Guide Bearing Adjustments

High_Water · March 22, 2021, 04:16:21 PM

I noticed my blade guide bearings were at 2 different heights (Timberking 1400). I was noticing that I would get an occasional board where one edge was slightly different thickness than the other but what really clicked in my head was that I noticed the lead bearing was not always spinning when the blade was in the log. At first I thought I was just feeding too slow but then I remembered the thickness issue and finally figured it out.

So the issue is, now that my blade is parallel to my bunks, the lead bearing still barely touches the blade, I know they are supposed to be offset a little bit from the wheels but I'm not sure if I need to adjust them both down or what. I'm sure TK has a recommended offset but I couldn't find it online, but I have the manual somewhere lol. I don't want to just randomly make adjustments and it seems strange that one bearing would contact better than the other if the blade is parallel to the bunks, unless maybe my bunks are torqued? I also don't want to have to adjust my ruler or have to compensate somehow with the blade tension settings.

Any thoughts on next steps.

JoshNZ · March 22, 2021, 04:26:46 PM

If you are talking about your blade guides they should both be pulling the blade down from the band wheels about 1/4", since they only support from one side this down force it what provides the support. Then adjust which ever one neccesary to get them both parallel to the bunks. Then measure the distance between your bunks and a tooth set towards bunks, and calibrate your ruler to this value.

YellowHammer · March 22, 2021, 10:50:44 PM

Yep, exactly. The down pressure keeps the band from floating down off the roller guide, so controls the cut better. It also applies enough pressure from band to the roller guide to keep the band from skipping and flat spotting the roller guide.

terrifictimbersllc · March 23, 2021, 12:55:31 AM

What they said. However if you can't see how both equal down pressure and parallel to bed is achieved then consider also that depending on the mill adjustments which are available, either the head or the bunks may also need to be adjusted.

On my mill one first adjusts blade tracking, then blade tilt parallel to frame with no roller guides, then checks parallel and equidistant from each bunk (bed rail) by checking and adjusting any of those if needed, after that puts on rollers and gets the 1/4 inch down pressure which leaves the blade parallel to frame. I'm leaving out a 1/16" difference on one side which may not apply to your 4post mill as well as discussion of in/out position and tilt of rollers, and adjusting the movable guide arm if your mill has one .

Bottom line obtain and completely understand your alignment procedure.

Good luck!

ladylake · March 23, 2021, 05:54:35 AM

Get the blade parallel with the deck without the guide rollers touching then apply 1/4" down on both guide rollers. Steve

High_Water · March 31, 2021, 09:16:30 AM

I finally got around to readjusting my guide rollers. First thing I had to do was get the arm on the adjustable side running parallel to the bunks, then I reset the rollers offset to 1/8" per TK manual. The most difficult part was adjusting the parallel arm, and the thing that made it difficult was the fact that I don't own any good levels, and I dropped the one I do have halfway through which can't be good for it. All said and done my adjustment through the full width of the blade height varies less than the thickness of the blade - I call that good, I suppose it would be possible to get it tighter but there's already that much flex in the metal of that arm I don't think its worth chasing. Not nearly as difficult as I'd expected, now I've got the super fun duty of changing the second of the two drive belts now that the one I already replaced has shown me what I already knew - that the other old one is a little stretched out and needs to be replaced as well, not sure why I thought I could get away with only changing one lol.

High_Water · May 11, 2021, 09:18:09 AM

So I couldn't stop myself from tweaking things that didn't need tweaking, and now my saw is doing something its never done before. When starting a cut, if the blade hits the log going too fast the blade will twist (the teeth pull down). I don't mean the blade dives in the first few inches I mean it pulls off the rollers and the teeth hit the guide arm and I stop the saw and have to make my approach super slow. My first thought was not enough down pressure even though I tried to set it back to factory settings. Has anybody experienced this before?

alan gage · May 11, 2021, 09:52:47 AM

Quote from: High_Water on May 11, 2021, 09:18:09 AM
So I couldn't stop myself from tweaking things that didn't need tweaking, and now my saw is doing something its never done before. When starting a cut, if the blade hits the log going too fast the blade will twist (the teeth pull down). I don't mean the blade dives in the first few inches I mean it pulls off the rollers and the teeth hit the guide arm and I stop the saw and have to make my approach super slow. My first thought was not enough down pressure even though I tried to set it back to factory settings. Has anybody experienced this before?

Is it doing that with a brand new blade?
Alan

YellowHammer · May 11, 2021, 12:00:53 PM

My guess is the teeth set has been removed from one side of the band because it has rubbed something metal on one side, or when it hops over the shoulder it's riding too far back on the roller guide which acts just like a desetter.

If you put on a new band, see how it rides by turning the band wheels slowly by hand to make sure it's tracking correctly and to make sure you don't de set the teeth. Check how it's riding on the belts, wheels, roller, everything. Make sure the roller guides are not contacting the band teeth anywhere within the setting region. The gullet should be proud of the end of the roller guide. Then fire it up and see what it does, and check again. Make sure the teeth aren't rubbing on anything, also. Look for shined places.

Then put it into a log and check again. It it jumps or rides off the back of the roller at any time, the band could be bad within a few seconds.

ladylake · May 11, 2021, 02:34:09 PM

Make sure the blade is level with the deck, check close to both guide rollers. 1/4 down pressure works better than 1/8 down pressure. Steve

Lasershark · May 11, 2021, 03:02:12 PM

Question: When I was realigning my mill after switching from 1.25" bands to 1.5", I found that I couldn't lower the idle side roller guide block more than 1/8" because I was bottomed out, so it's set to deflect only 1/8" instead of the recommended 1/4".

What's the mostly likely explanation for bottoming out too soon on the guide block?

High_Water · May 12, 2021, 09:04:33 AM

I readjusted my guides horizontally to get my 1/8th clearance behind the blade on the roller because it was only about 1/16th, when fixing that I noticed one of the rollers wasn't quite square to the blade so I fixed that as well. I think you are correct about the teeth being out of set because I'm pretty sure they scraped metal at one point, it worked fine cutting a 3' long 8" dia log into stickers but I put on a bigger log to see what it would do and it cut poorly. I'll put a new blade and check before I add more down pressure.

Magicman · May 12, 2021, 09:25:49 AM

Quote from: High_Water on May 12, 2021, 09:04:33 AMI noticed one of the rollers wasn't quite square to the blade so I fixed that as well.

The rollers should not be square with the blade. They need horizontal tilt toward the direction of the incoming blade, which in my case is toward the left.

Then if/when the back of the blade contacts the blade guide flange it is pulled up and into closer contact with the roller.

Beavertooth · May 12, 2021, 09:41:19 AM

With all due respect Magicman I think you accidently typed that wrong. They need horizontal tilt toward the outgoing side of the blade so the blade will touch the roller flange on that side to be pulled up against the roller. If it touches the flange on ingoing side it will be pulled down away from blade

Beavertooth · May 12, 2021, 09:42:58 AM

The last sentence in the previous most was suppose to say be pulled down away from the Roller (not blade)

Magicman · May 12, 2021, 10:17:12 AM

Facing the roller, my blade is coming from the left and the roller is turning counter-clockwise which means that the right side is going upward. With the proper horizontal tilt to the left, the right side is the closest to the blade and will contact the blade first and pull the blade upward and into the roller.

This is what I said in Reply #12 above and applies to my Wood-Mizer LT40. If a sawmill is set up and the blade moves the opposite way, then turn it around.

High_Water · May 12, 2021, 10:54:17 AM

I understand the principal behind the argument for making the side that pulls up point of first contact, but I feel like that's trying to adjust for a few thousandths over the length of contact which is maybe 2 inches. I need a longer straight edge to check with and I'll take a look and see, but I've got a feeling I may end up pulling all my hair out trying to make that small of an adjustment because everything will move with each half degree tightening of a bolt with my skill set.

Magicman · May 12, 2021, 11:10:36 AM

Quote from: High_Water on May 12, 2021, 10:54:17 AMI understand the principal behind the argument

There is no argument from me. My Wood-Mizer Operator's Manual gives me the alignment procedure and I follow it. They have the R&D to establish their guidelines, not me.

High_Water · May 13, 2021, 09:07:32 AM

Quote from: Magicman on May 12, 2021, 11:10:36 AM
Quote from: High_Water on May 12, 2021, 10:54:17 AMI understand the principal behind the argument
There is no argument from me. My Wood-Mizer Operator's Manual gives me the alignment procedure and I follow it. They have the R&D to establish their guidelines, not me.

My manual just says to square it up, or at least I'm 98% sure that's all it says I'll read through it one more time though just in case I missed it.