Sharpening Bands to Cut Spruce

Gere Flewelling · August 20, 2023, 01:52:17 PM

I have a customer that saws a lot of spruce. He has been having issues with waving cuts around knots. I have sharpened a few of his bands that still give him similar results. The bands I sharpened were 8 degrees and I set them between.025-.029 prior to sharpening with my drag type sharpener. Once set, I always go light on sharpening, but am sure I reduce the set some during the process. I have never sawn spruce personally but have heard that their knots are very hard. I am wondering if I reduced the set somewhat ,if it might cause the individual left and right teeth to have less pull to one side or the other when hitting a hard knot. Thus to help reduce the tendency to wave. I am curious what others might have found in their saw sharpening experience. Advise would be appreciated.

ladylake · August 20, 2023, 02:06:49 PM

I find that 4° with a heavy set and shallow gullet do the best in spruce, still not perfect in wide cuts. Steve

WV Sawmiller · August 20, 2023, 02:30:21 PM

I'm with LadyLake on the 4 degree blades. I seldom saw over about 12" diameter Norway Spruce . The knots are hard but I get decent results from them.

Bruno of NH · August 20, 2023, 02:48:38 PM

I have good luck sawing fresh spruce with turbo 7's the same set I use in pine.
But when it's set around for a bit I use a chip sweep type band with great success.

barbender · August 20, 2023, 08:42:04 PM

Spruce is a bear to saw straight sometimes. More set, not less. I'm convinced it's not the hardness of the knots, but the grain around them that causes the waves. The dip or rise will usually start 6" before the knot and come down 6" after. If you look at the grain of the wood where the dip happens, it is almost perpendicular to the direction of cut, so the blade is actually cross cutting instead of ripping.

Now, none of that really matters when your customer just wants to saw it straight. I wish I had the answer. Thicker, wider blades help. The blade needs to be SHARP, that means you may have to change it out after every log. And more set, rather than less. But if you're in that .025"-.030" range you should be on the money. You could try .035" and see how it does.

ladylake · August 21, 2023, 04:07:47 AM

I'd set around 30 for spruce. Steve

kelLOGg · August 21, 2023, 04:21:23 AM

Gere, does your cat claw have a 4 degree setting? My early model didn't but I modified it by drilling holes to allow choices of multiple degree settings.

Gere Flewelling · August 21, 2023, 08:36:10 AM

Thanks for the suggestions. I think I will keep sharpening the 7 degree bands for this customer similar to the way I have but increase the set closer to the .030 range. He has a smaller hp engine on his manual mill. Is it still advisable to recommend he try some 4 degree bands on his mill? I can sharpen 4 degree bands with my sharpener. GF

Chuck White · August 21, 2023, 08:44:23 AM

I have sawn quite a bit of Spruce in the past, and have had best results with lots (.028-.030) of set and SLOW the feed speed!

The only bands I've ever used were Wood-Mizer Double Hard 10°!

Spruce knots are very hard and will cause waves!

Old Greenhorn · August 21, 2023, 10:29:43 AM

Those 4° blades are a big help on the lower hp mills. Especially on something challenging. They put less load on the engine and allow you to keep the blade speed up giving a better ut overall. They are just not as aggressive. IMHO he should give them a try.

ladylake · August 21, 2023, 03:56:37 PM

If I had to cut spruce with a 10°, deep gullet, light set blade I wouldn't cut it. Night and day difference with a 4° shallow gullet heavy set blade on the same log. Steve

Crossroads · August 22, 2023, 08:40:32 AM

Fully agree with the 4° blade in spruce. I've had some success using the 7° blades on big Sitka spruce, but more consistent results with the 4°. Part of my issue was that I was relatively new to running a mill when I was cutting more spruce and I was trying to push the mill a little to hard on the wide cuts while breaking down the log into cants.

jimbarry · August 22, 2023, 03:32:53 PM

I run 10º for softwoods. Mill has a 13hp gx390. For spruce, 3/4 push speed and 2800 rpm engine speed makes straight wood.

20210617 saw milling knotty spruce - YouTube

barbender · August 22, 2023, 10:19:37 PM

I should mention, there are two versions of spruce (irrespective of species). Ones that grew in dense stands, and ones that grew more out in the open. The ones that grow in the open (even in a less dense forest) are the ones that are a problem. When you get logs with knots that are much over 1" diameter, the juice really isn't worth the squeeze, IMO. Even if you can saw it relatively straight, lumber is pretty poor unless you need some wider form boards or maybe sheathing.

Crossroads · August 22, 2023, 11:59:39 PM

Ya gotta love a spruce tree that you have to limb it to fall it lol

Ianab · August 23, 2023, 01:33:56 AM

Quote from: Crossroads on August 22, 2023, 11:59:39 PM
Ya gotta love a spruce tree that you have to limb it to fall it lol

We have cypress trees like that. Drop it, and it's still 10ft in the air. Then it's a sketchy game of Jenga to get it on the ground. :-\ :D
But again these are overgrown farm shelter belt trees, crown as wide as they are tall sometimes.
I think the problem milling the Spruce is the difference between the regular wood and the knots. The clear wood is soft and easy to cut, while the knots are both cross / angled grain and much harder. Not impossible to saw, but you have to have the mill running sweet, and it will bring out any slight issues with band sharpness etc.

barbender · August 23, 2023, 09:11:50 AM

I've watched ugly spruce make a fool out of an out of tune swing mill before, too.

Gere Flewelling · August 23, 2023, 08:10:09 PM

I got working on the customers bands today using the variety of valuable info you have posted for me. The bands were all 7 degree though none of them were the WM Double Hard's. I was able to keep the gullets moderately shallow. I checked the existing set in each of them which averaged .021" prior to resetting. I bumped the set up to .031" on them and then resharpened. Checked the set on a couple after sharpening and de-burring. It was between .029-.030" on average. Hopefully these will be an improvement for this customer when he saws his spruce logs. Plan to recommend he try some 4 degree bands in the future. Is Kasco the only company that offers 4 degree bands? Thanks again for all your help with this issue. Can't imagine any place other than FF that would have provided me with such helpful info in such a timely fashion. GF

Old Greenhorn · August 23, 2023, 08:28:58 PM

Just wondering, why not take one of his 10° blades and resharpen it at 4° and let him try it? Yeah I know you have to go round a few times and it would shorten the band life (maybe). But when I sent re-sharps to WM after I realized 4° was the way to go for me, they sharpened them all at 4° for me, no problem. BTW, WM makes 4° bands, that's where I get mine.