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Woodmizer LT40HD carrage, up/down motor speed control?

Started by janc, October 13, 2018, 06:44:46 PM

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janc

I have trouble getting the up/down function on my older Woodmizer to stop exactly where I want it to, usually takes 2 to 4 tries to get it just right.
Is there any way to add on a speed control to this function, or manual fine adjust as well as the motor?
Most of the wood I cut is high value material, so being off a little is not a good thing.
The mill is properly adjusted and cuts very well once set.

Thanks

Stephen1

I usually have to bump up or else the head will drop a 1/16 while sawing. I believe it has something to do with the friction pads. 
Lets see what other ideas are out there
IDRY Vacum Kiln, LT40HDWide, BMS250 sharpener/setter 742b Bobcat, TCM forklift, Sthil 026,038, 461. 1952 TEA Fergusan Tractor

janc

Quote from: Stephen1 on October 13, 2018, 07:26:05 PM
I usually have to bump up or else the head will drop a 1/16 while sawing. I believe it has something to do with the friction pads.
Lets see what other ideas are out there
I should have noted, I am always setting on up movement for that reason as well.

Magicman

Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

GAB

Quote from: Magicman on October 13, 2018, 08:00:32 PM
I have never had any downward creep as I saw.
I do not have downward creep if I am using the Autodown or Pattern mode.
If I am setting for a particular height, I always set going down and stop 1/32" above the desired thickness, and strart the blade at least a foot before sawing and it will most likely be at the desired height when the blade gets to the wood.
My mill has creep I just have to live with it.
Gerald
W-M LT40HDD34, SLR, JD 420, JD 950w/loader and Woods backhoe, V3507 Fransguard winch, Cordwood Saw, 18' flat bed trailer, and other toys.

pineywoods

On my manual mill I have better luck doing like the setworks option. Deliberately dropping 1/8 -1/4 below the desired spot, then bumping upward, it's much easier to stop on the target when moving upward.
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

janc

My current idea, is to add on a speed controller to the lift circuit, like on the carriage feed, along with a momentary push button switch. The push button would disconnect the regular circuit and connect the speed controller.
Downward creep is not a problem, it just takes a few tries to get it on the mark.

beav

On my 87 lt40  the pulley on the up/down gearbox is exposed on the top rim so you can manually turn it a bit with an open hand. The technique I've used for decades: raise head to 1/16 or so below desired height. Engage clutch. Manually pull back on pulley until exact height is reached. Cut. It happens fast. Not sure what year that pulley got buried.
It wasn't a compromised pulley guard, that's how we did it way back then before setworks and stuff

MartyParsons

Hello Janc,
 Can you tell us what year mill you have? Engine size. Setworks or Accuset on just manual control for up down. How many hours do you have on the mill?
Thanks
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

janc

Quote from: MartyParsons on October 14, 2018, 08:07:36 AM
Hello Janc,
Can you tell us what year mill you have? Engine size. Setworks or Accuset on just manual control for up down. How many hours do you have on the mill?
Thanks
Marty
Marty,
I think my mill is about a 1992 model, I have had it for about 10 years, it's old, but in good shape, lots of updates, new bearings, etc. it has the Onan P224 engine, I have the Set Works module, but no encoder and it's not hooked up, so really just manual. Meter shows 1735 hrs, could be correct? lots of accessories, bed extension, sharpener, resaw.
 

MartyParsons

Hello,
  Like the other members. I would go past the mark and bump up. It takes a little practice to get every cut to be exact as you are wanting. I would adjust the mast pads close at the top. The manual says thickness of a credit card. I would go a little more close. The tubes are wider in the center where the pads ride and I bet it is not common to be sawing at 35" from the bed. I always jerk the saw back to see if the height changes that little bit. We are talking about the half thickness of the line but in your case that may not be close enough.
Hope this helps.
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

janc

So what I did, was to wire a speed controller into the up/down motor circuit. It took a speed controller assembly, four automotive relays and a small momentary push button switch, total cost of new parts, about $25.
When I push the button, it disconnects the up/down drum switch, connects the speed controller, powers it up and instantly starts it moving.

It works great, drop the head down with the drum switch using right hand, operate button with left, easy to stop right on the line, and quick.

Ben Cut-wright

Quote from: janc on October 25, 2018, 09:45:16 PM
So what I did, was to wire a speed controller into the up/down motor circuit. It took a speed controller assembly, four automotive relays and a small momentary push button switch, total cost of new parts, about $25.
When I push the button, it disconnects the up/down drum switch, connects the speed controller, powers it up and instantly starts it moving.

It works great, drop the head down with the drum switch using right hand, operate button with left, easy to stop right on the line, and quick.
That sure is a cheap enough modification.  I am able to fine adjust that last partial turn often needed via the exposed vee belt pulley on my old LT40. Experience allows me to get very close to the mark without "bumping" the switch.  I try very hard to move the drum switch to full contact when operating the lift motor, no bumping.

Starting amperage on the lift motor is the most amperage/load it sees, so the less starts, the longer it lasts.  Your added "speed controller assembly" should lessen startup amperage?
 
Parts list, wiring diagram, and pictures would certainly benefit others who may wish to utilize that assembly. 

janc

Here is a photo of the device sitting on top of the mill control box, assembled for testing, and links to the components, these components are available from many sources.
As noted by
Ben Cut-wright, 12VDC is hard on the switches, so I sized the capacity of the controller and relays much larger than the nameplate amperage on the motor. I don't know how long the relays will last, but they have made literally billions of these, and they are many in every vehicle in the world and rarely fail, so I am hopeful. I did wire it up so the speed controller connects at the same time power is applied, so it may close the relays a fraction of a second before power is flowing, and there may be lower starting current as well, which would help, will have test to find out.

I will post a wiring diagram  and more photos when the device is mounted in a box.

 

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