Model Sawmill Dreaming---

[johnmcc69]

Brian, you are a madman.
I can't believee how quick you take your ideas
from "paper" to finished part.
I don't know how you do it.

John

 

[Brian Rupnow]

johnmcc69--You're right. I am a madman. And I've been this way most of my life.

 

[aonemarine]

OK re read, Got mixed up looking at the line for the no power feed on the mill, guess thats what i get for just scanning the pictures LOL.
Hopefully you under stood me with what I was talking about on the power feed not being able to move forward until the load is off the blade, probably by holding up the paw somehow until the load is off the blade. I probably should just keep my mouth shut and go back to lurking.....

 

[Jasonb]

What about if just the blade were tilted or actually tapered, think of it like a keyway broach.

Talking full size if the blade were 3/8 narrower at the bottom then by the time it reached the bottom of the stroke it would have cut 3/8" into the wood. As soon as the blade starts to rise the cutting edge will move away from the sawn timber allowing the log to be advanced by not more than 3/8" ready for the next stroke, just like putting a shim into the broaching bush.

The easiest way to do this on the model would be to just offset the top and bottom mountings by your "taper length" either the actual blocks or the holes in the blade

 

[bret4]

I think your on to something jasonb. I just found this video that shows the blade motion like you mentioned.

http://www.steinkjer-kommune.net/eggevandring/egge/index.php?meny=23

 

[Cogsy]

I just found this video that shows the blade motion like you mentioned.

http://www.steinkjer-kommune.net/eggevandring/egge/index.php?meny=23

What an awesome piece of machinery. The reversing procedure, even pulling up the next log, simple, economical and ingenious design.

 

[Brian Rupnow]

Thanks--Great video. I see what you mean about shaping the saw like a broach.---brian

 

[Brian Rupnow]

So there we have it. The inner and outer frames are completed except for some cosmetic work. The inner saw frame slides up and down quite nicely between the two outer columns. (Thats not a saw blade in there---its my 6" machinists ruler----It just fits!!!)

 

[Bastelmike]

Hello Brian,

excellent CAD-work ! And perfect 2D-drawings, You are really a professional !

One concern I have is using a standard gear profile for the ratchet. All ratchet drives have a special non-symmetric profile for the teeth to prevent the ratchet from slipping out to early (during the forward movement), hope the picture will clarify this.
But the rounded profile of the gears will make this possible, depending on the angles of force during the stroke.

Mike

 

[bret4]

What an awesome piece of machinery. The reversing procedure, even pulling up the next log, simple, economical and ingenious design.

That second water wheel for reverse is a great idea. Someone put a lot of thought into getting the most out of water power on that one.

 

[Brian Rupnow]

Bastelmike---It all depends on the angle of the dangle!!

 

[Brian Rupnow]

 

[Brian Rupnow]

 

[Brian Rupnow]

Here is the "eccentric shaft" made from 4 built up peices. Everything is positioned correctly, with a 3/8" square spacer between the "webs" and all joints drilled and reamed for .093" cold rolled "pins", cut from.093 cold rolled rod. After silver soldering, I will cut the longest shaft out between the webs, thus giving a "true" shaft with the correct offset to the "throw" journal. This is the way I build most crankshafts for model engines.

 

[Brian Rupnow]

And here we have the finished eccentric shaft---All silver soldered, cut out, and ready to rock and roll!!! The con rod journal hasn't been polished, but since none of the siilver solder migrated onto it, thats okay. I will polish it later.

 

[aonemarine]

How far will the log advance per crankshaft revolution??

 

[Brian Rupnow]

I don't know. That is why I have an adjustable eccentric . By dialing in the adjustable eccentric , I can set how much the log advances with each downstroke of the saw. The carriage sets still and doesn't advance at all when the saw is on the upstroke.It only advances on the downstroke of the sawblade and I am the guy that determines how much. Obviously, too much and it will stall the engine I have driving it. I would LIKE to think I could advance it about .030" each stroke, but I really don't know.

 

[aonemarine]

.030 sounds like alot per stroke IMHO. If it doesnt cut the full depth for the amount of advance it could get ugly. Maybe try the blade out in a coping saw to get a feel for the blade pressure and the depth of cut?

 

[Brian Rupnow]

Well, now I know why I've been feeling so CRANKY all day.-----Groan----

 

[aonemarine]

Looks great!!! Would also make for a good interrogation device. I'll leave it up to everyone's imagination as to what parts of the body could be feed into it for best results lol