Sawing frozen wood

dirtmover2 · January 05, 2022, 07:57:20 AM

Hi, I'm new to the forum although I've used it numerous times in the past for various topics. I rebuilt a circle mill and have been sawing some for a couple years now. I need some advice on sawing frozen or rather partly frozen wood. I'm in the northern climate, right across the border from Maine in New Brunswick, Canada. I'm cutting tamarack, fir, and white pine right now and as soon as it started freezing the saw started running out. It'll run out 1/4" as much as 1/2" on 12' cutting first and second slab which results in a tapered or parallelogram shaped cant. Not good for the blade tho. Soon as I get into the unfrozen wood or slice the cant into boards it cuts as straight as an arrow. Saw is a 48" 40 F style teeth 9/32 HSS bits running at 800rpm with JD 4045 engine @95hp. I've had the blade hammered to straighten it as it was tensioned incorrectly when I started. I've adjusted lead out to 1/16"+ during the summer to prevent blade heating and saw straight in softwood. Any advice to make winter sawing better? Should I switch to standall bits? Is it worth replacing the shanks? Mine are wore some but not really bad. Anything else I can try? Thanks for any input.

moodnacreek · January 05, 2022, 08:36:15 AM

You could put in stand-all's and it will help. Also file your shanks to get a rough square edge to hold more sawdust. And then there are 'frost' shanks, That could change the saw so it needs to be hammered. You could try it by adding the new shanks gradually, like every fourth shank and see what happens. With 'frost' or winter shanks you run regular bits so this saves $. Don't use long bits in winter, actually short, perfectly sharpened bits are best in frost. The problem is the frozen sap outside the log as you mention in saying the [heart] boards saw well.

dirtmover2 · January 05, 2022, 06:55:35 PM

ok thanks, I'll have to try that. How wide do the shanks need to be or is the square edge sufficient? Am I going to lose some tension in the shank by filing them square? Also, would narrower bits be better or stick with 9/32? Had an old sawyer suggest grinding back every other tooth to coarsen up the sawdust and take less power, thots?

moodnacreek · January 05, 2022, 08:50:53 PM

If you think you have to go too far filing the shanks, just make the throat or gullet rough. If you want to do every other tooth just replace every other one with longer new. You could buy 17/64 but 9/32 will get narrow with filing. The every other tooth trick will be a problem in knots as the teeth are too far apart and the saw will try to saw around hard spots but you can try it and see. It will give more power. In time I think winter shanks and chrome regular bits would be the way to go but both the bits and shanks are expensive these days. What make sawmill is that? I see it has a board roll.

Ron Wenrich · January 06, 2022, 05:17:16 AM

I used winter shanks and regular bits all year long. Most guys in my area do that. The problem with partially frozen wood is that sawdust will cake unto the log. You're sawing 2 types of wood in the same log. Miscut lumber and heated saws are usually the outcome. We always just shut down for a few days and allowed the logs to freeze the whole way. Cutting back the lead also tends to help the problem.

Usually, by the time its figured out, its spring, the logs are partially thawed (causing more problems), and your hair will start growing back. ;)

moodnacreek · January 06, 2022, 09:01:22 AM

Same here, winter shanks, regular length bits. North of here it's all stand alls / carbide, and they are stand all. The stand all style take more power and cost more but sometimes they are needed. I had a style 3 saw that would not cut anything without them. One drawback of the winter shank is that you can't really use carbide. One saw I had needed 3/16" lead. That was because it had a round lump like a doughnut in the center area. Needing 3/8"? I didnt know things could be like that and the saw be made to go.

dirtmover2 · January 06, 2022, 08:11:18 PM

I'm not sure of the make. I got it out of an old barn, was kinda built in with wood beams and wood husk. I salvaged what I could and rebuilt it all with steel beams. Next project after a roof is sawdust carrier and rebuild the carriage with steel and possibly lengthen it to accommodate 24' logs. I've got 95 hp on it now, some fellas have told me I should have 3 times that minimum. Have looked at putting a 6-71 Detroit on but whats the scoop on hp? Cant have too much I guess so where is a good balance for power?

moodnacreek · January 06, 2022, 09:31:00 PM

They all say that about power, how much do they have and what are they sawing? For softwood and that size saw you have plenty and a 6-71 would be nice but really over kill and you have to buy fuel.

dgdrls · January 06, 2022, 10:23:18 PM

Welcome to the FF,
Partially frozen logs are the worst.
Narrower bits would help
and as others pointed out winter shanks.
You can also take some cold days off and let the logs freeze thru

FWIW, IMHO I think your saw speed is too fast
48" saw at 800 RPM puts you in the 10,000 surface feet/minute range.
I understand 8000 surface feet per minute is a good compromise
for both winter and summer sawing.

D

moodnacreek · January 07, 2022, 09:11:37 AM

Dgdrls is right, a fast saw makes fine dust that spills and freezes to the kerf and puts the saw off line. You may read here the band saw guys talking about the frost notch. That is to hold the fine frozen sawdust until it is swept out of the kerf. The stand all or winter shank is no different, The coarse sawdust from a slow feed stays in the gullet better. Faster feed also makes coarse dust, if you can do it.

dirtmover2 · January 09, 2022, 12:42:18 PM

ok so slowing blade speed may help for winter, I thot it was critical to run it at the speed it was hammered for but it seems to run straight from 500rpm up. I set up the mill for 700rpm but the guy that tensioned my blade said I should run it 800. Its easy to slow it some with the diesel but I lose a bit of power also. I may try adjusting governor and see if it'll respond faster to the load. I'd think that would be the advantage of a detroit is faster load response but this is based on speculation and not experience, yet...

dirtmover2 · January 09, 2022, 08:17:09 PM

Also a question on sharpening. Having trouble cutting teeth without turning em blue which softens the edge. Got a 6" stone running about 2500rpm and I just put light pressure on tooth for a moment a couple times in a row and the tooth is heating. Is there a problem with my stone or what am I doing wrong?

moodnacreek · January 09, 2022, 08:37:31 PM

Need to know what you sharpen with. If you keep the teeth sharp and don't hit anything just a touch [with a jockey style] is all you would do. Almost doing that before it is needed. 800rpm is really wheeling and I say way too fast. there is an issue here and I will take a chance and say: [I think] hammering a saw for low rpm can be a lot of work for the man doing it. They get the saw flat and the tension where they want it and equal all around. Now if there is too much tension the saw will not run slow, so they hammer around the rim to pull the tension and it screws up all the work they have done so if you run fast the hammering job is much easier. Just shooting from the hip.

Ron Wenrich · January 10, 2022, 06:17:44 AM

If you're turning your teeth blue, you have either too hard of a stone, or you're too aggressive. The only thing I used my Jockey grinder for was to keep the angle on the teeth in pretty good shape. When hand filing, I have a tendency to get it a little too fat. But, when I was done using the grinder, I would dress it up with a hand file. I used the hand file more than a grinder.

I ran a 54" at 700 RPM and I needed to be on top of sharpness, lead, saw guides, belt tightness and anything else that affects the saw. Rim speed on that saw was 113 mph. Your rim speed for the 48" saw at 800 RPM is 114 mph, so you're in the ballpark of what I was running.

Most of the older mills that I've been around run at 540 RPM and most used a 56" saw. That put the rim speed at about 90 mph. That comes out to about 630 RPM for the 48" saw. I don't know if that will make a difference in how the saw will stand being hammered for a much higher RPM.

Having logs completely frozen should make a difference.

dirtmover2 · January 10, 2022, 07:13:42 AM

I dont know the grit of my stone, had it given to me by my saw guy. Any suggestions where to order the right one? Any manuals or saw guys I've talked to suggest 9000-10,000 ft/min rim speed and maybe 8000 for frozen. 800rpm is right at 10,000 so I,ll try slowing it for winter at least. Softwood in summer sawed perfect at that speed.

Ron Wenrich · January 10, 2022, 08:26:22 AM

Menominee Saw (sponsor on the left side of this page) deals in circle saws and supplies. There are 3 colors, if I recall, grey, red and white. I think red is the hardest. You also need to dress the wheel every once in awhile with a dressing stone to keep it in goods shape. The wheel gets a groove in it from use. The harder the stone, the easier it is to burn the teeth.