Long Length Sycamore Tips ?

Warren · April 29, 2007, 10:44:29 PM

Added a 12 ft extension to my mill last week. Had a customer drop off a 24 ft sycamore to saw out 2x12's for a barn yesterday. Any tips or tricks to sawing longer lengths of sycamore ?

Also, he said a "crown" was O.K. to allow for settling/bending across a 24 ft span. Anyone ever intentionally saw lumber such that it had slight bow or arch in one direction ? If so, how ? I thought about putting shim blocks under both ends of a 3 sided cant before sawing the 4th face. Then rotateng 90 deg. to slice off the 2x's with a bulge/crown in the middle...

As always, all help greatfully appreciated...

Warren

WH_Conley · April 29, 2007, 11:01:39 PM

Warren, I have never sawed sickeymore that long, but if it behaves like other wood, if you want a crown, just take more sapwood off one side than the other. The side with the most sap will pull that direction.

As a disclaimer, everytime I think I have something figured out, something goes wrong. ;D

solodan · April 29, 2007, 11:16:39 PM

Something just doesn't sound right. A 2x12 just doesn't seem large enough to span 24' and take a vertical load, which is the only reason you would need a crown. If the beam is to be used as a collar tie, then I would not see it necessary to leave a crown. Maybe just sawing them out regular would be best, depending on what the board is to be used for. I would also guess that at 24' you would have a slight crown anyway, and he could just turn the crown up.

Hopefully one of the guys here that know more about engineering here will chime in.

DWM II · April 30, 2007, 07:09:42 AM

I found that when I saw a log with a bow in it that when I saw out the bow first to get the flat dimension that I want the boards will naturally crown as they come off the cant. I learned this as I did the opposite and watched the boards bow as they came off.
Now this wont work with a straight log, I'd rather have straight ones any day. ;). But it aint a perfect world either.

Now that is dealing with pine---I dont know how sycamore will react, its got a interweaved grain I belive and may react different.

metalspinner · April 30, 2007, 07:29:41 AM

Everyone of my quartersawn oak boards has a crown in it. If the boards are QS that crown will show up all by itself. ;)

treebucker · April 30, 2007, 09:18:15 AM

Quote from: metalspinner on April 30, 2007, 07:29:41 AM
Everyone of my quartersawn oak boards has a crown in it. If the boards are QS that crown will show up all by itself. ;)

That's how I would try to achieve it. But because of it's interlocked grain, and the fact that stress is common in sycamore, it's going to be hard to predict what's going to happen on cuts that long. Hopefully you've got some extra logs to play with.

Warren · April 30, 2007, 10:26:20 PM

Thanks guys. I think I'll just saw 'em out and see what happens. If they end up with a little crown, I'll just smile... ;D ;D ;D

Warren

Warren · May 04, 2007, 05:45:05 PM

Quick follow up. WH gets a tip o' the hat for the practical approach to "crowning" the longer pieces of sycamore. The tree had a little sweep to it, so I just took a little more off'n one side while squaring it up. Customer pulled in just as we were putting the biggest log on the mill. Left an hour later very pleased with his 24ft 2x12's with the "crown" on them....

Learned something else in the process. Put one of my freshly resharpened blades on the mill before I started. When I started taking the flare off the log, I noticed the sycamore cut a lot easier than oak, so I cranked up the feed rate. On the second cleanup cut, the blade started to "trough" or dive in the middle pretty significantly (18" to 20" wide cut). I figured I had screwed up the blade during sharpening and setting. Pulled it off and put another one of my resharpened blades on. Noticed the same thing. But, when I slowed down the feed rate, everything leveled out and cut cleanly.

I am using a 0.055" blade with 10 deg hook and resetting to 0.023" to 0.025" set. Should I be using a blade with a steeper hook angle and more set to allow faster feed rates in soft sycamore, kinda like pine ? Or, (against my will) just slow down ?

This is my first experience with sycamore. Saws easy enough. Just want to go a little faster.

Warren

Fla._Deadheader · May 04, 2007, 06:05:48 PM

Blade tension changing ??? When we were sawing wide Cypress, we would jack a little more tension in the blade. It worked well. ??? Don't ask how much, we just used the "Grunt" method.

WH_Conley · May 04, 2007, 08:42:20 PM

Warren, I would think that is because of so much dust in the gullett.

Other side of the same coin, get a cant squared up and the butt will cut different than the trunk ??? ??? ???

Greg Cook · April 15, 2008, 10:58:15 PM

Warren, I wanted to bump this one back up to the top and find out how those 24' 2x12's are looking almost a year later. Is that customer near enough that you have seen them in the barn? I am going to need some 20' 2x12's and was going to use poplar, but all the loggers around here tell me they can't find any that are long-straight-large enough. Maybe they don't want to bother with extra long stuff, but my part of the state has been kept pretty well logged over the years.

Anyhow, did you ever see those Sycamore 2x12's again?

fencerowphil (Phil L.) · April 15, 2008, 11:02:58 PM

My little experience with Sycamore says, "use another wood" for long structural members,
so I am also interested in what happened with them.

WDH · April 16, 2008, 06:52:07 PM

With sycamore, they will probably tend to twist.

Warren · April 16, 2008, 09:41:00 PM

Greg,

I have seen them since they were put up, and they are doing fine. The fellow I cut them for is a barn builder and a farmer. For about a 30 year period, he and his crews probably built better'n half the tobacco barns in the county. i would reckon he had a good idea what he was working with before he asked.

He is in his early 70's. He and his wife put up about 10,000 square bales of straw each year. Never touch a bale. After he combines the wheat, he sets her up on a baler with an accumulator table. Drops 9 or 10 bales in a bundle. He comes along with a bobcat with a hook/claw gizzie on the front that picks up each bundle and takes it to the stacking shed.

His stacking shed for the straw bales originally had 12 ft bents. Made it a little tight for the skid steer. He put the 24 ft 2x12's up in the top and took out every other post to make 24 ft bents.

Warren

P.S. Funny story. His wife went with us on the church mission trip last summer. She woke up at 4:00am the first day. At 5:00am she was asking her daughter if everyone was going to sleep all day ! ;D ;D ;D