LT40 Moveable Guide Arm Pulleys...Damaged?

[Ga Mtn Man]

I whacked my moveable guide arm pretty hard over the weekend... hard enough to bend the blade guard.  I was checking it over for damage and found that, when fully closed, I could tug on the arm and move it fore and aft about ¼" in each direction but it returns to center when I let go .  All of the v-pulleys have a slight wiggle when I do this but the upper inside one wiggles noticeably more than the others.  The arm is very rigid in the vertical direction.  Is the horizontal movement normal?  I never really took notice of what "normal movement" is in the horizontal direction.   

[drobertson]

I have noticed that same, I have bumped mine too. The one thing I do know is the bearings on mine are running on a threaded shaft, not a fan of this, but it still saws straight and flat, so who knows,

[Dave Shepard]

If the bearings aren't damaged, you can disagree then to take up the slack. This of course affects the alignment, so you'll have to address that, too.

[Magicman]

I whacked mine many years ago.  It needed new "V" rollers and eccentric bolts.  I would pull it completely down and start from scratch with the replacements and then an alignment.

[Delawhere Jack]

You should have no noticeable movement in the guide arm moving it by hand. You must have really smacked it good. I'm with Lynn, tear it down and have a look. Keep your service manual handy. The way those bolts cam around can be a bit of a head scratcher.

[POSTON WIDEHEAD]

A lose guide arm can cause some vibration when sawing.
Knowing you Paul, you may be able to fix it. 

But if were me...ya'll knows I call Woodmizer and get them to send me a new one. 

[Ga Mtn Man]

Well after taking the guide arm off it seems like all four rollers have about the same amount of wiggle.  I took the lower two off and saw that all of the wiggle is in the bearings themselves.  Had a look at another new bearing that I had on hand and it also has some axial movement between the inner and outer races though not as much as the v-roller bearings.  These being radial bearings, I think they need to be loaded to minimize the axial movement and after being smacked around they were no longer as tight as they should be.  There doesn't appear to be any damage to any of the other parts of the arm assembly so tomorrow I'm going to reassemble it, tighten everything up real good and see how it is.  I did go ahead and order some replacement bearings, just in case.  Also had to take my biggest hammer and the MIG welder to the blade guard.  Good times  .

[paul case]

My old saw dropped the head while over a log( chains broke) and whopperjawed my adjustable guide arm all outta whack. It turned out that it only bent the cam bolts and I was able to straighten it all out.

Hopefully yours works out the same.

PC

[terrifictimbersllc]

I think Marty posted a while back a tuneup on the blade guide arm which recognized that the cam bolts don't bend, but instead the holes in the frame will be bent by the pressure on the guide arm, this being when the blade  or arm is lowered onto a log or cant. He had a procedure with a pipe which was effective in straightening out that hole in the housing (or the metal around it).   This restores the ability to adjust the rollers up and down to get them tight in the right alignment.

Don't know about just plain smacking the arm.  My roller assembly has been welded back on to the guide arm twice from that.

ps now I remember I saw somewhere putting a cheater pipe over the cam bolt in place, and pulling down to bend the frame hole down a bit. 

[Magicman]

The eccentric bolts can bend.  The WM tech Bob had to replace mine, but my whacking was much more than lowering the head on a log.  I was returning the head to the front of the sawmill and the guide are contacted the log clamp....at full speed.  The impact knocked the guide arm completely off of the sawmill.   

This happened early in my sawing career and I had plenty of audience.

[MartyParsons]

Hello,
   The bearings do have some play, even when new. They can also be worn. These bearings do not move much and the grease gets well kinda like hard. If I am there I remove the bearing seals with a pick and clean the old grease and smear some new grease in then replace the seals. If it is all rusty in the bearings then replace the bearings. The aluminum pulleys also get some wear. Something also to watch out for on the arm. If the arm was hit the pulleys will dent the steel arm and push metal up on the point where the aluminum pulley rides. I usually take a flat file over the arm where the pulleys wear.

Here are some pictures to help.

This customer had a loose blade guide arm. He put masking tape on the bearing area to tighten it up. Did not work well but got him through the day.
I cant find the picture of a customer who had wrapped the lower rollers with duct tape. It made me smile but it did work, somewhat. I was a mess to get the glue off the rollers.



 

Here is another picture. If the metal is bent that holds the bolt then you need to try this. Put a deep socket over the bolt with all three nuts on.



  

 

Then take a lever and bend the metal that holds the bolt in place.


Note you may not need to bend the metal. Only if you are out of adjustment. Top cam would be down and the bottom cam would be up and the arm is loose or you can not get the adjustment.

I had one yesterday that all that was needed is to adjust the cams.
Last week I bent two bolts trying to get the inside lower area bent to where it could be adjusted. Never seen one quite that bad. The mill had about 7000 hard hours. I ended up heating the metal to get it back. Again this was the first time I needed to do this.

To check to see if adjustment is needed.
   Move the blade guide arm in all the way. Lift up on the blade guide arm. You should not be able to move or turn the lower roller. Move the blade guide arm out all the way lift up on the arm the lower outside roller should not turn.

Hope this helps.

Marty

[Peter Drouin]

I had to do the same thing on my mill Mr Parsons.
I was cutting a log and hit the clamp. Move the arm to the front of the mill.The arm would not tighten up till I bent the steel plate back.

[paul case]

Ya see tis true, DUCT TAPE fixes anything. ;D ;D ;D
PC

[Ga Mtn Man]

Thanks for the input guys.

Marty-- Should I expect the arm to be just as rigid horizontally as it is vertically?

[Kbeitz]

To bad that plate is welded on.
If it had bolts you could drill 4 holes and tap for set screws to use for leveling.

[Rougespear]

Is the blade guide arm weldment solid or hollow tube with caps welded on the end?

[Ga Mtn Man]

Everything's back in good order.  It seems that the play in the bearings was normal...just needed to realign everything and tighten it up good.  The v-rollers have to be very tight to the arm to eliminate all of the side-to-side play inherent in the bearings.  Only took an hour or two, or three, or...  : 

[Magicman]

That's good to hear Paul.  This makes you the "guide arm" expert.   ;D

In my instance, I "cobbled" mine back together for a few weeks and kept sawing until Bob made his rounds with a truckload of spare parts.  I needed new rollers, guide arm chain, as well as eccentric bolts.

[Ga Mtn Man]

Mine only suffered a Standard whack.  Your mill was subjected to a Super whack which is enhanced by a 1HP motor, the weight of a diesel engine, and one-hundred and sumpin pounds of lean, mean sawyer.  :D

[Magicman]

You are too kind.   :D

[MartyParsons]

Hello,
   The arm is a solid square steel. I don't think I ever saw one of these bent. It would take a lot to bend it. The blade guide arm should be tight. As you force or tighten the rollers on the cams the pulleys hold the arm is place. It is possible to tighten the rollers tighter than needed. You will experience the gear roll pin on the motor to shear or the motor will stall and not move. At times I can adjust these in a few min and at times it takes more time that expected.  :-\

If you are frustrated or upset at making this mistake then it would be better attempted the next morning. It is not real hard to do it just takes time a little wisdom. 

Having the blade guide arm adjusted correctly, is priceless. The manual has the adjustment in and out exactly the same. I always adjust the arm 1/32 lower on the inside ( blade guide arm in) The last one I did was 16/32 out and the inside was 17/32 in. The number does not matter.

Hope this helps!

Mr. Parsons