Old School Sawmill Edger

[Brian Rupnow]

I'm all "engined out". I've been thinking about something to build and run with one of my engines. I already have a sawmill, a buzz saw, a steam donkey winch, a drag saw and a wood splitter. I have been thinking of an edger. Once a log has went thru the main-saw in a sawmill, the resulting boards have bark on the outer edges. This requires a second cut to be made to remove the strip on each side of the board which are known as "edgings". Old school edgers had two sawblades on a common shaft. One sawblade was "fixed" in position, while the other sawblade could be moved on the shaft to accommodate different board widths. They also had powered pressure rolls on the outfeed and infeed to draw the uncut board into the saws and to feed it out the other side when the cut was finished. A later development were "Bull-Edgers" which had multiple blades with spacers between them, so a wide board could be fed in and finish size narrower boards and two "edgings" would come out. The edgings on each side fell down onto a conveyor that took them to the chipper, while the boards passed on thru to the sorting shed to be sorted, graded, and stacked to dry. I think that one of the old style edgers might be fun to build. The blade on my buzz saw is about 3 3/8" diameter and I can cut "logs" of 1" diameter into stovewood lengths. (about 1 1/2" long). I want to do a bit of research and see if there are blades about 2" in diameter.--I could probably use slitting saws intended for metal work.
http://bbs.homeshopmachinist.net/threads/56666-Model-Sawmill-Dreaming?highlight=sawmill
http://bbs.homeshopmachinist.net/threads/65982-Buzz-Saw?highlight=sawmill
http://bbs.homeshopmachinist.net/threads/65855-Model-Woodsplitter?highlight=sawmill
http://bbs.homeshopmachinist.net/th...am-Donkey-Engine?highlight=donkey+steam+winch
http://bbs.homeshopmachinist.net/threads/77077-Building-a-model-Drag-Saw?highlight=drag

 

[Brian Rupnow]

I did find some 2" diameter sawblades. The sawed lumber from my sawmill is only about 1/8" thick, so these blades should be about right. The actual thickness that a circular blade will cut is half of the saw diameter minus half of the hub diameter.
https://www.amazon.ca/Proxxon-28020-2-Inch-HSS-Blade/dp/B000S6DTT0

 

[Brian Rupnow]

I find sawmill machinery fascinating. There were four sawmills in the village where I grew up, near Bancroft. Of course I only seen them from a kid's perspective. By the time I was old enough to understand what all the different machines actually did in a mill, all the sawmills were gone. I did spend a couple of years as an adult designing high production sawmill equipment and installing it. The thing I like most about the old sawmill tech, is that it was so "In your face". Very little was covered with guards and you could see all that beautiful machinery doing it's thing. Very unsafe and dangerous for the people who worked in them (My dad lost a couple of fingers running the "resaw" in the Bancroft planing mill), but very pleasing to the eye when done up as a model. Even the models are dangerous--You have to exercise good "finger awareness" when running them.---Brian

 

[Brian Rupnow]

Okay--Lets think about what I need. Engine with a governor--Yep, I have half a dozen of those. 2" diameter sawblades--Yep, I can order them from Proxon or Harbor Freight. Shafting will be cold rolled steel in "stock" sizes . One sawblade is fixed--no problem. One sawblade has to be able to slide along the shaft but still be powered by the shaft, to adjust for different board widths. Maybe a double keyway, one on both sides of the shaft and long keys, with two keyways in the moveable sawblade hub.Two powered rolls, and two pressure rolls for infeed and outfeed. Not sure at the moment, but maybe diamond knurl 4 pieces of cold rolled steel to act as textured finish on rolls. Some profiled pieces of flatbar to act as anti-kickbacks on the infeed side of the edger. A frame to hold all the bearings and shafts, etc, in place. An infeed and an outfeed table---This is where I broke one of my own rules---NEVER THROW ANYTHING AWAY!!! When I was building my sawmill, some kind fellow in USA sent me a whole bag of 3/4" square oak. I used it to build my sawmill carriage, and hung the bag with the rest of the oak on a nail in my storage closet. Couple of years ago in a cleaning frenzy, I thought, "Aw heck, I'm never going to use that stuff", so I pitched it out. Dumb Bastard!!! The sawblades are going to have to run at engine speed 1200 rpm or a bit faster. The infeed and outfeed rollers are going to have to run at considerably lower speeds, so some gearing is going to be called for. What have I missed?---Brian

 

[Brian Rupnow]

Amazon was happy to take my money for two of the Proxxon blades.

 

[Brian Rupnow]

A bit of preliminary layout work shows the two 2" diameter Proxxon blades. Since the center hole on these blades comes in at 13/32" diameter, that pretty well dictates the size of hub I can have. And of course, the hub outer diameter pretty much dictates what the hub inner diameter can be. This in turn, dictates the size the shaft will be. Turns out I can use a 1/4" diameter shaft, which should work fine. The fixed blade is going to be locked in one position on the shaft. The moveable blade (which is moved to accommodate different board widths) must be driven in sync with the fixed blade, so to do that we have a couple of long keyways in the shaft, and a couple of keyways in the hub of the moveable blade assembly. As in all designs, the project must start with the items which are purchased and then the size of everything around the purchased components is "custom sized" to accommodate the purchased part, which in this case is the sawblades.

 

[Brian Rupnow]

Since the movable saw must move on the shaft to accommodate different widths of lumber, that means that the hub must have an extended head on it to accommodate a "shift fork".

 

[Brian Rupnow]

And, since this is supposed to be "Old school", we'll support that saw-shaft with a big old set of pillow block bearings. now that we have the bearings in place, that will indicate what the frame width need to be.

 

[Brian Rupnow]

The edger has two driven rollers as shown, along with two pressure rollers from the top (not shown). The position of the top side of these driven rollers is determined by the fact that the underside of the board passing thru the edger does not interfere with the hubs on the saw blades. Positioning in the other plane is established by the fact that you don't want them so close to the sawblade that they touch it, and you don't want them so far away from the blade that the board will "bend" when it encounters the blade.

 

[Brian Rupnow]

Locating all of the rollers and bearings lets me then design a frame to support everything. Still have to design infeed and outfeed tables and a "fence" to guide the board straight into the rollers. This all goes very rapidly, but will slow down a bit when I start adding the belts and sprockets which power the saw and the bottom rollers.

 

[Brian Rupnow]

Add in an infeed table and an outfeed table, along with a material guide/fence, and that's almost got it. Only things missing are the anti-kickback fingers on the infeed side and the drives.

 

[werowance]

so how will the boards be pulled through? or since its a model will it just be pushed through by hand?

 

[Brian Rupnow]

The infeed and outfeed both have powered rollers on the underside of the board, and spring loaded pinch rollers directly above them. They grip the board, feed it through the sawblades, grab it again on the outfeed side and power it all the way thru onto the outfeed table.

 

[Brian Rupnow]

Looking up from underneath you can see the long handle sticking out at the infeed end. This handle position is adjusted by the "edger man" to change the distance between the saw blades to cut different widths of board.

 

[johnmcc69]

Cool stuff Brian!

Keep it coming.

John

 

[werowance]

I can already hear the high pitch whine of spinning steel cutting lumber

 

[davidyat]

Brian,
This thread reminded me of the Hull-Oaks steam powered sawmill, I believe, in Oregon. Their band saw can saw a log so long that the guy adjusting the thickness of what is being sawed, is actually riding on the carriage. They create so much saw dust, that it's used to feed the boiler that creates the steam. Fascinating place.
Grasshopper

 

[Brian Rupnow]

Today I am working on the drive for the saw blades and for the infeed and outfeed rollers. The rollers will operate at a much lower speed than the sawblade. This calls for a bit of trickery. In this picture you see a gear reducer I built about 10 years ago, with a sprocket on the output shaft. As positioned it would provide a great drive for the rollers, but any drive to the sawblades is totally blocked. I've had that small 8:1 gearbox setting around here for ten years, but today is the first time that I've actually went ahead and modelled it.

 

[Bighoss]

I'm all "engined out". I've been thinking about something to build and run with one of my engines. I already have a sawmill, a buzz saw, a steam donkey winch, a drag saw and a wood splitter. I have been thinking of an edger. Once a log has went thru the main-saw in a sawmill, the resulting boards have bark on the outer edges. This requires a second cut to be made to remove the strip on each side of the board which are known as "edgings". Old school edgers had two sawblades on a common shaft. One sawblade was "fixed" in position, while the other sawblade could be moved on the shaft to accommodate different board widths. They also had powered pressure rolls on the outfeed and infeed to draw the uncut board into the saws and to feed it out the other side when the cut was finished. A later development were "Bull-Edgers" which had multiple blades with spacers between them, so a wide board could be fed in and finish size narrower boards and two "edgings" would come out. The edgings on each side fell down onto a conveyor that took them to the chipper, while the boards passed on thru to the sorting shed to be sorted, graded, and stacked to dry. I think that one of the old style edgers might be fun to build. The blade on my buzz saw is about 3 3/8" diameter and I can cut "logs" of 1" diameter into stovewood lengths. (about 1 1/2" long). I want to do a bit of research and see if there are blades about 2" in diameter.--I could probably use slitting saws intended for metal work.
http://bbs.homeshopmachinist.net/threads/56666-Model-Sawmill-Dreaming?highlight=sawmill
http://bbs.homeshopmachinist.net/threads/65982-Buzz-Saw?highlight=sawmill
http://bbs.homeshopmachinist.net/threads/65855-Model-Woodsplitter?highlight=sawmill
http://bbs.homeshopmachinist.net/th...am-Donkey-Engine?highlight=donkey+steam+winch
http://bbs.homeshopmachinist.net/threads/77077-Building-a-model-Drag-Saw?highlight=drag

I actually have a full size edger like the one you are building. It has not been used in years along with the circular mill with over a 50" blade.

 

[Brian Rupnow]

Well, --this looks good.--But there's a problem. Since the bottom infeed and outfeed must revolve counter to the rotation of the saw, I'm going to have to add a "reverser" in there somewhere.