Troubles sawing 20' on my LT40

barbender · April 09, 2014, 11:01:49 PM

I have been sawing some 20' Bur Oak for trailer decking (on an LT40), I am having trouble with how much the cant hangs over the bed supports on each end. It is causing me some "thick and thin" problems, whether I keep flipping the cant 180, or saw the cant straight through. It seems there is just too much hanging past the bed supports so the ends of the board droops down, Does anyone have any techniques for dealing with this?

VictorH · April 09, 2014, 11:08:02 PM

I've had this happen - but there are some things that you can do to help - first make sure the last bunk is even with the rest, if it's low you will always have a thick end. I've seen how a couple of guys will clamp, strap or even sit on the cant to keep the middle from raising up which can help keep the end from sagging. My Lt40 can cut 20' and pretty much support the whole cant - just how long of decking are you cutting?

highleadtimber16 · April 09, 2014, 11:09:15 PM

I have the same problem as well. I vary rarely cut 20's though. If I do they're 6x12's so they don't sag more than an 1/8th. I'm looking at getting an extension which would obviously fix the sagging problem. There is probably a cheaper fix if you don't need an extension. Someone will have a solution. Good luck!

Magicman · April 09, 2014, 11:10:41 PM

I am surprised that the movable supports don't support the cant ends well enough. I suppose that a proper height block could be placed on the angled support??

backwoods sawyer · April 10, 2014, 02:17:47 AM

Two things. Always make sure the movable bed rails are swung around to suport as much length of the cant as they can and when clamping give the clamp a bump down this insures the cant is sucked down and not humped up.

customsawyer · April 10, 2014, 03:51:14 AM

Another trick is to leave the last few boards on top of the cant so they will hold down the last few. You still have to make sure the moveable bed rails are swung out to support the last board.

Chuck White · April 10, 2014, 07:15:33 AM

Agreed, swing the rear bunk as far to the rear as you can and still be under the cant with it.

Swing the forward bunk as far toward the hitch as you can and still be under the cant with it!

Of course make sure the movable bunks are level with the main ones!

barbender · April 10, 2014, 09:31:59 AM

The decking I am sawing is right at 20', and I have tried pretty much everything you fellas have suggested. What I haven't tried is swinging the end supports around, I've been leaving them parrelell to the other supports. I'll try that today. I am thinking I may be dealing with a combination of sag and some stress in the logs. I hate messing up on these, it is hard to get ahold of big bur oak up in my country. BTW, full dimension 20' bur oak 2x10's are HEAVY! :D

Magicman · April 10, 2014, 11:09:21 AM

I constantly swing the movable rails around and center the ends under cants no matter what the length. I always tell the customer or helper to keep watch and if I fail to move them, to stop me for a reminder. Supporting the cant ends is very important. You can also look and see if the ends have raised up and the cant needs flipping 180°.

Jim_Rogers · April 10, 2014, 12:03:51 PM

If you get one with a thick end, you may have to slide it back to the first regular end bed-rail and reclamp it and trim the thick spot off.
Of course that means if one has a thick end then one or more may have a thin end.
Don't ask me how I know. ;D

Peter Drouin · April 10, 2014, 12:22:26 PM

When I cut decking never over 8" wide most times 6", the ten will cup.

Jim H · April 10, 2014, 09:59:09 PM

It seems like I remember someone installing the older style moveable bunks from an early '90s lt40 on each end of a newer mill to support the long stuff. Swinging the moveable bunks has always worked for me.

barbender · April 10, 2014, 10:52:39 PM

Quote from: Peter Drouin on April 10, 2014, 12:22:26 PM
When I cut decking never over 8" wide most times 6", the ten will cup.

Peter, I don't doubt that a bit. But 10" was what they wanted. Actually 10",8", and 6" widths in both 2" and 1 1/2" thicknesses. I'm thinking swinging my supports out farther will do the trick for my thickness issues. I knew the answer was likely right in front of me, I just needed someone to point it out ;)

highleadtimber16 · April 10, 2014, 11:38:17 PM

I figured you were already swinging the rails out to support the end ;) You're very right, the answer is sometimes right in front of our faces :D I still find they don't have enough reach. Hope it goes well.

drobertson · April 11, 2014, 10:44:16 PM

I have often used Kant-twist clamps to keep the swing rails where I want them. Turning the log will often times move them, causing someone to have to re-adjust them. Often I will keep them out of the way for the first two face cuts, then clamp them into position. Keeping most of the cant in contact is the bench mark for keeping up with bowing of the cant. Then adjust sawing as required. sounds easy don't it?

barbender · April 12, 2014, 12:08:26 AM

Sounds easy, but my back is telling me otherwise :D I'm learning other things, like my board drawback doesn't reach the end of the log. No biggie, but it totally changes the material flow.

backwoods sawyer · April 12, 2014, 01:16:40 AM

Today Little Jo was sawing a few 20'+ and the bumper was keeping the saw against the cant on the way down to the next set and she was having to bounce against the bumper as the saw was setting to keep it from binding and pulling the board back enough so the saw could raise. Cutting at the limits does have it's challenges ;D