Building a model Drag Saw

[werowance]

nicely done Brian, curious, how does the engageing lever "feel" to the hand when engaging it? is it like a clunk or thud, or does it feel like grinding gears when trying to shift a car without the clutch pedal push? or does it just feel like a clutch? it seemed to engage very easily for you.

 

[Brian Rupnow]

So--Today the drag saw cut it's first log. Everything went very well, except that I need to get a more aggressive blade. About half way thru the log, the saw seemed to take forever until I gave it a bit of extra weight from my thumb. A picture taken after the cut shows that there were two knots hidden away in the center of the log. Everything works as I hoped it would. My dog clutch worked as I had hoped. (I never made one of them before). I will post another video after I get a more aggressive blade and put a spring on my dog clutch lever to keep it from rattling. I sell a complete set of drawings for this drag saw for $25 Canadian, but that does not include the engine.

 

[Brian Rupnow]

Werowance. I guess I could say it starts with a "clunk". There is nothing gradual about it. One second it is disengaged, the next second it is all in action. I wouldn't try to use a clutch like this on anything that was under a load and needed to be started gradually.---Brian

 

[werowance]

add a hack saw blade and you would have a power hacksaw very nicely done Brian.

 

[nel2lar]

Brian
Very nice build and it is all you wished. You mention how it was depositing saw dust to both sides of the log, that is normal because as the cutting stroke ends it has dust in each tooth that has not cleared the log carrying it in the back stroke and dropping it. A very nice video showing what a little bit of metal and the right person can do. Excellent job.
Nelson

 

[goody]

So dad’s Vaughn did use the dog clutch I think it had 4 dogs on it and I seem to remember a canvas or leather, possibly belting pad that worked like a synchronizer to bring it to speed but that was 60 years ago and I only saw it run once bucking up logs to be split. I didn’t get a chance to run it after my older brother rebuilt it in 1998. I could call the museum and see if they could send me a picture. In the YouTube video you can see the clutch being engaged, but no details.

Pat

 

[Ghosty]

Brian,
Another brilliant build, congrats on the saw. You may need to look in the hardware shops where the saw blades for the sawalls blades are kept, some of them have an aggressive tooth design.

Cheers
Andrew

 

[Brian Rupnow]

I just went downtown and spent $12 of the Rupnow fortune on a saw with a really radical tooth profile on one side. Tomorrow we will see about mounting it on the drag saw. I did find out something today. Saws that have a handle which spans both ends of the blade are only .024" thick. Saws that have a handle at only one end are .036" thick.

 

[Ghosty]

Brian, that look like a good saw, I seen this at the hardware shop this morning, its only 9" long, but you found one.

Cheers

 

[Brian Rupnow]

I installed the new saw blade, drilled a few cosmetic holes in the dog clutch handle, and put a very weak tension spring on the dog clutch handle to keep it disengaged. When it is engaged and the saw is moving, it seems to stay engaged without much of a problem, although I can disengage it quite easily by moving the lever. Even with the new aggressive sawblade, this thing is no speed demon at getting thru a log. When you've been used to chainsaws all your life, this thing cuts pretty damned slow by comparison, but 100 years ago it certainly would have seemed like a marvel to two men on a manual crosscut saw. The batteries for my camera are charging right now, so I might get the final video up before the day is over.

 

[Johno1958]

Good job on the saw Brian. I agree how much of a marvel it must of been to the guy's on the cross cut saw back in the old days.
If I went back in time and landed on one of those two man cross saws I would give my self about 5 minutes before I was
huffin and puffin and whining about my back.
Cheers
John

 

[whitehouse260]

I wonder if adding a small amount of weight to the tip of the saw blade would help it cut faster?

 

[Brian Rupnow]

Whitehouse250--yes, it would help a lot, however I am trying to maintain a profile similar to that of the old antique dragsaws from 100 years ago. I have two choices, it seems--add a weight to the arms, or find a log that saws easier. I just spent an hour and a half on the telephone trying to chase down a supplier of 3" diameter balsa wood, but had no luck. I did find a supplier of basswood, but they didn't know if it would saw easier than the spruce log I currently have or not.

 

[BobsModels]

Brian

I have never seen a drag saw with a weight. I have seen the Economy, Ottawa, and Witte. When a teenager my grandfather cut wood for his furnace. He would go out on my uncles farm and cut up fallen trees. I helped and he had no power saws. The larger diameter were cut with a two man saw. He taught me that the saw did the cutting all we did was push - pull it. If you tried to force down you buckled the blade. It was just a nice see-saw motion and the teeth cut at a speed that was smooth. Sometimes you actually had to hold the blade up a bit to get the cut to go. The oaks, hickory, and cherry were the worst. The walnuts were like butter (probably why carvers and turners like it). Butternut trees not too bad. If you wanted to re-sharpen your blade try cutting an Osage Orange tree. When I would use a cross buck saw it was the same thing no pressure. So when I took up wood working and using a handsaw it was easy for me just let the saw work.

At the fair I mentioned the wood was real wet and he had to hold the blade up to try and get the cut going.

Bob

 

[Brian Rupnow]

This will be my final video of the drag saw, and I am deeming it a success. It cuts logs the way it is supposed to, and the engine has ample power.

 

[Brian Rupnow]

So--an interesting comparison. In the first video, using a newly sharpened carpenters saw, the saw took 7.2 minutes to cut thru the log. In the last video, with a much coarser style of saw profile, the saw took 3.2 minutes to cut thru the log. That is more than twice as fast.

 

[velocette]

So--an interesting comparison. In the first video, using a newly sharpened carpenters saw, the saw took 7.2 minutes to cut thru the log. In the last video, with a much coarser style of saw profile, the saw took 3.2 minutes to cut thru the log. That is more than twice as fast.

Hi Brian another interesting project completed.
A dedicated cross cut saw doing a much better job of cutting and clearing wood fibres.
Eric

 

[goody]

Nicely done Brian, the larger blade is more in line to scale with a full scale saw. As I said the teeth on the Vaughn were 2” with a double cut profile so it cut on both strokes the end of a single tooth had a W profile with both sides sharpened in between the wider W teeth was a V tooth I don’t remember the set on theV tooth but I think it was a raker it was slightly shorter.
WVWVWVW
Pat

 

[Ghosty]

Brian,
Another top build, will be looking for your next build.
Cheers
Andrew

 

[nel2lar]

Brian
The only reason the saw dust falls on the back of cut is because the final teeth bearied in the log has the sawdust captive in the tooth and the log will not drop until it is out of the log on the return stroke.
Beautiful, very nice job.
Nelson