[Sanghera]

Hi everyone,
I have decided to build a second cnc router. The first one was made of wood and this one will be made out of metal. Using mostly simple shop tools. I am 17 years old and can use some of my highschool's metal working machines. I am posting this to give back a little to the site. I have learned from other people's machines and now can show other people my own as I build it. It should be done in about two to three weeks. Here are a few pictures, it looks rough right now but I have just finished painting. For the x - axis I used bearings inside of channels. This was my idea. Three bearings, the middle one is adjustable with eccentric bolts I made on the lathe. I can show a simpler method of making good eccentric bolts for bearing adjustment aswell. The Y - axis runs on v-wheels that I made on top of angle. Two on top, and the one underneath adjusts tension. Right now, both run very smoothly with basically no play. The Z-axis is still up in the air right now. I'm not sure how I am going to do it. As for controls, I already have everything I need from the last cnc router. Let me know what you think and if you have any suggestions or questions I can answer.
Sanghera.

[joecnc2006]

in the third picture, I can see the middle bearing riding and providing tension to push downward and hold the two outer bearings in the c channel, would it be better to have two one on each end, because you may get a little rocking forward and backwards.

Joe

[Sanghera]

So you mean, tension the two on each end up, against the middle bearing? Instead of the middle bearing pushing the two down? I never thought of that. But, it doesn't seem to be rocking for me right now, and to change it would mean to change that whole bracket. It would take a lot of force to rock that thing forwards and backwards. When I put the machine back together I will check this.
Thanks.

[Sanghera]

Here are some more pics after painted. I'm not sure yet if I should put a clear coat on.
Is it necessary?

[Sanghera]

This is the base.

[swarfmacdaddy]

Please, more on the eccentrics.How did you make them?

[joecnc2006]

an eccentric bolt can be as simple as example in this case instead of having a circle hole where the bolt fits into you have an oblong vertical hole like this ( 0 ) not this ( o ) and when you place leverage to the bearing to ride against the top rail you lock down the bolt and washers in this possition to the actual bolt is in the upper portion of the hole. I think (maybe not sure) in the picture above he used an offset hole in a cap of some sort.

Joe

[Sanghera]

In post number 4, in the second picture mostly, you can see the offset in the bushing in the middle bearing. Instead of having the bearing mount in the center of this bushing, it is 1/8" offset from the center. This gives me 1/4" adjustment theoretically. I do not need this much adjustment, the reason it is so much is that it allows me to put the slide into the channel easier.
Sanghera.

[Thazul]

Love the pics, keep them coming, and keep up the good work!

[Sanghera]

Thanks. I finished putting on the clear coat. I will probably put the x and y axis together tomorrow. It's amazing how much difference paint can make. It looks a lot better with the paint. I will post more pictures of the progress tomorrow.
Sanghera.

[Sanghera]

Most of the plans are coming from my head as I go along. Or from scrap pieces of paper. I might get the dimensions from the machine and create a 3d model of it in the future.

[spalm]

Good job sir. You are a thinking man. This will be fun to watch come together.

Your triple bearing with a center eccentric looks great. I guess this will be a gantry style machine? If your gantry is strong enough, you may not need (or want) those horizontal bearings on both sides.

Some more close-up pics of your eccentric would be nice. Also the "simpler method" you eluded to.

Is that snow on the ground in the background of the pics in post #4?

Steve

[Sanghera]

Thank you. The simpler method would be to get a short 3/4 inch bolt and drill a hole through it lengthwise. The hole would be 1/8" off of the center of the bolt if you want it for a 3/8 inch screw. This method I have not tried yet, I made mine on the lathe and after some hours of work, my Dad told me that it looks like a bolt with an offset hole in it. I sort of complicated things, but I think my method turned out just as good if not better. I will post some pictures of these later. It will be easier to visualise what I am talking about. Can you explain what you meant by not having the bearings on both sides?
Thanks
Sanghera.

[ViperTX]

Personally I would simplify it by removing the middle bearing....

[Sanghera]

I'm not sure if I understand. Without the middle bearing there is no adjustment, or tension to hold the other bearings solid to the bottom of the channel.
Sanghera

[acondit]

As I understand it the two end bearings press against the bottom rail and the middle bearing presses against the top rail to prevent lift. The middle bearing is adjustable to control the amount of tilt allowable (hopefully none).
And if I understood Joe's suggestion correctly, he was suggesting that there be an adjustable bearing near each of the end bearings. That would have the effect of further minimizing any tilt due to the distance from the bottom riding bearing to the top riding adjuster. Did I get that right Joe?

Alan

[spalm]

Sanghera, I believe that I posted in error. Yes you do need horizontal bearings on both sides. My mind was somewhere else. But it seems to me that you need one side adjustable, as with your eccentrics on the horizontal bearings.

Sorry for the confusion,
Steve

[ViperTX]

Oh, now I understand what you're doing.....you're using the middle bearing to pre-load the outer bearings against the bottom of the channel.....well crap.....worse then I expected.....anytime you have any rotational force.....the thing will act like a pendulum.......you need to add 2 bearings...and have them close to the outer bearings.....and not in the center....

[Sanghera]

hmmm.... I can add another bearing to join the middle one. as in , riding against the top to push the others down. this will make two and two bearings. this should stop any possiblility of rocking. For some reason I don't feel any play whatsoever. And it all seems to be working very solid. First I will try the machine the way it is then see if I really need to change, which I might. I have painted everything and thought everything was good. Oh well, I'll just have to see tomorrow. Also, check this out :
http://www.bwc.com/html/utilitrak.html . They have the same method of three wheels. It should be able to handle rotational force.
Sanghera

[svenakela]

Your bearing and wagon-idea is similar to my home made X-axis.
I have boggie-mounted bearings on all four sides, in both ends. This means I have 16 bearings per wagon, I can tell you it's stuuurdy!