Alternating Saw Mill

[Marc1]

Has anyone ever built a sawmill with a reciprocating blade ?

Providing it cuts to an acceptable speed, it should be much cheaper and easier to build than a band mill, have a thinner kerf than a chainsaw yet use a wide blade that will not wander in the cut.

 

[Sawmill_Bill]

reciprocating sawmill

I would think the limitation would be the stroke needed to allow the center teeth to clear sawdust from their gullets. If the sawdust is not ejected out the side, it will have to "spill over" in the kerf and that will cause all sorts of problems.

The next issue is how thick the saw plate would need to be so it would not buckle in the stroke. Is this to cut on the push stroke or the pull? The push stroke needs a thicker plate. A pit saw is a pull stroke type blade. The sawyer on top is the return.

 

[Marc1]

I suppose that's why the teeth of the saw are bent sideways so that the kerf is wider than the blade thickness. Also I think that the sawdust goes from one tooth to the next in each stroke until it is expelled by the last one.
Reciprocating saw do work.

If one would build two blades mounted on a crankshaft the whole thing can be balanced and vibrate much less. The distance between the blades could be adjustable...I don't know, I would like to know of any previous attempts.

I know about the chainsaw with reciprocating blade attached directly to the top of the piston.
Also have seen the frame sawmill from last century with a vertical recip. saw blade. None of this saw clear the sawdust with a long stroke. I suppose a vertical blade would allow gravity to help.

As for the cut, it would need to cut on the pull of course.
Having said that some jigsaw have blades with a double row of teeth that cut in both directions, but that would be very expensive to make.

A piece of a band saw from a large band mill say 4" wide would be ideal I guess.

 

[ASEMASTER]

just a thought

Just a thought to get you going on(your)project ,how about an old hand rip saw hooked to a 17" wheel used as a crank, hooked to a rear end with posi. use other axel and belt to drive the carrige,to a automatic with a hemmi to drive it, this should give you enought stroke and power to realy saw some wood .

 

[Ianab]

Hi Marc

Not built or seen one working, but they used to be common in years gone by.
I think they were a natural progression from the manual pit saw. Some very clever guy probably figured it would be much easier if he could power his pit saw from a steam engine instead of muscle power.
This is the sort of thing they would have used, it's in the Kauri museum in Northland, NZ.

This other picture is a later vintage gang sash mill, it has a series of blades at 1" and 2" spacing and was used to resaw larger cants into boards.

So I guess, yes your idea can work, it's been done before. I dont know how the speed and effiency where for those mills, the old sash saw was powered by a HUGE 4hp!! steam engine. But it probably cut 10 times faster than a manual pit saw and was an amazing saw at the time. I suggest you look into some old books and musuems for more ideas.

Cheers

Ian

 

[woodshop]

Ianab that Kauri museum looks like a pretty interesting place. Too bad it's on the other side of the world, about as far away from here as one can get I suppose.

 

[Ianab]

Yup.. it's a must see for any tree person

A couple more pics from there.

This is a 4" slice cut from the middle of a kauri tree, lengthways

And part of their chainsaw collection.

It's an hour or so drive north of Auckland city if anyone is ever in the neighbourhood, highly recommended.

Ian

 

[aggiewoodbutchr]

I've browsed the museum website before. I looks like it would almost be worth the trip just to see it. But... I guess while I'm there I could fit in some fishing, scuba diving and snow skiing.

 

[woodshop]

I've browsed the museum website before. I looks like it would almost be worth the trip just to see it. But... I guess while I'm there I could fit in some fishing, scuba diving and snow skiing.

I'd be down there figuring out a way to get some of the interesting wood that grows down there and nowhere else, back home here. How much does one of them huge containers cost? Probably for guys like me buying only one, if I could even do that... would be more than the lumber would be worth. Well... before I check out for good, I do want to get down to Australia/NZ part of the world.

 

[Ianab]

Good luck finding Kauri timber

In years gone by it was heavily harvested, and much of the original forest was cleared for farmland. There are still lots of Kauri trees, but they are mostly 2nd growth. As it takes 400-800 years for them to mature, they are only 50-100 year old babies. There are a few big ones and small areas of old growth in parks and reserves, but the species isn't harvested commercially any more

Ian

 

[woodshop]

Good luck finding Kauri timber

I understand Kauri is not available, but I know there are other woods down there that I can't get up here. I actually collect wood specimens in a standard 3x6x1/2 inch size. Have over 200 species so far from around the world. Most harvested myself, or gotten in trade with other wood collectors in parts of the world where common species here are rare there. So ianab... don't suppose you have a 6 inch piece of Kauri laying around your woodshop do ya????

 

[laternser]

Look for a sash saw

I came in late on this thread ... just joined arboristsite.

Google "Sash Sawmill"

There is such a sawmill in the U.S.

http://www.traditional-building.com/brochure/members/sashsawn.shtml