Jerky feed rate

WH_Conley · December 17, 2008, 05:56:30 PM

Having a feed problem on my 97 LT40HDG24. Just started a couple of days ago would hesitate then restart in the cut. Well you know what happens when one starts instantly, the cuts look like a washboard. Have not made it in the house in time to call WM, think I need one more new part. In the last couple of days I have replaced both bearings on the sprocket shaft, all 9 cam follower bearings and swapped the motor out. Chain is well oiled with ATF. Nothing out of adjustment allowing anything to contact the rail. I keep rail well painted so if anything rubs I will have a shinny spot. Did note some wear on the sprocket teeth. Anybody have any idea I may have missed?

Bodger · December 17, 2008, 06:28:49 PM

Mine is a 95 so I don't know if they're the same but it sounds like an electrical problem...could be a bad speed control (reostat) or a loose wire from the speed control. It goes into a little junction box in the back of the control box and there are some little bitty screws that should hold it in. If one of those has worked loose you'll need to take the back of the box off and tighten it. The reostat speed control should be available locally at quite a savings over the factory price and you'll save shipping. Try an electrical supply house.

WH_Conley · December 17, 2008, 06:45:25 PM

Replaced the rheostst before, cheaper at WM than local. Don't hardly beleive it is electrical, does it at about the same places every time.

Pineneedle · December 17, 2008, 06:55:33 PM

I had the same problem with my 2005 LT-40 and after taking everything apart and spending alot of time on the phone with Wood-mizer it turned out to be a loose belt on the feed motor.

Tom · December 17, 2008, 07:01:01 PM

Something that is the last to look for and the first to give trouble is a piece of splinter, or some foreign material hidden in the bottom of the mast. It can "wedge" the chain or the frame, or the rollers, or the button that rides the rail.

A travel chain that is stretched too tight might cause it too.

If it is in the same place, I would look for foreign material, especially around the axle area.

Believe it or not, a dull blade can cause it too. The head builds enough pressure to force the head to cut and then the blade quits when the pressure is lessened. Nothing happens until the pressure builds again. That would be rythmic though.

WH_Conley · December 17, 2008, 07:26:21 PM

Might feed perfectly smooth for a couple of cuts, then the next 1, maybe 5 cuts it does the jerky thing. Checked belys and foreign material. At 3000+ hours on this mill I thought I had seen everything it could do. Guess not. >:(

DWM II · December 17, 2008, 07:34:58 PM

Check the contact points on your drum switches. Mine had some green corrosion causing a similar problem. It would be a good opportunity to re-lubricate them with a dielectric lube.

MartyParsons · December 17, 2008, 07:55:23 PM

Remove the belt from the Pulley on the feed motor assmebly. Push the saw to end and back does it bind? In the same place where it stops when you are sawing? Lower track assembly has either stop bolts on the new mills or weld mounts on the older LT40 series are they adjusted correctly? Remove the feed control knob and spray the pot with WD 40 and see if the dead area stops. It will come back but it might show you the problem and you will need a new feed rate control ( Pot ) There are many different types of Pot available with different quality levels.
While you have the Forward feed belt removed Put the Drum Switch in Forward position turn Pot and see if the Power feed motor changes speed when pushing the pot up down or moving slowly from low to high range. In 1996 the original power feed has lights on the board if you have you manual it should tell you what each light is for. You may have changes the board to the newer version if it failed and the lights are easier to read. The In light will change brightness with the pot or the veriable feed control. Also check you contacts like DWM II said on the drum switch.
M

pineywoods · December 17, 2008, 08:22:18 PM

Had the same problem with my 95 model. Corroded splice in wire between the control head and feed motor. here's how I isolated it. Hook a dc voltmeter to the 2 leads going to the feed motor. Saw. Watch the meter. If it stays the same, you have a mechanical problem, if it drops, electrical. My bet is on electrical.

backwoods sawyer · December 18, 2008, 02:14:40 AM

Relevel the mill with the tires off the ground, and loosen the leading bearing on the underside of the carriage about a quarter turn. Woodmizer had me change out the feed rate switch half a dozen times before they got off the electrical kick and finally listened to what was happening with my mill. The rail has a crown to it and unless you get the weight off both tires, it creates a point where the carriage binds up on the rail. Since you have changed all the bearings, it is possible to have the bearing to tight. Use the lower rear bearing to level the head and then snug the front bearing up and back it off a quarter turn to a half turn then tighten the bolts to hold it in place after all the adjustments are done.

WH_Conley · December 19, 2008, 03:35:44 PM

Appears to have been the "Pot". The WD40 didn't work, but I had another one that I switched out. Still can't figure why it just did it a couple of places on the track. Took belt off and made a dozen trips from one end to the other and cpuld not feel any resistance. No foreign objects, nothing. Thanks guys.

MikeON · December 22, 2008, 12:16:49 PM

I've had problems like this when a little ice or frozen sawdust builds up on the rail. It doesn't take much.

ohsoloco · December 23, 2008, 10:05:09 AM

I typically feed it as fast as I can chew and swallow it until it is gone.....oh, I think you're talking about something else :D

WoodMiller · January 04, 2009, 10:17:51 AM

I know this is a late reply, but don't forget that the bottom guide rail on the LT40 can corrode/gum up too. You can't see the rail unless you get under the mill, but if the hesitation is at the same spot(s) each time and you've checked the top rail, chain and mast, clean the bottom rail with a little ATF and a 3M pad. Might work. :

WH_Conley · January 04, 2009, 10:38:14 AM

Since replacing the "pot", no problems.

DanG · January 04, 2009, 01:35:04 PM

Quote from: ohsoloco on December 23, 2008, 10:05:09 AM
I typically feed it as fast as I can chew and swallow it until it is gone.....oh, I think you're talking about something else :D

I've been resisting this thread and its enticing title until I couldn't stand it anymore! I finally caved in and find that Ohso has already succumbed to the inevitable. :D :D :D

Just for the record, my jerky feed rate is somewhat inhibited by the condition of my teeth, and is nowhere near what it once was. :-\

Dave Shepard · January 04, 2009, 01:48:32 PM

:D :D :D

One other thing to look into regarding feed rate issues is the connector in the battery box for the feed motor. On the '92 mill, it corroded, and the resulting voltage drop burned out the windings in the motor. The new motor is at least twice as fast as the original, which had 0 hours on it since new. (It was used as re-saw only).

Meadows Miller · January 07, 2009, 07:55:02 AM

Quote from: DanG on January 04, 2009, 01:35:04 PM
Quote from: ohsoloco on December 23, 2008, 10:05:09 AM
I typically feed it as fast as I can chew and swallow it until it is gone.....oh, I think you're talking about something else :D

I've been resisting this thread and its enticing title until I couldn't stand it anymore! I finally caved in and find that Ohso has already succumbed to the inevitable. :D :D :D

Just for the record, my jerky feed rate is somewhat inhibited by the condition of my teeth, and is nowhere near what it once was. :-\

Gday

It Was Asking for it from day One ;) Dang and Ohsoloco ;) :D :D :D ;D Fror the record my Jerky feed rate is Pretty Dang FAST ;) :D :D :D ;D

Chris

backwoods sawyer · January 08, 2009, 05:49:30 PM

Another problem that can affect the feed is a stiff link in the chain. I got two chains so I pull the chain off ever so often and roll it up in bucket of oil and tuck it under the work bench, and put the other one that has been soaking for a couple months on. That way I know it is getting oil into all the little tight spots. I like to put some fresh oil on that chain every time a run the mill and some times when it is just sitting. I keep a spare for the up down chain and the guide arm the same way.

kelLOGg · January 08, 2009, 06:14:31 PM

As a 4-poster owner I thought I would chime in. When I added my chain drive, Cook advised to be prepared to drive it from both sides because when sawing wide boards with a single side drive the drive side tends to lead in the cut and the opposite side follows. I found this to be true - got a funny saw mark pattern. I added a 2nd drive chain on the opposite side and have not had a problem since. Just my $0.02 cents worth.

Bob