LumberJocks

Bandsaw blade won't stay on

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by Washam posted 07-09-2020 07:58 PM 961 views 1 time favorited 33 replies Add to Favorites Watch
View Washam's profile

Washam

21 posts in 424 days


07-09-2020 07:58 PM

Afternoon Guys, quick question concerning my 14 inch Delta bandsaw if you please. The saw has “thrown” the blade3 times in the last week. The blade comes off of the front of the wheel. The wheels are coplaner and the tires are Carter and Son urethane aprox 5 yrs old. The guide blocks are original to the saw but in good condition and the thrust bearings are adjusted properly.
The first time I checked the wheel alignment and clean both the tire surface and the blade (both sides) (woodturners 3/8”); the second time, I went thru the same routine. The third time this morning, I removed the wheels and tires and cleaned both, soaked the tires in 130 degree water with the thought that the heat may cause the tires to shrink back to the original diameter when they cooled on the wheels, realigned all components, reinstalled the blade and you guessed it, it came off after about a minute of cutting an 8 inch bowl blank – no tight turns. I’m at a loss for additional actions. The only thing I noticed after the 3rd incident this morning was that while the tires did seem to shrink back tight on the wheels, I could move the tire(s) from side to side on the wheels after the fact. I’m bettin’ that the tires are toast; what do you think; any other points I’ve over looked?
If you think new tires are in order, any suggestions? The Carter and Son tires are only about 5 yrs old and the saw is used less than 3 times a month. These tires were expensive and I would have expected them to last a lot long.

Thanks in advance,

John


33 replies so far

View shampeon's profile

shampeon

2154 posts in 2988 days


#1 posted 07-09-2020 08:18 PM

Unless the tires are coming off with the blade, I don’t think it’s the tires that are the problem.

You don’t need the wheels to be coplaner. That’s a persistent misconception.

The Snodgrass setup video:
https://youtu.be/wGbZqWac0jU

-- ian | "You can't stop what's coming. It ain't all waiting on you. That's vanity."

View HokieKen's profile

HokieKen

14503 posts in 1943 days


#2 posted 07-09-2020 08:28 PM

Have you tried a different blade John? That’s always my first stop with seemingly inexplicable bandsaw issues. Could be a twist or a bad weld that causes it to jump off when under pressure. Second thought is to make sure your tracking adjustment is locked down and that it really does lock down. Finally, are you sure it’s got enough tension?

One other thought comes to mind. Where does the blade ride the wheels when you put it on? Is the back of the blade riding the crown? If so, try adjusting the tracking so the crown hits closer to the gullets.

-- Kenny, SW VA, Go Hokies!!!

View Lazyman's profile (online now)

Lazyman

5655 posts in 2192 days


#3 posted 07-09-2020 08:33 PM

Kenny pretty much covered everything I would suggest trying but I just wanted to add a +1 on trying a different blade. I have one blade that won’t stay on no matter what I do even though there is nothing obviously wrong with it. I have no problems with any other blades.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View MrUnix's profile

MrUnix

8159 posts in 3004 days


#4 posted 07-09-2020 08:39 PM

It would be helpful if you could watch the tires while in action. You should not be able to move them. If you can, then you probably need to glue them down.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View oldrivers's profile

oldrivers

2240 posts in 2372 days


#5 posted 07-09-2020 10:39 PM

The video linked on Shampions post is excellent, thank you sir.

-- Soli Deo gloria!

View Washam's profile

Washam

21 posts in 424 days


#6 posted 07-09-2020 10:53 PM

Shampeon -have seen the Snodgrass vid but it’s been a while. I’ll check it out again. I’ve always set the wheels coplanar w/o problem but that doesn’t mean it’s a necessity thanks.

Hokie Ken & Lazyman: Well, Duh! That thought hadn’t crossed my mind since the current blade had always run true. Blade is running dead center on the center of the tire (don’t think the Carter & Son tire has a crown per se but the wheel does so we’re good there but will try a different blade Saturday & report.

Mr.Unix: Can’t see any movement in tire when running but can slide it side to side slightly when stationary. The blade has no wobble while running. Can’t watch it while actually making a cut. Had always heard that urethane tires shouldn’t be glued but will do some more research.

Thanks to all, the quest continues.

John

View MrUnix's profile

MrUnix

8159 posts in 3004 days


#7 posted 07-09-2020 11:19 PM

Mr.Unix: Can’t see any movement in tire when running but can slide it side to side slightly when stationary. The blade has no wobble while running. Can’t watch it while actually making a cut. Had always heard that urethane tires shouldn’t be glued but will do some more research.

No.. Urethane tires generally do not need to be glued, which is a feature a lot of people prefer… however, if they become stretched or damaged in any way, they do need to be glued down just like the rubber tires. The centrifugal force combined with the resistance to the blade when cutting can cause the tires to do some strange things, including lifting and bunching under load if allowed to.

If you are positive that your tension/tilt mechanism is not damaged, which is a distinct possibility, then the loose tires are about the only other thing I can think of that will cause blades to jump off. You didn’t mention checking the tracking/tension mechanism, so that would be the first place I would look. It is a weak spot on these saws. Pull the upper wheel to get a good look at the tilting bracket (upper wheel hinge) – make sure it’s not cracked or warped/bent.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View shampeon's profile

shampeon

2154 posts in 2988 days


#8 posted 07-09-2020 11:20 PM

+1 to Hokie Ken’s suggestion of setting the blade so the gullet is at the center, not the center of the blade. It’s probably the biggest takeaway from the Snodgrass setup video. Try that with the suspect blade before tossing.

A lot of people that run, like, 1” resaw blades will quibble with the centered-gullet thing, but for typical non-production bandsaw blades and sizes, it’s a good rule. I suspect blades 3/4” and wider have enough stiffness to resist not being supported just behind the gullet, but a 3/8” blade that is centered on a crowned 14” bandsaw tire is (usually) not going to track straight.

-- ian | "You can't stop what's coming. It ain't all waiting on you. That's vanity."

View Rege's profile

Rege

3 posts in 2759 days


#9 posted 07-09-2020 11:43 PM

If it was running fine and suddenly started throwing blades check the tracking pivot point. You might need to pull the blade tensioner to see it. Mine started throwing blades… tires looked fine, changed the blade, checked bearings for excessive slop. After an hour and a half screwing around I decided to strip it down clean everything and put it back together. As soon as I took the tensioner out of the the slot I found the pivot was cracked. Found one on Amazon for $80 bucks with shipping. It has worked fine since but I have no clue what caused it to crack.

View splintergroup's profile

splintergroup

3864 posts in 2027 days


#10 posted 07-10-2020 03:51 PM

I’m with the damaged tensioner bracket crowd. I’ve read many posts here and elsewhere describing the exact same symptoms with no obvious fault. The bracket was the root of all evil in nearly all of these instances.

View johnstoneb's profile

johnstoneb

3146 posts in 2978 days


#11 posted 07-10-2020 04:03 PM

I would look at the tensioner and tracking bracket also. Tracking adjustment gullet should be center of the wheel. Co planar wheels in theory are nice but once you adjust tracking on that top wheel they are no longer coplanar.
If the tires are loose either glue them down or replace them a moving tire will change the tracking line as it moves.

-- Bruce, Boise, ID

View Washam's profile

Washam

21 posts in 424 days


#12 posted 07-10-2020 07:59 PM

Latest episode of my bandsaw blade wants to be a bird and take wing! :-)

I rewatched Alex Snodgrass’ video last night and again this morning. I completely disassembled all the adjustable parts -and some that weren’t adjustable on my 35 yr old Delta 14 “bandsaw, did a complete cleaning and reassembled and adjusted as Alex recommended (and yes, I forgot about the coplaner as Shampeon and Alex suggested). I put the same blade on the saw to hold variables to a minimum, tensioned and tracked correctly, fired it up -free run, no cutting and this time not only did the blade come off but the tire came with it!
I checked the tensioner and it was fine – no cracks, reassembled and hit the switch this time watching the upper wheel and tire. After about 45 seconds, I could see a bulge developing in the tire at about the 5 o’clock position. I’m assuming this is caused by the tire stretching and centrifugal force and the blade tension. I shut the saw down b/4 it could throw the blade, examined the tires and then reversed them and turned inside out. The problem bulge did not reappear to the same degree but “ripples” were noticeable in the tire. At this point, I didn’t see any use in trying another blade since the problem seemed obvious.

So my conclusion from all of this is the tire(s) although only 5 yrs old have stretched to the point that they are no longer gripping the wheel tight enough and causing a “wrinkle/bulge” that results in the blade derailing .

Guess I could try to glue the tires to the wheels as some have suggested but not sure what type of glue to use with urethane tires so I’ll probably invest in a new set. Any suggestions on a good, reliable tire? The current ones are Carter & Son and I’d like to try another brand that might last longer.

Thanks to everyone for all the help and ideas.

John

View pintodeluxe's profile (online now)

pintodeluxe

6175 posts in 3618 days


#13 posted 07-10-2020 08:05 PM

The tensioner mechanism can actually crack and fail. It isn’t always obvious, until you take it apart.
Mine broke (Jet bandsaw) and needed to be replaced. Quick, easy and fairly inexpensive to fix.

If it’s the tires, it might be tough to get OEM Delta parts. Don’t know what brand of tires to recommend. I’m still on my original tires from the 90’s.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View HokieKen's profile

HokieKen

14503 posts in 1943 days


#14 posted 07-10-2020 08:11 PM

Unless it’s in a production shop, those tires should last for most of the life of the saw. 5 years is way too short.

The only time I ever bought tires for a saw, I bought them from this seller on Ebay. If they don’t have your model listed, just contact them and they’ll either point you to the right ones or custom make them for you. Their prices are fair and the tires lasted 5+ years on the saw I put them on and showed no signs of wear when I sold the saw. They were kind of a PITA to get on IIRC but once I did, they were right and tight!

-- Kenny, SW VA, Go Hokies!!!

View shampeon's profile

shampeon

2154 posts in 2988 days


#15 posted 07-10-2020 08:24 PM

I wonder if the urethane tires you replaced the originals with were the wrong size? Not trying to be contrary, but it’s hard for me to believe that urethane tires would stretch that significantly over 5 years.

The consensus on OWWM seems to be that rubber tires you glue on are better than urethane. They do need to be crowned, and there’s a ton of threads on doing it with jigs, doing it freehand on the bandsaw, etc.

-- ian | "You can't stop what's coming. It ain't all waiting on you. That's vanity."

showing 1 through 15 of 33 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com