Author Topic: Projects.  (Read 4317 times)

4GSR

Re: Projects.
« Reply #135 on: April 14, 2019, 06:51:38 PM »
At least one of the wheels needs to be crowned.  1 to 2 degrees should do it.
Ken

Terrywerm

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Re: Projects.
« Reply #136 on: April 14, 2019, 06:54:30 PM »

Visit this site for a good explanation of crowned pulleys and why this works the way it does.  There is a video there too.


https://woodgears.ca/bandsaw/crowned_pulleys.html
Terry

Making chips with old machines!

f350ca

Re: Projects.
« Reply #137 on: April 14, 2019, 07:04:16 PM »
Read somewhere, might have been an old machinists handbook that only one of the pulleys should be crowned. Crowning them both it said would make the belt wander.

Greg

Carpenter84

Re: Projects.
« Reply #138 on: April 14, 2019, 07:27:23 PM »
I used to deal with a lot of conveyers when I worked in factory. I also deal with a lot of 4-6Ē paper on hundreds of rollers into my winding machine. The first line I ran in the first factory was an old machine, manual everything and flat rollers.
After a couple years they ordered/built a new line, I was able to help them design a few things. I had them crown a bunch of the rollers along the paper route, as the paper often changed direction, etc. It was especially necessary because a lot of the higher grade paper we had to use ran terribly. You could roll out 50í and it would twist up on its own. Pull it flat and it was so wavy you couldnít hold it flat, no way, no how.
I would crown the big aluminum drive roller, and maybe the bottom one. Iíll keep the top one flat for tension and tracking control... maybe I wonít crown the bottom one... since I turned the small rollers straight, it wonít be difficult to get those two to track properly. But the big drive roll, Iím not sure if itís out of align, or the belt is wavy, but it flaps on one side, canít straighten it out.
Either way, the big roll is aluminum, easy to crown. The other two are steel.
Shawn

First 9x42 column mill,
Enterprise 10x28 lathe,
Ko Lee 6x12 surface grinder,
Airco dip/stick 160 welder,
Fully stocked wood shop.

Carpenter84

Re: Projects.
« Reply #139 on: April 16, 2019, 09:31:18 PM »
I crowned the big drive wheel. I have no idea what the angle is, I donít have a compound on my lathe. I turned steps in about 1.5Ē from either side. About .007Ē deep each in 3/8Ē wide steps, then used an air belt sander/filer to smooth out the steps into an even taper. Then emery and scotchbrite smooth. The one wheel wasnít enough. I did the same to the top roller.

Thereís still some wandering, but it was due to tension. I tightened the belt up and it was much better. Each tracking adjustment had much less effect than before. Smoother. However, I have a fine balance between tension and bogging down this motor. I used the dc motor I removed from my lathe for the 3 phase.
The intension with all this was to build the proof of concept before spending any serious money on it. The 2x72Ē machines run about $2100 up here for a basic machine. All the add-ons push the price up past $3000.
So, when I built the platen and frame, I made it very beefy to make sure if this all worked well, it would be worth putting money into it. Rather than finding it all worked but it was too flimsy.

The other issue is Iíve got a bad bearing in that top roller, or, one of the bearings is crooked. Thereís a vibration in the top shaft that turns into a serious noise once you get up to 2000rpm.
Also, when I tapered that top roller, I exposed the seam between the pipe and end cap/plug the bearing is pressed into.

BUT, even with the noise/vibration and unhappy motor, I got it up fast enough to throw some serious sparks cleaning up the steel punch I had been using to push the shafts in and out of the bearings, grind the mushroom off the top, and slow it down to clean up my brass hammer head and wood handle. Lol. Definitely proved the concept though.

So, next steps.
Iím going to remake that top roller, get new bearings all around probably as they were all old bearings. Shitty problem is theyíre all in blind holes...
talk the boss into a 3 phase tefc motor and vfd.
Make the tool platens for both vertical and horizontal positions.
And expand the belt collection.


Shawn

First 9x42 column mill,
Enterprise 10x28 lathe,
Ko Lee 6x12 surface grinder,
Airco dip/stick 160 welder,
Fully stocked wood shop.