Old School Sawmill Edger

[Brian Rupnow]

I'm still waiting for O-rings, but in the meantime, the brain never rests. I'm still thinking of a pattern embossed on the aluminum pulley in the area where it connects with the o-ring. The o-ring gets squeezed into a v-shaped slot with a flat bottom. If the sides of the v-shaped slots have an embossed pattern, I can imagine it tearing up the rubber O-rings fairly quickly. However, if the pattern was embossed only on the flat in the bottom of the groove, it would supply a lot of traction ensuring that the O-rings would be far less apt to slip, yet not tear up the O-rings. This makes the roller easier to fabricate. I can do a heavy knurl on the outside diameter of a 1" diameter piece of 01 steel, then part of a slice .075" wide and harden it. After heat treating it, put it in a handle as shown, mount the aluminum pulley on a mandrel and drive the pulley with my lathe. With the knurled piece held in my Q.C.toolpost lined up with the flat in the bottom of the pulley, then just crank the cross feed down tight and let the pulley make a few revolutions. I have never seen this done, but it seems like a good idea.

 

[Brian Rupnow]

A two hour heat soak in my wife's kitchen oven, and Hey-Presto--We have a new tool. The intent of this tool is to put a knurled pattern on the flat bottom of the v-groove in an o-ring pulley. Tomorrow I will do some functional testing and let you know the results.

 

[Brian Rupnow]

Really outstanding results with this new tool. Two pictures show tool in tool holder after being cranked in to bear on bottom of v-groove. and an identical groove made with the same grooving tool to the same depth but with no texturing in the bottom. I wrapped a 1/8" o-ring around the smooth pulley, and with a bit of tension on it, it slips in the groove. Did the same with the textured groove, and there was no slippage at all.

 

[Brian Rupnow]

This is the tool I ground to make all of the o-ring grooves identical. A simple plunge cut 0.070" deep and the groove is finished.

 

[CFLBob]

I'm impressed. Clever idea that worked as intended.

I was showing this to my wife and she said, "patent it." It seems like it's an obvious idea, but isn't that one of the tests for whether something is patentable? That is, if someone "skilled in the art" recognizes it as novel and useful.

 

[Brian Rupnow]

I don't see anything patentable. If my purchased knurling tool was narrow enough, I would have used it. This was just a work-around. Use my purchased knurling tool to make something really thin, harden the result, then use the result as a narrow knurling tool. Neat as Hell, but nothing really new there.--Brian

 

[Brian Rupnow]

Okay people--We have one side of the equation. This is a quote I received today for 100 foot of 1/8" diameter polyurethane cord and a splice kit.
From $83 to $94 for the 100 foot of cord, and over $500 for the splice kit.

 

[cwelkie]

Brian - have you checked the following vendor as a potential supplier? They are in the US but will ship USPS and I've had good service from them previously (no affiliation - just a customer). If not for this project they may be an option in the future ... theoringstore.com
Charlie

 

[Brian Rupnow]

SO--This morning my rubber O-rings showed up. There are 18.3 linear foot of o-ring, costing a total of $75.79 which works out to $4.14 per linear foot. The 1/8" round polyurethane that I had quoted was $83.00 for 100 foot. This works out to $.83 per linear foot. Conclusion is that o-ring material costs about 500% more than polyurethane material---if you don't consider the price of a splicing kit for the polyurethane.

 

[Brian Rupnow]

Here we are girls and boys. Ready to rock and roll!!! It is far too cold out in my main garage to set this up, so I have it set up on a piece of plywood screwed to my side reference desk. The aluminum box with the switch and handle on it is my coil box. I'm going to grab some lunch and then try to run this thing.---Brian

 

[Brian Rupnow]

I must have done something really, really bad in one of my previous lives. I'm all set up and ready to go, and I can't get the engine to run. It ran great the last time I used it, and nothing has been changed while it sat up on the shelf. Rest of my day will be tied up figuring out what the heck is going on with the engine.

 

[XD351]

I must have done something bad in about twenty previous lives as my woes are never ending ! My motto is make it three times as one of them has to be close to right !

You could try threatening it with a suitably sized hammer ! I”m sure that me standing there with menacing look on my face and a 14lb sledge hammer slung over my shoulder has intimidated at least three of my engine into cooperating!

Can’t wait to see it running !

 

[Brian Rupnow]

If at first you don't succeed, try a different engine. That doesn't always work though. I put the vertical hit and miss engine on as a driver this morning, and it starts and runs like a champion.--But---It doesn't have enough power to drive the edger. I tried many different tricks, but when the clutch lever is engaged, the vertical hit and miss engine just grunts and quits. This is rather bad news as all of my engines have a 1" bore. The stroke on the vertical hit and miss is slightly different (shorter) than the first engine I tried to drive this system with. I am now going to have a closer look at the throttle governed engine and see what is going on with it. I think it is more powerful, but only if I can get the darned thing to run. I have a couple of tricks left. I can monkey about with pulley ratios, and if that doesn't work I have my opposed twin horizontal engine which should be more powerful.

 

[Brian Rupnow]

I think I may have found out why my governor throttled engine wouldn't start. It may have been the result of a STUPID ATTACK!!! Having checked every possible thing I could, I decided that it must be a gummed up carburetor. So--I changed to a brand new carburetor.--And--While I was doing it I noticed that the top rocker arm on the engine operates the intake, not the exhaust. I have been bravely forging ahead with the engine valve timing set backwards. I don't have these stupid attacks often, but when I do, they're real doozies. I'm off to eat some lunch, then go for my fat mans walk, then come back and reset the timing. Gahhhhhh---

 

[Brian Rupnow]

We're fine!!! Engine now runs excellent with proper valve timing. How did it get out of time just setting on a shelf? That is one of those questions that I have no answer for. I don't have anyone in my shop but myself, and unlike some people I could name, I don't have any shop elves. I know so much about these small engines, that when an engine refuses to run and yet I think everything is set up correctly, it makes me crazy. Now I will bolt the engine back onto it's sub base and see if it will run the edger.

 

[Brian Rupnow]

The throttle governed engine does run the edger. There is an awful lot of stuff in motion and it's scary as Hell, but everything is working. I have to tame the engine down a little bit and get things moving at a more sedate pace, but I think this thing is actually going to work. I will post a video of everything working and a board going thru the edger --maybe tomorrow.

 

[Brian Rupnow]

Three things to do tomorrow. Engine has one "loose" flywheel.---Drill out #8-32 set screw holes and retap to #10-24. Link between governor and carburetor need one end to be adjustable.--Right now there is no adjustment on it and I need it to be adjustable to set the engine rpm range. Spring loaded pressure rollers on edger have to have adjustable stops added. Right now they ride right up tight to the textured rollers. The boards I am going to be edging are 1/8" thick material, so the adjustable stops will stop the pressure rollers 3/32" away from the textured rollers. This will make it easier to get the boards into place to start them feeding thru the saws, and will keep the textured rollers from marking up the face of the pressure rollers.

 

[PhilWroundrockTX]

SO--This morning my rubber O-rings showed up. There are 18.3 linear foot of o-ring, costing a total of $75.79 which works out to $4.14 per linear foot. The 1/8" round polyurethane that I had quoted was $83.00 for 100 foot. This works out to $1.20 per linear foot. Conclusion is that o-ring material costs about 340% more than polyurethane material---if you don't consider the price of a splicing kit for the polyurethane.

Just a comment: at $83.00 for 100 feet it works out to $0.83 a foot, not $1.20 a foot (@ $1.20 a foot it would be a cost of $120 per 100 ft). Makes the cost difference even greater. Just a comment - I tend to do this sort of thing fairly often.

 

[Brian Rupnow]

You're right. At $83 for 100 foot, that works out to 83 cents per foot. Not only am I old---I've forgotten how to do basic math!!!

 

[Brian Rupnow]