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View Full Version : Bandsaw Saw down hill....



David Nelson1
05-13-2010, 7:32 PM
Cutting tenons on the BS the other day and I noticed that the blade never touched the the scribe mark on the bottom. I didn't think much of it right then, but went back a bit later to have a look see and placed a square againts the back of the blade and the table. In 12 inchs its out by @ least 3/16 of an inch. Only thing I can come up with is that the trunnion bracket is bent or something got caught under it when I was assembling. I didn't see an adjustment of any kind so..... has anyone ever seen this before? BTW the BS is a brand new Jet 14DXPro. Thanks in advance.

Ken Fitzgerald
05-13-2010, 7:47 PM
David,


Could it be that your table is tilted and isn't square to the blade?


If it is, could the tension on the blade be too low and allowing the blade to move into the area of least resistance within the wood?

David Nelson1
05-13-2010, 8:07 PM
Nope, its off in the direction of travel not the way the table tilts and the blade is good n tite. The blade is square to the table as well as to the miter slot.

Ken Fitzgerald
05-13-2010, 8:50 PM
David,

It sounds like one of 2 things to me then.

1. I'd check to see if your wheels are co-planar

2. See if the blade is riding on the front edge of one wheel and the back edge of the other wheel.

I can't see how any type of blade guide system would allow that to happen if the blade is on the wheels correctly and the guides are adjusted correctly.

Thomas Knapp
05-13-2010, 11:28 PM
Nope, its off in the direction of travel not the way the table tilts and the blade is good n tite. The blade is square to the table as well as to the miter slot.
Are both of your thrust bearings set correctly? The bottom one could be pushing the blade too far forward. They should just lightly touch the back of the blade when the blade is free running. They can even be the thickness of a piece of paper away from the blade when no pressure is on the blade.

Keith Westfall
05-13-2010, 11:37 PM
You may have to shim the trunnion mounts which should bring it to square. Sucks to have to do it on a new machine but...

Thomas Knapp
05-13-2010, 11:41 PM
Cutting tenons on the BS the other day and I noticed that the blade never touched the the scribe mark on the bottom. I didn't think much of it right then, but went back a bit later to have a look see and placed a square againts the back of the blade and the table. In 12 inchs its out by @ least 3/16 of an inch. Only thing I can come up with is that the trunnion bracket is bent or something got caught under it when I was assembling. I didn't see an adjustment of any kind so..... has anyone ever seen this before? BTW the BS is a brand new Jet 14DXPro. Thanks in advance.
You mention the bandsaw is new. Are you new to seting up a bandsaw? Do you know the routine? back off all guides, install blade, Tension blade , check tracking on wheels, adjust guides to blade. Also what kind of blade are you trying to cut tenons with? A 1/4' blade can deflect more then a 1/2" blade. A blade with too many teeth for the stock thickness won't clear out the sawdust efficiently.
Do you feel much resistance when you are feeding the wood into the blade?
Of course you may already know these things and have prior bandsaw experience.

Bill Wyko
05-14-2010, 1:38 AM
When you turn the saw on, do any of the guides make a sound? If bearings, are they spinning? The bearing behind the blade may be against it, pushing it towards you.

David Nelson1
05-14-2010, 4:27 AM
Thanks for the suggestion guys I'll take a better look this evening

David Nelson1
05-14-2010, 4:32 AM
Hi thomas, I followed the instruction to the T because this is my first band saw. the BS cuts great no wondering or excessive effort. I even resawed a few small pieces of pine with it. I think its a 1/4 width and does have quite few teeth. Its the OEM blade.



You mention the bandsaw is new. Are you new to seting up a bandsaw? Do you know the routine? back off all guides, install blade, Tension blade , check tracking on wheels, adjust guides to blade. Also what kind of blade are you trying to cut tenons with? A 1/4' blade can deflect more then a 1/2" blade. A blade with too many teeth for the stock thickness won't clear out the sawdust efficiently.
Do you feel much resistance when you are feeding the wood into the blade?
Of course you may already know these things and have prior bandsaw experience.

David Nelson1
05-14-2010, 4:46 AM
No, Bill it doesn't seems that that is going on. I just went out and looked again keeping in mind the suggestion from everyone. I found the upper back guide to be farther away from the blade than I remember setting it up for. I also found that the blade is riding farther on the outside of the upper tire than it is on the lower. During setup I adjusted the blade to track in the middle ( I can't remember looking @ the lower tire for comparison to the upper during setup) I think I will blow the dust off everything this evening and go back through the setup adjustments again. I'll report back this evening.




When you turn the saw on, do any of the guides make a sound? If bearings, are they spinning? The bearing behind the blade may be against it, pushing it towards you.

David Nelson1
05-14-2010, 6:53 PM
I went back over the settings and found that the lower roller guide was not square to the blade but that wont cause what I'm seeing. I removed the table, inspected the trunnion base plate, the mating surface for the trunnion mount, and the trunnion themselves. I then took a bubble level looking for a stable place to compare the machine base and the table. No luck with that at all.

The saw comes in 2 boxes. The base and the saw with the table unassembled. THe upper portion is bolted together from the factory. This is the area I think is the problem. Possible the riser area was mismachined or the trunnion area?? no way to tell with no level reference areas.

Sorry about the size of the photos cell phone was the only camera with batteries.
Any comments.

Mike Cruz
05-14-2010, 8:06 PM
I would have to guess that your wheels aren't co-planer. If you have checked thatand the blade is riding in the middle of both wheels, then the problem must be in the table/trunion. I suppose either shimming or removing stock from the front trunion would help. By trunion, I mean the two pieces that allow the table to move. I've seen them called trunions on one of my band saws and I think they are called something else on the other.

David Nelson1
05-14-2010, 8:17 PM
"I would have to guess that your wheels aren't co-planer."

The blade is riding in the middle and moves evenly on the top wheel as well as the bottom. How would you suggest checking the wheels for co-planer.

Mike Cruz
05-14-2010, 9:20 PM
I will address co-planer in a moment...

What do you mean the blade moves evenly on the top wheel as on the bottom? Do you mean to say that while running it moves back and forth? Or do you mean while adjusting. If the latter, good. If the former, bad.

As for checking for co-planer, with the front cover/s off (and usually the table gets in the way, too, so you might want to take it off), take a straight edge (you will probably need at least a 4 footer, if not 5) and place it so that it spans the top of the top wheel and the bottom of the bottom wheel. The straight edge should also touch the bottom of the top wheel and the top of the bottom wheel. Make sense? In other words, the two wheels should be running directly in line with one another. Neither should be behind or in front of the other, nor should either be tilted/leaning backwards or frontwards. Get the picture?

It sounds to me like your upper wheel is forward of your bottom wheel. With the blade running in the middle of both wheels, that would draw the blade forward at the top, like in your picture (if I remember it correctly).

Any more questions, feel free to ask, even if I can't answer them...like how to fix non-co-planer-icity. ;)

David Nelson1
05-14-2010, 10:03 PM
Mike,
I was talking about when adjusted. Sorry bout the confusion there. The co-planer idea sounds worth while I have a 4 foot machinist straight edge not sure its long enough this this saw takes 105 in blade. If not I'll straighten out a 2X4 and see what I get. Thanks for the idea.

Van Huskey
05-14-2010, 10:35 PM
I wanted to wait until this thread matured before I jacked it but reading the title I couldn't help but think of Jim O'Dell's Grizzly 690 flipping out of his truck and rolling down the hill... :D

David Nelson1
05-14-2010, 11:01 PM
Well that would have made just as mad as this LOL

Ed Griner
05-14-2010, 11:17 PM
Could the upper blade guide post be out of alignment relative to the blade.When I installed Carter guides,it became very obvious,the guide post mounting had been manufactured with a slight boo-boo.Its a 14" delta(1948).I was able to correct the condition(one of many). Good Luck with your problem,I'm sure if you stick it out,you will find the problem. Ed

Chris Parks
05-15-2010, 4:46 AM
Cutting tenons on the BS the other day and I noticed that the blade never touched the the scribe mark on the bottom. I didn't think much of it right then, but went back a bit later to have a look see and placed a square againts the back of the blade and the table. In 12 inchs its out by @ least 3/16 of an inch. Only thing I can come up with is that the trunnion bracket is bent or something got caught under it when I was assembling. I didn't see an adjustment of any kind so..... has anyone ever seen this before? BTW the BS is a brand new Jet 14DXPro. Thanks in advance.

My Jet 18" had the same problem and there is an adjustment, I just have to remember what it is. I will get back to you after I have had a look at the saw. Ok, had a look and this is what I remember. Remove the table from the trunions and the black plate that is held onto the the frame of the saw has some grub screws in it. release the hexagon bolts that hold the black plate/trunions to the frame and adjust the grub screws as required then tighten the hexagon bolts. I would not overtighten the hex bolts as now there will be clearance to the frame on one side. I had to fix mine and it has stayed fixed for some years.

David Nelson1
05-15-2010, 8:11 AM
Mike,
The wheels are out of co plane by .007. Not enough to adversely effect the operation of the saw. So finding the edges of the wheels as the most dependable area to measure from I leveled the saw to and fro.

Chris,
I removed the table and the trunnion brackets. I looked at the grub screws as a means of adjustment. On this saw they are guides to align the trunnion mount plate and they index into blank holes. I don't know what your set up looks like but take a look @ the pics posted below.

Kris,
I think you hit the nail on the head with the shimming. Originally (yesterday) I was thinking the area in question was the riser to the base (as pictured in a previous post), but this sets up another problem. The upper and the lower wheels running out of square with each other. The amount of deviation I'm seeing (co-planer) would be greater going this route.

I leveled the machine and placed a a machinist level on the trunnion mount of course it was off. I shimmed it .017 and this brought the bubble to a relative center. I going to go by a junk feel gauge and use the feelers as shims. Don't own any shim stock anymore threw it away when I sold the last of my machines so feeler gauges will have to work.

This might get me in the ball park but right now my confidence is low due to sloppy machining on the part of the manufacture. More to come!!!!!

Chris Parks
05-15-2010, 8:20 AM
Chris,
I removed the table and the trunnion brackets. I looked at the grub screws as a means of adjustment. On this saw they are guides to align the trunnion mount plate and they index into blank holes. I don't know what your set up looks like but take a look @ the pics posted below.



The pics are to small to see any detail. The grub screws level the trunnion brackets on mine so by default level the table. A bubble level placed on the machine will only reflect the floor level it is sitting on. A digital level referenced off the blade will give you the correct answer.

David Nelson1
05-15-2010, 8:50 AM
My grub screws are pressed in and have no means of adjustment, say like a threaded stud with a slot for a screw driver. Sorry bout the pics the large camera has no batteries but I'll get some this morning.

I leveled the machine relative to the upper wheel not the floor so the back of the blade should as be perpendicular to the axis of the upper wheel.

The placement of the level on the trunnion mounting pad was to pick off a reference relative to the axis of the upper wheel. These two points should be parallel to each other in order for the table to be level in both direction.

As you have pointed out the table needs to leveled by some means but I don't think your method will work on my saw due to the pressed in plastic plugs and the trunnion block had a very deep blind hole that these plugs align with.

I'll take better pics for clarity. Maybe I'm missing your point or the means to the end of your point. Thanks for the input.


The pics are to small to see any detail. The grub screws level the trunnion brackets on mine so by default level the table. A bubble level placed on the machine will only reflect the floor level it is sitting on. A digital level referenced off the blade will give you the correct answer.

David Nelson1
05-15-2010, 10:27 AM
Thanks everyone!!!!!! ;) .020 feeler gauge blade under the trunnion block brought the table square with the back of the blade. A few test cuts provided proof positive that the top postion of the kerf = the bottom kerf down to the 1/64th.