Circular Saw Mill questions and thoughts

[brer]

I just lucked into a 42 inch circular saw blade, built for the US army in the late forties, still in the original packaging and cosmoline.

I am a total newb to saw mills, but I believe I can make a functional saw mill out of this blade. I am kind of leaning to using my tractor's PTO as the power unit, and a bit of machining from the local Vo-tech to make anything I can't order.

My idea is to make a fixed position saw mill vice the portable ones that are pretty common on this forum.

Aside from the issues involved with the mill being in stationary, what are the major issues involved with using a large circular blade.

 

[les-or-more]

What do you have for a tractor? if the tractor is 540 rpm only you may have trouble running the circle up to the speed it is hammered for.

 

[rarefish383]

I have no knowledge of the old mills themselves. A friends cousin restored an old fixed blade mill and he mills old telephone poles. He'll spend a day pulling old nails and staples out of them. He uses the planks to build out buildings on his farm. The creosote has turned the wood dark pink and makes an interesting building. He uses a 6 cylinder diesel to run it. Good luck on your project and keep posting. I'm new here also and would like to see and learn what all is out there, Joe.

 

[Philbert]

what are the major issues involved with using a large circular blade.

There are potentially many safety issues involved with a large blade. Start by looking at commercially available saws of this type to see what types of guarding and safety devices they have incorporated.

If you look through their literature it may direct you to standards, guidelines, and some good ideas to copy.

Just a thought.

Philbert

 

[Brmorgan]

What do you have for a tractor? if the tractor is 540 rpm only you may have trouble running the circle up to the speed it is hammered for.

That's what pulley ratios are for, assuming the engine's got the torque to drive it. And a 42" blade doesn't need to turn very fast - even at 540 RPM, its cutters would be hitting the wood at just a shade under 6000 FPM, which is faster than most bandmills. I don't know what the ideal is for a 42" blade, but I know the big bucksaw that I used to run at the sawmill didn't spin very fast, and it must have been at least 42".

The main issue I can think of with large circulars is the extreme danger and potential for severe injury or death. I know an old guy whose brother back in the '40s got a pantleg caught in the drive belt of one of these old circular mills that the family ran, and it threw him straight into the sawblade. He said it cut him open just like a sardine can and he bled out in a couple minutes. New circular mills are built with guards to prevent this kind of thing, but old and DIY ones might not be.

On the other hand, circular mills with sufficient power are generally the fastest, though not necessarily the smoothest cutting. They're also a bit more size-restricted compared to bandmills, since the maximum log diameter is pretty much limited to half the saw's diameter at most. You'll also need to design some sort of carriage assembly that can both hold the log securely and allow for easy rotation and adjustment. Good find though. I know the US Army operated myriad small bush mills like that up here in Canada back in the Forties while the Alaska Highway was under construction, milling such things as bridge timbers and pilings. I have a book on it with a few pictures of such mills, I think.

 

[brer]

I'm pretty sure the 540 setting on my tractor's pto will handle the rpm. Based on the research I've already done, the speed is not going to be a factor. Power, I'm not sure about, but I have access to bigger tractors.

I have been planning on using direct drive with a drive shaft that has a clutch. I'm probably going to be putting a flywheel on the bearing shaft to save wear and tear on my gear box.

Safety devices! That is the biggest type of input I am looking for. Things that may seem obvious to many of you, aren't going to be that obvious to me. I am figuring covered drive shafts and some type of feeding mechanism for starters. other than that I haven't been able to come up with anything other than using a metal detector on all inbound logs and staying the heck away from the feed side when cutting is occurring.

I take the advice and keep doing research.

 

[Backwoods]

Why reinvent the wheel?
There are plenty of them old sawmills sitting around not being used that you could restore much easier and probably cheaper then building one from scratch.

 

[M.R.]

Why reinvent the wheel?
There are plenty of them old sawmills sitting around not being used that you could restore much easier and probably cheaper then building one from scratch.

:agree2:

Years ago I picked up a never used Belsaw model A sawmill.
It came with track to cut 6' lumber, a hand crank feed, & a 42" insert tooth blade. By the time I priced the power feed, extra track, etc... I Lost a lot of interest in setting it up to use.

Might Google for a little research some phrases like.... Belsaw sawmill, Foley Belsaw sawmills

 

[billstuewe]

I concure with Backwoods--Why not just find a mill that you can buy that would use your blade. There are 100's of mills listed at this site, most are band but lots of circle too--I counted over 50 circles:

http://www.sawmill-exchange.com/circula2.htm

 

[Brmorgan]

Well, that might be the logical and most cost effective approach, but if he's anything like me, there's just this overwhelming appeal about building something yourself and watching it work.

 

[BobL]

Well, that might be the logical and most cost effective approach, but if he's anything like me, there's just this overwhelming appeal about building something yourself and watching it work.

I agree - it depends what your specific end game is. Most folks want to get from A to B because they are interested in what's at B, but some people are in it for the road trip, while others are in it for the nitty gritty of the machinery. I guess it takes all sorts.

 

[brer]

I will admit a certain love of tinkering. Plus the warm feel when you make something really complicated work like a charm.

Plus, based on the cost of most of those saws, I think I can do it a bit cheaper.