sawmill blade.

Presently reassembling a sawmill I picked up. A few years back in this forum some guys were talking about the blade being "hammered" to run at a particular speed. How do I determine the correct RPM for a 48" blade? Also,while studying ancient sawmill operating techniques, the author said to set the "lead" at 1/32" in a procedure called "lining the saw" Can somebody explain these terms? Thanks, Fritz

This guy has as much information about saws as I have ever seen.

http://senecasaw.com/

We always used a 1/16th inch lead. The word 'lead' is used as in 'lead a dog'. If the saw cut exactly parallel to the log, it would always be rubbing the log. To avoid this the leading edge of the saw teeth must be set so it cuts 1/16th inch closer to the log than the back edge of the saw, as viewed from above. That way friction is reduced, the saw will not heat up & the saw will not bend & cut thick & thin lumber. The lead is sometimes built into the sawbox track holders, the front track holder being 1/16th inch closer to the sawbox than the back track holder. Then the saw guides can set set to help maintain the lead in Hickory & other stubborn woods.

Around here they call it putting a "set" in the saw blade.

Untill showcrop answered I had no idea what you were talking about. It has always been set and the tools to do that with are a saw "SET" no mater if a large or small circulat blade or a handsaw. You go to look to buy that tool and look for saw set.

I will get back to you later with a book you can download that explains it all. Also gives very good instructions.
Best book on the subject I have ever seen.
Got to run right now but will get back to you later today.
Richard in NW SC

Sawmill teeth are swaged, not set. The blade it set.

I don't know that there is any particular speed for a 48" blade. I believe the blade is hammered for whatever speed the mill spindle runs.

We bought a used blade for our mill long ago. No idea what speed it was set up for. We found the speed where the blade stopped wobbling and stood up and set the governor there. You will know when you are at the right speed.

A couple of the other guys explained the lead already. We used about 1/16".

(quoted from post at 08:31:13 03/27/19)
Around here they call it putting a "set" in the saw blade.

Click to expand...

"Set" refers to the width the teeth of a saw are "set" to using a saw set. "Hammering" refers to the tension within a blade so that when it's running at speed it's flat and not wobbling or dished to one side or the other. "Lead" refers, as was explained, to the geometry of the saw blades cutting edge vs it's tailing edge.

The "Disston Saw Book" had a lot of this information, but it's dated information.

I'm setting up a saw mill also. Had a 48 blade that was stolen. I could only find a 50" to replace it. 1/32" is what's called for a 48" blade. 1/16" for larger blades 52". As you saw the log you don't want the blade side rubbing the log. This causes heat.

As for speed normally the blade is set to the speed of the mandrel but you may be able to get but tweaking the engine speed to the blade.

Where are you located.

I don't know where your located, but there is a blacksmith shop in Rice MN that specializes in saw repair.

Usually blades are hammered to run 500 rpms but they can be hammered for lower speeds when you check your lead make sure the saw isn?t touching the guides or it will throw your measurements off does the saw have inserted teeth or is it a solid tooth saw

Here is the link to the US military manual for sawmill setup and use.My Dad, a retired WWII Colonel, got one of these for me.
I have it around here somewhere.
I have had a Turner sawmill since 1977 and sawed our house out with timber from our place.
Good info in this manual when you get to the section on setting up a mill and blade.
Sawmill teeth are swaged, not set. I have a swage that widens the teeth when the get worn. Makes them last much longer.
This manual even tells how to hammer a blade. I always took mine to a professional to have it hammered.
Richard in NW SC
Untitled URL Link

Brother has a small circle sawmill that was giving him trouble with the blade heating sawing hardwood lumber,he carried it too a shop that makes and repairs blades to get it hammered, the repairman told him if he would let him install carbide strips in the side of the blade it would solve his problem,he had them to make a new blade with the inserts and hammer his old one,he installed the new one on the mill and just as then man said problem solved he said to prove the inserts worked he stopped in the cut several times with no problem with heating,he said before hand if you slowed the travel speed down to much the blade would look like it was going to lay over, he said the inserts trim the wood fibers keeping them from making little if any contact to the blade sides which is what causing heating, it's still on the mill.

I have seen these people running a supply truck here in Tennessee.
http://www.piperssaw.com

Before my dad passed in 1985 he had a 48 inch belsaw with carbide teeth. It was originally powered by a JI case and a flat belt. Under load, the tractor would slow down and cause the 48 inch blade to warp and not cut true. So he use two 3 phase motors to keep RPM's constant. Not sure what HP motors he used or the RPMs. I think my dad experimented to find the RPMs that worked best.

Lead is adjusting the saw so that the leading edge (cutting side) is closer to the carriage head block then the back side of the saw.
Lead is set by adjusting the bearing nearest to the drive pulley to move the mandrel shaft back or forth on the one end.
This causes the mandrel shaft to be slightly out of square with the carriage thus angling the blade so that it closer to the carriage on the cutting side.
Some mandrel shafts have 3 bearings, in that case the middle bearing adjusters are backed off until the lead is set with the bearing nearest the pulley.
Then the middle adjusters or turned in to hold the bearing but must not be adjusted in too much on ether side to cause the shaft to deflect or bow in the middle.
Doing so will mess up the lead and cause stress on the shaft, possibly causing it to break at a later time



When setting the lead one needs to make a mark on the saw blade and measure the distance to the 1st head block on the carriage, then rotate the blade to move the mark to the back of the saw and move the carriage down so that you measure the same spot on the front head block again.
This insures you don't get a bad measurement due to a warped blade or slightly out of line carriage.

We've never ran a 48" but it should run similar to the 52" saws used at the local mill I worked at.
I'm assuming the saw has inserted teeth, if so I recommend a set of carbide teeth, they last much longer and require very little maintenance. Standard inserted teeth require swaging and ether filing or grinding.
Swaging is a learned art, one that I haven't practiced in nearly 20 years since they switched to carbide teeth.

Many years ago saws pulled by steam or low hp engines operated at 400-500 rpm's but that also required the log to be feed thru the saw at a slow speed.
Later with more powerful engines and early electric mills saw speeds increased to the 550-650 rpm range allowing the log to be sawed faster, thus increasing production.

The mill I worked at runs 52" main saws with 150 hp electric motors operating at 725 rpm, for large dia logs they also have a 36" top saw located above and slightly forward of the main saw, this saw is powered by a 50 hp electric motor and runs at 600 rpm. On a small 12" tie log they can cut 4 slabs and product 1 board and a finished 7x9 cross tie in 35-40 seconds.

With a gas or diesel power unit one can adjust the rpm's up or down the find the speed the saw operates at best.
but once the shaft speed is set any good saw shop can hammer a saw blade to operate at that speed.

(quoted from post at 14:54:04 03/27/19)

Sawmill teeth are swaged, not set. I have a swage that widens the teeth when the get worn. Makes them last much longer.

Click to expand...

I know what you mean, but they were asking about setting a saw and that's different than swaging. Of course swagging does serve the same purpose as setting in a crosscut, but it's just going to confuse people when you get into that. Some real old saws didn't even have swaged teeth, but I don't imagine anyone is using them anymore. In fact, I'd bet most people are running insert tooth saws these days if they run a circle mill at all. Bandsaws seem to be the thing today.

https://www.fpl.fs.fed.us/documnts/misc/circsaw.pdf

Add a half a ream of paper to your printer & print this out. It's some good reading on circular sawmill operation.