Has anyone ever had their bandsaw tire come off during use?
I have a MiniMax 16″ that’s about three years old. In doing some research, I learned that my saw turns at 950 fpm. I also know that bigger/commercial saw turn somewhere between 1800 and 2400 fpm.
So, by doing some calculating and increasing the motor pulley size, I was able to increase my saw to roughly 1800 fpm. But now that the wheel is spinning much faster, the tire is expanding and coming off.
My saw has a grove in the wheel for the tire to slip into, but it isn’t glued to the wheel. Does gluing it down sound like it will solve my problems?
Thanks
Jody Compton
Replies
Jody,
Try it, it will either work or it won't.
By effectively doubling the speed for which your saw was designed to operate at, is this the only problem? No increase in vibration or anything else noticeable?
Chris.
I've run the saw several times now(just for a few seconds) and the tires expanding off the wheels is the only problem. There is no additional noise or vibrations.
I just want to learn how to keep the tires on the wheels to see if it will cut well.
Any ideas out there?
Forget band-saws for a second. What would happen to the handling of your car if you were able to get 200MPH without changing any of the suspension. Your car would be very skitterish and unstable at that speed. When you change one item, you must change other items to be able to 'use' your first change properly.Think of the tires as huge rubber bands. The faster you spin them, the more they will stretch. The tires you have were NOT built for the faster speed and higher centrifical force. They have to be made of a DIFFERENT formula of poly to be able to stand the higher rpm. If you insist on a higher fpm, try sonmething in the 1200 - 1300 fps range, basically a 50% increase, NOT a 100% increase.
SawdustSteve
Hi Jody... It seems to me that if MiniMax set the saw to turn at 950 fpm and you basically doubled that speed, you're lucky that the tire comming off was your only problem. Yes, the factory can easily change pulley sizes to get greater fpm but didn't! There must be a reason for the 'factory' speed. I don't know if the bearings will have a shorter lifespan under your new set-up. Centrifical force is quite strong, and I don't know if the tires can take that sort of load. I wouldn't want to be around when the tire 'blows' off the wheel and jams the blade against the metal housing or if the tire expands enough to 'double up' under the (rapidly) moving blade and puts enough strain on the wheel shaft(s) to bend something.
And YES... I've had a tire come off a 14" bandsaw while I was using it. Lots of noise... damaged blade... lots of smoke from rubber tire rubbing against the upper housing.
Yes, there are some things you CAN play with and modify, but this one could be dangerous.
SawdustSteve
Edited 8/8/2007 9:15 pm ET by SawdustSteve
Thanks for your input. You are correct in what you say about several things.
However, I did talk to MiniMax about sawing faster with my current saw. They said the 16" saw was just as strong as their 18" (which cuts at 1800 fpm) but the fly wheels on the 16" weren't as heavy as the 18", and the added weight is what help the saw cut better. They also added a larger motor.
But, having said that, what keeps the tires on the wheels of the 18", or on any saw that is turning greater than 1800 fpm?
By doubling the speed of your blade, you are also putting twice the load on the motor and bearings. Chances are the manufacturer chose 950 fpm for a reason. If that machine could work well at higher speed, I imagine the manufacturer would have set it up that way and advertised that higher speed as a feature.
Thanks Bruce for you reply.
While talking to MiniMax I asked the same question, why doesn't this saw cut faster? Their reply to me was, "that's why we sell the 18" saw. Mr Compton, you need to BUY a new saw".
Your thoughts Bruce?
I had the upper wheel tire peal off the wheel on my ancient (pre WWII) Delta, but that was because the tire was cracked and dry. I replaced it, and later changed pulleys to get the speed up to approx the current standard. I've had no ill effects, and neither has the saw. Is 950 F/M the current norm for your saw, or has it been increased by the factory?
As some are want to say, "There ain't no free lunch."
The 16" is set to run at 950 fpm and MiniMax's 18" runs at 1800 fpm. And according to the MiniMax rep is the 18's wheels are heavier, and they added a larger motor.
If you look around - most bandsaws run between 2500 - 3500 fpm for cutting wood. And even on the slower setting - most of those saws still cut around 1700 - 1900 fpm. Sounds like your saw might have been set up for something specific. It might also have been slowed down because of your motor's power (or lack of).As for the tire coming off - I've seen some come off because of over tensioning and over loading the saws capacity. That mixed with an old worn, lose tire can lead to it wondering off. A replacement tire should fit really snug on the wheel ( really snug ) so that there is no way its coming off no matter what speed. If you've ever kept the door open on a bandsaw to watch it track - you'll see the wheels aren't really spining that fast ( all things considered. And the only that would limit your speed is the balance of your wheels and the bearings - and being that its a Mini Max - that shouldn't be a problem.Brian
Edited 8/8/2007 10:07 pm ET by Grey Clover Furniture
I agree with you Brian.
It shouldn't be problem for this MiniMax saw to run at 1800 fpm, it is an extremely well built saw, that's why I bought it.
Morning C3..
It shouldn't be problem for this MiniMax saw to run at 1800 fpm, it is an extremely well built saw, that's why I bought it.... c3
******************************************************
And I totally agree that the MM 16 is a well built BS. In parallel, a Mercedes is an extremely well built car....
The good news is I have never seen a Mercedes that will not push well beyond the Red Line for RPM on a tachometer.
The bad news is it won't do it very long before the "well built" Mercedes will be reduced to shrapnel as the designers had a distinct purpose for setting Red Line restrictions where they did!
But.. being a firm believer in "freedom of choice".. it's your saw!
Good luck...
Sarge.. john thompson
Hello c3incjjc,
One of the things to consider is that smaller wheels create more stress on the saw blade and slowing the speed down will help with preventing breaking of the blade.
don't speed it up to much.
Hope this helps
Jody,
Keep in mind that a smaller diameter wheel will have to turn proportionately faster than a larger wheel to attain the same feet per minute (fpm) or peripheral speed as that larger wheel.....
Your smaller wheel will turn faster and the higher rpm (revolutions per minute) will mean greater centrifugal force on the tire. If you are comfortable with that, and the rubber is in good condition, then you can get an answer, hopefully over an extended time period, by glueing the tires on the rim. Try an industrial grade contact glue.
Having said that, if it were me, I would re-check my sums, and be careful, very careful.
I am also of the opinion that bandsaw blade manufacturers like to have their blades working at fpm' speeds (not rpm) that are on the high side.
So Philip, do you agree with what I am doing?
My MiniMax 16" spec's state the fly wheel turns at 920 rpm, which equals 3700 fpm and doesn't cut very well. So I doubled the rpms to roughly 1560, which equals 6400 fpm. Hopefully it will cut as good as the 24" saw I cut on at a friends shop, which runs at 8500 fpm, and we use the same blades.
I didn't know blade companies pefferred higher speed saws, thanks for the info.
Thanks Jody
Jody,
your 16 inch diameter wheel turning at 920rpm actually gives 3855fpm (feet per minute): to me that is too fast for an ordinary wood bandsaw . Maybe I am behind the times but as far as I know 3000fpm is the upper limit and the average is around 900 to 1000fpm.
Now , don't get confused with the high speed saws that are used in industry- these are designed for much higher fpm's.
On the other hand, increasing your wheel rpm's from 920 to 1560rpm's is still not a high speed at all FOR THE WHEEL to turn at-it is only 16 inch diameter, so I see nothing wrong there, and am at a loss to explain why the tire is separating-unless the rubber is not good, or the cunning buggars have specially designed that tire to only run properly at the lower speed.
I suggest you confirm the makers recommended blade speed limits, and if your proposed changes are within these, then re-visit the tire rubber. Maybe a new tire is tighter. Try glueing the old ones. And I would also suggest checking with Minimax about increasing the revs to 1560-it does not seem a high speed to me for that small wheel, but there must be good reason why the makers set it at 920rpm. And increasing the fpm does not automatically guarrantee improved performance.
Let us know what you decide to do.
Philip Marcou
Edited 8/10/2007 8:12 pm by philip
3700 SFPM sounds a lot more likely than 950. 6400 SFPM is ridiculous for that machine and is likely to toss the tires as you've found.Back up a minute. The problem that you're trying to solve is that the saw "doesn't cut very well". This is a high-quality saw that (according to the many singing its praises on this forum) should work fine at its design speed. I recommend that you get back to basics to get your saw working well.Are you using a sharp, good-quality wood band with about 4 TPI? I'm betting you're running a band with a very high tooth count or a band that's worn out or hit something hard.If the band is good, please describe what band you're using and what you're trying to do.Pete
I agree that the problem with your saw is a bad blade(s) or very poor technique/setup. Not speed. Your saw is cutting at approximately 3850 feet per minute. This is just what it should be doing. I have demoed this saw in it's stock condition and it left nothing to be desired in terms of sawing ability, quality of the cut, freedom from vibration and ease of operation. Get some good quality, new blades - 3 tpi for reawing, 4-6 tpi for other work (I especially like Timberwolf) and review your setup methods. That saw should be giving you no trouble at all operating at 950 rpm. Rich
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