blade tracking. I was surprised it was so far off. Is that unusual? I followed the instructions and adjusted the screw until I saw the blade track the idler 'properly'. However, I noticed the blade was a little further out on the drive wheel. I don't see any way to adjust it better. While adjusting the blade I could hear a light click every few seconds. I think it was the weld going by. Changing the tracking made it come and go. Is that unusual?

As I said...cheapo blade...the weld spot seems weak. It looks like you could bend it back and forth two or three times and it might snap. When I unwound it I discovered the teeth were facing the wrong direction. It took me a while to realize what happened and that I needed to twist it inside/out. Luckily I had discovered the weld issue. I put the blade in a vise (with the weld in the jaws), and twisted the blade inside/out. That went very well and I have to admit I was bit proud of myself. ;D

Now for the part I'm unhappy with. I set it up to cut a bar of 12L14. Although it cut very well and much more quickly than I had expected, the blade pops up every 2 and half seconds or so. (I was running at 200. It's a 64" blade.) And, when it comes down...I get a little bit of smoke from the cutting oil as the blade grabs.

So that's the part I don't understand...and the part that's (I hoping) is most likely...the cheapo blade...maybe the weld.

Any thoughts...good or bad...are welcome.

Thanks. Sorry it's a long post.

 

[Cedge]

Carl
It's not unusual for cheapo blades to have some amount of mismatch at the weld point. That will give you the hopscotch thing you've got going on. The blade will cut great... for a little while, then it goes down hill pretty rapidly. The jumping will eventually weaken the blade at the weld and it will fail due to the beating it's taking.

Bimetal... variable tooth.... gotta trust me......LOL

Steve

 

[black85vette]

Repeat after Steve over and over again.....

Bimetal... variable tooth, Bimetal... variable tooth, Bimetal... variable tooth.

 

[black85vette]

BTW; first time I bought a new blade and went to put it on, it uncoiled "inside-out". I cussed and spit and fumed about those idiots selling me a blade that ran the wrong direction. Finally figured it out and calmed down, but it did mess with me for a bit. :big:

 

[zeeprogrammer]

Thanks guys.
Actually pretty happy. Learned quite a lot about the bandsaw. The cheapo blade was small insurance to get that learning without ruining a more expensive blade.

black85vette...yeah...that was my first thought too..."What? I got the wrong one?"

For other people like me (and I know you're out there as I happen to be at the bottom of the heap)...

Wear gloves and glasses.
It comes folded up and tied. Be real careful when removing the ties. The thing will spring on you.

 

[vlmarshall]

Be careful with the OLD blade too. Dull, or broken, it'll bite.

When I'm changing blades, I'll usually fold the old blade and break it in a few places so it's not such a springy monster, waiting to jump out of the trash and grab someone.

 

[Deanofid]

I'll second Vernon's advice about breaking up that old blade, but save some short pieces. You never know when you will need a short piece of really thin tool steel.

Dean

 

[zeeprogrammer]

Excellent advice Vernon and Dean.
Thanks very much. I'll be sure to do that.

 

[ksouers]

zee,
I have the same bandsaw.
This may seem a little odd, but how much weight is being applied by the blade to the work? I don't expect a number.
At the back of the saw is a handle that looks like one side of a bicycle handlebar and grip. It's connect to a spring through a piece of all-thread and a hook or loop. Turning that grip will change the weight that bears down on the piece being cut. If it's too light the saw could bounce.

Might want to try adjusting that spring to see how it cuts.