windancer Posted May 2, 2013 Share Posted May 2, 2013 My new Jet bandsaw keeps breaking blades. Have followed the manual instructions and it is some better, but I am only getting maybe 25 or 30 cuts. Anyone have any suggestions based on experience? Also, can I mig the busted ones to get a little more use from them? Thinking about a brass backer and a real hot spot weld, then flap disk to smooth..... Thanks Quote Link to comment Share on other sites More sharing options...
Jim Coke Posted May 2, 2013 Share Posted May 2, 2013 Greetings Windancer, How many TPI are you using?... I found a finer tooth and less pressure extends the blade life... Do you use coolant ? If not I found a little bees wax works nice.... Been using it with my hack saw for years... Hope this helps Jim Quote Link to comment Share on other sites More sharing options...
Daniel.85 Posted May 2, 2013 Share Posted May 2, 2013 What size blades does your saw take? Quote Link to comment Share on other sites More sharing options...
doc Posted May 2, 2013 Share Posted May 2, 2013 Jim's advice is good, but I'd like to know a couple of more things. Are the blades breaking at the welds and are they a good quality blade ie; Lennox, Starrett etc, not HF or some other off brand? Quote Link to comment Share on other sites More sharing options...
Pat Roy Posted May 2, 2013 Share Posted May 2, 2013 I have a Jet and had some problems. One was poor quality blades that broken on the weld. The supplier replaced that. Other problems were related to blade alignment; are you getting a straight cut? Is the blade tension correct? Are at least three teeth engaged in the material you are cutting? Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted May 2, 2013 Share Posted May 2, 2013 Are you using a wood cutting machine to cut metal? The blade speed is too fast if you are. Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 2, 2013 Share Posted May 2, 2013 A horizontal bandsaw is a metal cutoff saw. If you're getting 25-30 cuts from a blade it's a metal blade. There are a number of possible causes or combinations. Are you getting the vise tight enough, any shift and the blade will kink and later fail. I'm always having to shim the stock in the vise and sometimes it's possible to get it so tight the stock will shift because of the pressure, not common but it happens. If I'm cutting an odd shape, I clamp it however it needs to be clamped then give it a good shake to see if it'll come loose. Blade tension is really important, it should twang when plucked like a banjo string. The book should have a deflection number to adjust to. Just picking a number as example, at the back of the blade, that's the side away from the guide rolls you should only be able to deflect the band (1/2") by hand. That is just a number I picked for instance, LOOK IN THE BOOK. You can get the blade too tight which causes excessive bearing wear on the wheels. Are the guide rollers adjust correctly? I'm thinking your's are pretty close now. This is a really hard one to direct via text, the Jet book is pretty good or you can ask at a small tool repair shop, I've found the guys to be really helpful in general. I'll have to leave this one at read the book, get hands on help. The most common mistake is feeding too fast. With very few material exceptions, slower is better. Copper alloys need fast feed or it'll work harden, gall the blade and break it. Steels want a slow feed. Waxing the blade can hep but I don't recommend bees wax, parafin isn't as sticky so chips clear better and are less likely to gall. I'll get to galling the blade soon. TPI on the blade is probably the second most common mistake made. The rule of thumb is three teeth on the material. More is NOT better, a few isn't a problem but using a 32tpi blade on 1/2" stock can sure be an issue. I find it hard to get blades more coarse than 14 tpi so it takes technique to deal. There are two main issues having to do with TPI. Too coarse and the teeth will snag as there is so much pressure, the blade bends and later breaks at that point.The common mistake is thinking (logically) that more teeth is better but what happens is galling. The distance between teeth allows cuttings room to collect and be carried out of the kerf, if the tpi is too fine the cuttings build up without room, soon the blade is floating on cuttings, they heat up and gall (jam) the blade breaking it. If you have to use a too coarse blade turn the feed speed down, way down in some cases, you CAN cut exhaust pipe with a 14tpi blade but only if it's just kissing the stock or it'll hook an edge and that's that. Likewisa if all you have is too fine, turn the feed down so it's not cutting fast enough for cuttings to build up and gall. Galling is one of the worst problems but it's not too bad once you understand it. It's basically cuttings jamming the blade, a little or a lot. If it's a heavy jam it'll stall the motor and bend the blade. A little galling and it cooks the blade with friction. Wet saws use the liquid to keep cuttings cleaned out of the kerf, not lubrication, not cooling. Not directly that is, if cuttings are cleared quickly very little heating will occure and the saw teeth are cutting and need no lubricant. A touch of wax can help but just a touch. Too much and it's like glue sticking cuttings to the blade with eventual bad results. Parafin isn't a tacky wax so it's my preference. A drop of oil is almost the worst thing cuttings stick to it like feathers to tar. Dry graphite lube works a treat but gets on everything, PITA of a mess. Alll that said, you're getting 25-30 cuts so your saw is set pretty close, I'd GUESS it's blade tension or incorrect TPI, provided you're cutting common steel, a little inclusion will eat blades. I have a 7"x14" JET horizontal vertical bandsaw and use the heck out of it. Frosty the Lucky Quote Link to comment Share on other sites More sharing options...
windancer Posted May 2, 2013 Author Share Posted May 2, 2013 Wow! Thanks fellers.. The saw is metal cutting. No coolant. Will try some paraffin and see if that helps. I never oil or WD40 the blades. High quality blades, always. They are NOT breaking at the factory weld. I have the weight/pressure dialed way down. The cuts are not perfect but certainly acceptable. Cutting at the slowest feed rate. I still think it is the blade bearings. I am building a heavy bolster to hold RR Spikes to bash on the heads. 10 spikes, three cuts on each. Broke two blades. Noticed today that the blade is really screaming as it nears the end of the cuts. I agree that it is close or the cuts would be out of square one way or the other. I am on my way back to the shop now- will post back after I realign the dang guides again and see if that, and the paraffin make any difference. I love the saw and the way it works, but I am NOT willing to just keep breaking the blades. Any input about mig or spot welding the blades as they break? Thank you all again for the ideas :) Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 2, 2013 Share Posted May 2, 2013 A screaming blade is most often a sign the stock is vibrating in the vise. Try shims or repositioning them. Loose stock will break blades it only has to shift a few thou. You need to be able to heat treat blades if you weld them. It's usually done in the lap welder that welds them, it brings the join to red heat and lets it air cool. I think you'd have better luck gas butt welding and letting it normalize afterwards. weld, grind, reheat and air cool just might work. No bets though. Frosty the Lucky Quote Link to comment Share on other sites More sharing options...
bosox Posted May 6, 2013 Share Posted May 6, 2013 Read this informative article. . Quote Link to comment Share on other sites More sharing options...
ptree Posted May 10, 2013 Share Posted May 10, 2013 I have had several Jet saws and find them a nice saw. For RR spike thickness I use a Lennox Diemaster II blade in the 9-14 tooth vari pitch style. Best I have tried. They come with high quality factory welds and are a Bimetal blade, meaning tool steel theeth on a flexible back. I use a little stick lube, this particular stick is LPS brand, works nicely. If you have screaming blades then sound like loose in the vise to me. Quote Link to comment Share on other sites More sharing options...
windancer Posted May 10, 2013 Author Share Posted May 10, 2013 The vise is good and tight. Had been running Lennox blades and switched to a different high-quality blade to see it it would make a difference. It didn't. I have always run bandsaw blades as tight as I can get them. I read through the manual again twice. I see they recommend a little play in the blade. Against all my ideas I went ahead and loosened it a little- the loosened blade has made many, many cuts and is still going strong. I am not convinced yet, but the results looks better..... Quote Link to comment Share on other sites More sharing options...
ptree Posted May 10, 2013 Share Posted May 10, 2013 I have seen too tight blades cup and start cutting in a radius vertically, and quick failed. Also death to the rather small bearings on these little saws. Tighter does not equal straighter. Quote Link to comment Share on other sites More sharing options...
windancer Posted May 11, 2013 Author Share Posted May 11, 2013 Made a few more cuts today, still the same blade... Quote Link to comment Share on other sites More sharing options...
bosox Posted May 20, 2013 Share Posted May 20, 2013 Breaking band saw blades is a huge headache, I can't afford it to happen. I got not so expensive blades, They cut very well and I can't recall breaking issues about it. Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 20, 2013 Share Posted May 20, 2013 too tight is a fast way to break blades and damage the wheels bearings and cause the wheels wobble. You want the blade to twang when thrummed, not ptk. I routinely cut RR rail in my 7"x12" Jet using 14tpi monosteel blades and get dozens of cuts through rail. You have to position the rail correctly or the induction hardened wear surface will kill a blade instantly. Upside down with the flange tilted slightly towards the direction the blade is coming from. This way the blade isn't cutting the hardened face, it's chipping it out from the back. One more trick, dirty steel will wear blades quickly a little wire brushing on the cut line can mean lots for blade life. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
windancer Posted May 21, 2013 Author Share Posted May 21, 2013 Well, broke another blade. These blades are not even well broken in when the break. I have owned many band-saws over my lifetime and never had this happen before. I am going to strip it completely down and start from scratch. I have worked my whole life with power tools. I am not hard on equipment- tools are expensive and I do not abuse them. The steps in the manual do not correct the problem. i hardly ever lose my temper but this saw is making me crazy. The 6 guides are all set just shy [couple thousandths] of touching the blade. The cuts are more than adequate and are square both directions. If this is still going on after my last try it will be gone. Any goofy, stupid or ludicrous ideas are more than welcome. Dave Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 21, 2013 Share Posted May 21, 2013 It sure could be a bum machine. If so, Craigslist? Oh wait, that probably wasn't goofy, stupid or ludicrous enough was it? Hmmmm, grind the teeth off the blade and use it as a meat slicer? On a more serious note, have you just run it for a while without cutting? Just let the band go and see what happens? How do the cuts themselves look? Are the cut marks uniform or are there steps? The static jaw of the vise's angle and pivot bolts, are tight and 90* to the blade, yes? Clean between the static jaw and bed? Uh, is there any play in the pivots the saw hinges on? Is the hydraulic lowering cylinder and valve jump and grab? Air in it somewhere maybe? Or is it a spring retarder, is it smooth? I'm really reaching now but I'll give it more thought, I have some stock to cut for an upcoming clinic so I'll take a close look at mine and see if I can think of something that could go wrong with it. That's tough though, they're so darned simple. High explosives and a suicide note written with broken blades? Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
bosox Posted May 21, 2013 Share Posted May 21, 2013 Does it break while cutting ? Quote Link to comment Share on other sites More sharing options...
windancer Posted May 22, 2013 Author Share Posted May 22, 2013 yup.... Quote Link to comment Share on other sites More sharing options...
windancer Posted May 22, 2013 Author Share Posted May 22, 2013 Got the saw torn down today and put on a new Lennox blade. Set the blade tension to the manual. Changed the belt speed and set the belt tension to the manual. Set the blade tracking to the manual. Set the blade guides to the manual. Set the blade bearing weight to the manual. Cleaned up the goop and grit. Will set the blade bearings to the manual in the morning and recheck that all is still to specs. One more try- the final one. Thanks to all for the suggestions. Dave Quote Link to comment Share on other sites More sharing options...
bosox Posted May 22, 2013 Share Posted May 22, 2013 And follow the blade break-in procedures. Quote Link to comment Share on other sites More sharing options...
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