I have a Powermatic 14″ bandsaw that I bought a while ago, and have just got around to finally setting up. I noticed that there was quite a bit of movement in the blade, front to back. Not being able to adjust this with the tracking I disassembled the machine, stripping the table and anything else I thought was in the way. Checking the wheels with a 4′ level I found that the top wheel was back and that the wheels weren’t parallel with one another. I drilled out one of the holes for the post of the riser block and was able to swing the top wheel parallel with the bottom and I shimmed out the top wheel with some washers. I am still getting some movement front to back. The wheels seem very close to being true, in the top wheel it may be out 1/64″ or less on the outer rim. The movement in the blade doesn’t seem to correspond with the wheel position or the blades movement over the wheels. Could it be the tires, I notice on the bottom tire there is a little movement front to back in the tire section that isn’t under the blade.
As a side note I am a younger carpenter who saved during my apprenticeship to set up a small shop. I bought all Powermatic, a bandsaw , tablesaw and jointer. The cabinetmaking instructor at the union training center always spoke highly of Powermatic and I liked a lot of there features. Yet all the machines seem to be just kits, all required a lot of adjustment. I think they are now living off of a reputation that is no longer deserved now that the manufacturing is overseas. Buyer Beware!!! Any help would be great, thanks.
Discussion Forum
Get It All!
UNLIMITED Membership is like taking a master class in woodworking for less than $10 a month.
Start Your Free TrialCategories
Discussion Forum
Digital Plans Library
Member exclusive! – Plans for everyone – from beginners to experts – right at your fingertips.
Highlights
-
Shape Your Skills
when you sign up for our emails
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. -
Shop Talk Live Podcast -
Our favorite articles and videos -
E-Learning Courses from Fine Woodworking
-
-
Replies
Personally, I have not ever purchased a machine, or any other machined assembly product for woodworking, that did not require some level of assembly. Not even a hand plane. Most of my machinery is green, however I do own a Powermatic jointer and a Jet thickness planer, both are first rate machines. Unless you buy a used machine, and especially if the machine must be shipped, some assembly is 'part of the deal'. Fact of life. Aside from the business reality of manufacturing and shipping machinery, it also provides for a buyer/user to learn the nuances of his/her machine as it is assembled. Even if it did arrive assembled on your doorstep, you would still have to check the alignment of all the components to ensure nothing moved during transportation, and realignment is most likely necessary. Now, on to your problem.
I'm struggling to determine which direction you're blade is moving in excess. Perpendicular to the wheels or parallel to the wheels? Not sure that is important however as it sounds like you don't have enough tension on the blade.
How are you setting your blade tension, and are you sure that you have enough tension on the blade?
If you had not described everything you done already, I would have sent you down that path (checking coplaner wheels, etc..) but sounds like you've done your 'due diligence' on that. Kudos to you. Assuming the wheels are tight and there is no 'play' in the wheels (that would be a bearing problem), all that is left is the tension question, and the possibility that your tires are not up to snuff. I can not determine from your post if the machine is new or not. If it is, I would contact your tool vendor or Powermatic for assistance with the tires and possibly the tension spring. If it is not, I would just go ahead and put polyurethane tires on it. That, along with proper tension on a high quality blade, should serve you well.
If this is a new machine and you are using the blade that came with it...GET A GOOD BLADE! Most band saw manufacturers are notorious for shipping their machines with low quality (junk) blades. The stock blade is meant to keep the wheels from moving, cutting ANYTHING is a distant secondary consideration. A good blade for your machine will cost around $20.00 so it is not a big expense. New tires (if needed), new blade, and your Powermatic should be one wood cutting son of a gun...
Thank you all, Jeff, Pete, DGreen, and Brian, for responding to my problem. Jeff, to answer your question the movement is front to back when setting yourself in the position of making a cut, so I guess you would say perpendicular to the wheels. My blade is a 1/2" Olson that I tension using the gauge on the back of the saw. I know some like to get scientific about the tensioning, but according to Duginsky he finds it to be reliable. I haven't even done any test cutting to check the performance, but my concern was with the thrust bearing. How do I set the gap, at the furthest forward or back? If completing all the suggestion mentioned and there is still movement will it wear out the bearings? I'll try changing out the tires, but I don't know what to do after that, the people at Powermatic have been of no help. Maybe this movement isn't as much of an issue as I am making it, I should probably do some work with it before making mountains out of mole hills. Again, thank you all.
Look at the wheels as you turn them slowly by hand. If the wheels aren't flat and in the plane of rotation, that will translate directly to back-and-forth movement of the blade.
Assuming the wheels are okay, watch the back-and-forth movement of the blade as you turn the wheels. If the movement is a smooth, sinusoidal oscillation, then the problem is likely to be the tires. If the movement is at all jerky or has abrupt changes in direction, then it's probably the blade (although it still could be the tires).
I would try another blade in any case. If the new blade shows the same behavior, then you know the problem is with the tires (again, assuming you've eliminated a warped wheel as the cause).
-Steve
Well here is what I did after talking with a woodworking friend of mine. I clamped a scrap block to the frame of the saw, having stripped the table and any other parts that would get in the way.I then marked the blade when it began to drift forward and then made another mark when the gap closed again. I also made two reference marks on the wheels. I then turned the wheels by hand and found that the marks on the blade were consistent. The frequency of the movement didn't correspond with the wheels either seeing that I have only 14" wheels and a 105" blade, if it was the wheels I would figure that the movement in the blade would occur with every rotation of the wheel. The blade is a 1/2" Olson, I don't know how great they are? I plan on getting new tires this weekend, and a new blade, and then I'll report back. Thanks.
Olson blades work fine for me. But go for their better blade, The AllPro.Work Safe, Count to 10 when your done for the day !!
Bruce S.
Are you sure it's not a bad blade weld? Have you tried a different blade?
Paul
Back off on both thrust bearings,top and bottom. Turn the upper wheel by hand. If you see an osscilation the blade is not welded in a straight plane. If the blade seems okay, then adjust each thrust bearing. Move the bearing until it touches the back of the blade, then back off a half turn or so.The gap should be about the thickness of typing paper.Do the same for the lower thrust bearing.Adjust the cool blocks or bearings on each side the same way.When you start the saw up the thrust bearings should not turn,they will turn when you begin sawing.If the bearings are scored or do not turn easily, replace them.
mike
I think what you're describing is the band moving forward and back when it runs. The two likely causes are:
- The band is no good (usually a bad weld)
- The tires are shot
Many manufactures ship their machines with a very poor band, so if you're using the original, that is likely the problem. This sounds like a new machine, but take a look at the tires and see if they are ungrooved with a smooth crown (higher in the middle all the way around) and not dried out.
Other possibilities exist, but they're much less likely.
Pete
I know this advice is a little late but never modify the machine until you have ruled out all the other possibilities. the chances that the parts were miscast or misbored are very slight. I agree with the other posters that more than likely you have a bad band.
------------------------------------
It would indeed be a tragedy if the history of the human race proved to be nothing more than the story of an ape playing with a box of matches on a petrol dump. ~David Ormsby Gore
I have the Jet (a relative of the PM) 18" bandsaw and think in have dealt with a similar blade movement, from front to back with at least every rotation of the the wheels. On mine the groove in the wheels is slightly wider than the tires are, so if the tire is seated on one side here and the opposite side there on the wheel, and the blade wants to ride only on the fattest center part of the tire, then the result is front to back motion, which equals a pulsing/vibrating cut. So I went about scooting portions of the tire back or forth untill the oddest spots were taken care of. Now my saw behaves pretty good. I honestly believe that if I could find wider tires to fill up the wheel my saw would be near perfect. And I've never checked it for coplanar or needed to correct for drift. I guess our problem is one of the downfalls of convex tires. Anyone have experience with flat tires? I guess you'd have to set the tracking a lot more often.
Brian
This forum post is now archived. Commenting has been disabled