Crowned hickory lumber

kelLOGg · June 09, 2019, 07:01:22 PM

I am sawing an 8' hickory log that is 18" at the small end and 24" at the crotch at the other end. By the time I get to the crotch end there is a pronounced crown in the cut. Need feedback as to what causes this. Here are the particulars:

1) I am using a newly sharpened 4 deg WM double hard band set at 0.025". Hickory is so tough I set and sharpen twice per log. Prior to each setting the set is about 0.022" each side so uneven wear is not a problem.

2) I increased the tension on the band beyond that which I usually use to no avail. Tensioner is a spring so I can't be quantitative here.

3) The beginning of the 18" wide cut there is very little crown but the 24" crotch end has about ¼" crown. I have observed this on hickory logs with no crotch. Apparently when the teeth become dull crown sets in. Since the set is not uneven why does this happen?

4) When I set the teeth I zero the setter with a piece of flat stock before setting each side. I know many sawyers use the raker tooth to zero the setter but I can't be sure the selected raker tooth has not been accidently set by hitting foreign matter in a log so I don't use it.

5) I am sawing live edge and I do not have a de-barker.

6) The guide rollers have minimal wear. Diameter differences front and back of the rollers are 0.000" (stationary) and 0.002" (moveable)

7) Blade alignment was done just before sawing.

(I sawed the crotch just to see what I would get. Pretty disappointing)
Help,
Bob

Small end (little crown)

Crotch end (big crown)

jmouton · June 09, 2019, 07:34:40 PM

i am thinking the hickory is dry and hard as a rock ,and in our experience we use the turbo 7 woodmizer blade for everything and you gotta have a sharp blade to cut dry hickory, the bark is tough on blades and we pretty much max out tension on our lt-40

jim

Southside · June 09, 2019, 07:37:30 PM

Given that crack I am going to say the log has a lot of stress in it and is pulling itself apart, even more now that you have removed some of what was holding it together. Combine that with the twisted grain of Hickory and I don't think you have a sawmill problem.

btulloh · June 09, 2019, 07:55:01 PM

Just another reason to hate hickory. I don't even like to put the chainsaw in it for firewood, much less saw it on the mill.

terrifictimbersllc · June 09, 2019, 09:31:59 PM

Result is consistent with dulling blade, exactly what happens for me as 4s are pushed. Maybe abrasive in crotch seam?

Ps if it is dulling you should be able to see it with a 10x lens and right lighting.

moodnacreek · June 09, 2019, 09:43:20 PM

I think Southside is right. Most hardwood will pull a curve unless you keep the heart centered by taking only one board per side.

Don P · June 09, 2019, 10:15:14 PM

That should have relieved a lot of the stress then, the next pass should be flat or much flatter if it is log stress. If it is crowned every pass in basically the same way I'd look to the mill.

YellowHammer · June 09, 2019, 11:23:00 PM

My first thought when I see consistent crown in real hard wood, pecan and hickory, is dulling, but you seem to be addressing things pretty well, so I'm not sure that's the issue. However, I have dulled and burned bands in one pass in hickory so it can happen that fast.

However, you shouldn't have to sharpen twice per log, normally I can go quite a few hickories between sharpenings. So a few more questions would help me.

Does this happen consistently on many hickory logs or was it just this one?

Normally, once a band deflects that bad, it is getting real hot, and is dull after that cut, so what does the band look like? Does it have pitch build up? What color? What kind of lube are you using? Does the band feel hot if you touch it with your hand? Most times I cut a curve like that, the lube hits the band and steam comes off.

What's your feed rate? My experience with 4's is they cut flat, until they pack sawdust, then they wander. Unfortunately, they have tendency to pack, more so than other bands, so I think they are kind of twitchy. What's the sawdust look like?

It's been my experience when sawing hickory to pull out the stops, I run either cotton picker splindle oil or diesel for my lube.

Anyways, hickory is tough, big hickory is tougher, dry hickory is worse and crotch hickory nasty.

CCCLLC · June 10, 2019, 11:10:43 AM

Agree with Southside, probably spilling some sawdust when you encounter that split as well. Easier said then doing, but sharp blade with increased sawing speed will help. Hickory should never be a guage of your saw or your capability. It is just tough stuff.

MartyParsons · June 10, 2019, 04:07:47 PM

Hello,

Quoteincreased sawing speed will help. Hickory should never be a guage of your saw or your capability. It is just tough stuff.

You will need lots of blade lube, steep hook angle blade ( I prefer 7/39 Turbo) , change blade often. Increase feed rate. If you are getting fine sawdust between the lumber then increase feed rate. Yes move saw faster through the cut!

If you are getting pancake flour between the cuts your blade is getting Hot and it will not cut. Did I talk about lots of blade lube.

watch out for sap build up on the tooth of the blade which decreases the set even more and makes the blade even hotter. The picture is pine sap but Hickory can build up.
Hope this helps.
Marty

kelLOGg · June 10, 2019, 05:00:47 PM

I had a very gratifying morning on my hickory because I did one thing: removed the bark from the entry side on the remainder of yesterday's log! It had begun to peel away so I helped it the rest of the way. (I would have removed it on all logs but it can be like removing plate iron from a battleship.) I did sharpen the band as usual, also. YH is spot on referring to bark as "nasty". I'm amazed how tough it is.

I was also pleased with the accuracy of the cuts (except for one which looks like an operator error) and there was far less crowning. In fact, if I check flatness on each half of the crotch it is flat, suggesting tension being released from the two trunks as several of you suggested. The cut is smooth with few fibers on the surface and sawdust packed about 1/50th (estimate) of an inch on both sides of the cut. I cut the remaining 6 boards and the blade was still clean and cutting well.

I have not cut much hickory. The first was 15 years ago and I don't recall problems. Of the 3 I just finished the problems arose with the crotch.

The band is warm to the touch, never hot. I think this is because I have crowned steel wheels which conduct heat very well. I use diesel lube applied via felt pads top and bottom of band. The band finished the cuts very clean. On earlier cuts on this hickory the teeth were burnished with hard material which I had to remove with a rotary steel brush. Concerning feed rate: I didn't measure it but I estimate it took about a minute to cut thru 8'. At times during the cut the feed rate would just stop and I would assist with very slight push from my hand. I have speed control but dialing it up or down is a slower response than a slight push from my hand. A faster cutting speed would kill the engine. The rpm dropped to about 3200 at times so I slow down to get it at least to 3400. Notice my HP is only 16. Most sawyers with hydraulic mills have 30+ HP. I'm in the little league.

All feedback has been very helpful - thanks to all.

See pics.

Bob

2nd board from top is a little thin - my bad

Example of crotch cut

Band very clean after cut

Lumber racked up to dry

Very slight crown

Nice cathedral grain

Nice straight cuts thru NO BARK

Blade oiler

alan gage · June 10, 2019, 05:19:04 PM

Quote from: kelLOGg on June 10, 2019, 05:00:47 PM
A faster cutting speed would kill the engine. The rpm dropped to about 3200 at times so I slow down to get it at least to 3400. Notice my HP is only 16.

Glad to hear you got it sawn up ok. I've seen recommendations to increase feed speed on species like ash when the sawdust is very fine and wants to pack in the cut. But like you I can only increase it to a certain point and then the engine really starts to bog down. So I guess we do what we can. So far it hasn't been a big issue for me.
Alan

CCCLLC · June 10, 2019, 05:22:09 PM

I think that cambium layer under the bark is kin to Kevlar.

kelLOGg · June 11, 2019, 06:11:50 AM

:D Yeah, they went to a lot of effort to make Kevlar when all they had to do was use hickory bark. ;D

Weekend_Sawyer · June 14, 2019, 12:03:19 PM

I like your tie down method.

Let us know how it dries.

kelLOGg · August 18, 2019, 09:21:09 AM

Weekend_Sawyer,

It's drying pretty fast. I inserted my pin meter about mid way into the wood shortly after I stacked the lumber and the MC read about 24% which I thought was pretty low for newly sawn hickory even though it was dead when felled. After about a week the MC began to fall a per cent a day - again pretty fast and stopped at 12% - as low as air dried gets in my area. Now it is awaiting its turn in the kiln. I took the ratchet straps off and the lumber remained flat. If I had anticipated such a low initial MC reading I could have put it in the kiln right after sawing but it was probably better to let the MC get uniform throughout the stack first.

RobS · August 18, 2019, 02:50:16 PM

Back in the day...

We normally sawed 18-24,000 bft per day with most any hardwoods. A hickory day would end up 12-14,000 bft.

First issue is the debarker could not keep up with the headsaw. Bark would wrap around the debarker head line barb wire. This would stall the head, smoke the belts, plug the rollers and barn cleaner. We used the log truck loaders to peel the bark off the logs in the log yard and feed some pre-de-barked logs to the mill to help the debarker try to keep up.

Then the headsaw would have to stop to sharpen 5-6 times through the day, compared to 1-2 times on any other hardwood. The logs would pop open in the middle of a cut. The saw blade heat up and loose tension sometimes also. Like hot enough you can't touch it with a bare hand.

Cants sent to the edge would pop, split, and drop wedges while running through the gang saws. Dull and heat the saws too. So expected to have to change out the set of 10 saw blades in the edger atleast once in the day.

Nobody like to see the note in the office in the morning calling for hickory to be cut.

moodnacreek · August 18, 2019, 05:30:24 PM

Fresh cut, kept wet logs are a beautiful thing. You can almost never cut them soon enough. So many think logs should be kept dry.

KEC · August 18, 2019, 06:19:01 PM

I know you guys are right about how tough hickory bark is. But, earlier this summer a cut up a small Bitternut Hickory for firewood. I scored the bark several times the length of it with the chainsaw and was able to remove all the strips of bark with a camp axe. The resulting stovewood was top shelf, wish I had more of it. All the bark was left in the woods to go back in the soil.