Floating arbor w/ collar circular headrig questions.

Robert.schade · August 16, 2023, 09:56:59 PM

Does anyone have any information on how floating arbors with a circle saw work? I'm a sawyer at a mill with a 56" circle saw and dealing with constant problems with the saw easily heating. Currently changing saws every 600-1000 logs and the saws are heating next to the collar and shaft. The ridge on the saw is always about 8 inches from the eye and can't figure out why. Can post pictures of the setup tommorow if anyone has ideas!

beenthere · August 16, 2023, 10:13:45 PM

Welcome to the Forestry Forum.

Do you have a copy of Lunstrum's Circular sawmills and their efficient operation guide?

https://www.fpl.fs.usda.gov/documnts/misc/circsaw.pdf

Sounds like the log is rubbing on the blade near the arbor. Lead needs to be correct, and the sawblade hammered correctly for a right or left handed mill.

Others here who know more, may chime in.

Robert.schade · August 16, 2023, 10:23:05 PM

Yes I have the book, personally have read the whole book. These floating arbors seem alot different than the original saws with the nut at the end of them. The shaft pops out 3/4 an inch at the end and held in place by 3 guides 2 in front 1 in the back. It seems the collars/ shaft warm up alot more often due to friction on the collar "floating" on the shaft. Currently they use chain lube to lubricate the shaft. No matter the change in lead we still run into problems. And the saws we get are hammered correctly from moraska saws. They run good for 400 logs and then the saw starts warming up. Sharpening the saw every 300 logs and using Chrome tips!

moodnacreek · August 17, 2023, 08:01:25 AM

This question is way beyond my pay scale. The only comment I can think of is to mention a point and click thermometer. Back when I was heating saws the problem was coming from the bearing. I slowed the saw down and went to thin grease and not much of it. Got by for years like that but when I pulled the mill out I found a spot where the off bearer belt rubbed the saw bearing so that was the real problem. Don't be afraid to try another anvil man either. And how does it run with wider bits?

DanielW · August 18, 2023, 08:04:05 AM

Do you have some pictures of that setup. I have a few circular mills at home, but also work for a company that makes larger, production-scale sawmill equipment. We use floating & splined arbors on our gangs etc., but I've seldom seen it on primary breakdown equipment/headsaws (admittedly most of our headrigs now are 12" bands, we don't do many circulars anymore). We tried guided circular headsaws once at a customer's request: This was on a scragg/sharp-chain system with dual 44" blades, and we had bad luck - just not enough guide to accurately keep things aligned for a primary breakdown/headsaw application. Ended up converting back to conventional arbors and shifting husks. For it to work well, you need lots of guide surface area and lubed guides.

Most of our guided saws on floating arbors have high-flow water/lube systems in the guides, which are constantly being re-faced and ground to very limited tolerances. The guides are large enough and tight enough to the saw that the low-pressure lube through the guide system acts on enough saw surface area to guide the saw within a couple of thou. Theoretically the saw never touches the guides - the lube keeps the saw spaced off - usually by about 0.002" or so.

I know a few other companies have tried guided and floating headsaws over the years, all with pretty minimal success. These were often converted back to conventional arbors. Is yours a splined arbor with shifting guides? i.e., does the saw shift on the arbor for curve-sawing or on a sharp-chain/C-Frame setup? I can't think why else it'd be a floating arbor. Pic's would be great.