How to position a pre-made panel to accept holes?

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tomb18
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How to position a pre-made panel to accept holes?

Post by tomb18 » Sun Dec 20, 2015 5:09 am

Ok, I've got some project boxes, and these boxes have end panels made of aluminum. Each panel has 4 screw locations that are already present. These could be used to bolt down the panel for mill work.
Now, I need to make some holes and squares in this panel at precise locations. So how would you do this?
I can thin k that I know the dimensions of the holes in the panel so I could have the shapoko drill holes in the wasteboard and then I would screw in the boards. I guess that's one way but I would have liked to have captive nuts so as to make the boards location more precise.
Can anyone suggest the best way to go here?
Thanks

WillAdams
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Re: How to position a pre-made panel to accept holes?

Post by WillAdams » Sun Dec 20, 2015 9:26 am

Easiest way:

- add a spoil board
- drill centered holes w/ countersinks for hardware on one side
- flip board over and mount it
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tomb18
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Re: How to position a pre-made panel to accept holes?

Post by tomb18 » Sun Dec 20, 2015 5:52 pm

Hi
Ok I guess I'm missing something here...how do you get the zero point for the mill so that it cuts in the right place??

Estlcam
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Re: How to position a pre-made panel to accept holes?

Post by Estlcam » Sun Dec 20, 2015 6:42 pm

tomb18 wrote:I can thin k that I know the dimensions of the holes in the panel so I could have the shapoko drill holes in the wasteboard and then I would screw in the boards.
That is the best approach and very precise if done right:
  • Drill the holes in the wasteboard the same size as the holes in your aluminum panels and then put identically sized pins into it (don't use the holes to screw the panels down - use them just for alignment).
  • 2 holes are enough for alignment - just take the two furthest apart from each other. More pins won't improve accuracy.
  • If you need to use all holes to screw the panels down make sure screw diameter is as large as possible to minimize play.
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GoSpeedRacer
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Re: How to position a pre-made panel to accept holes?

Post by GoSpeedRacer » Sun Dec 20, 2015 7:10 pm

tomb18 wrote:Hi
Ok I guess I'm missing something here...how do you get the zero point for the mill so that it cuts in the right place??

to make it repeatable you will pretty much require a homing system, a few people on here are making limit switch kits that will save you the time and effort. The first cut will be for the pegs or screws into the waste board. After that, bolt down the material and adjust the height of the Z axis, and if homed properly it will always repeat

tomb18
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Re: How to position a pre-made panel to accept holes?

Post by tomb18 » Sun Dec 20, 2015 8:10 pm

Ok,
I'm a real newbie here...
Now I get it.
I take a small piece of scrap wood each time. I clamp it to the table. I set my zero point close to the wood and then run my job which has 2 holes for position. I then pause, and put two pins in there and then the piece. Clamp it down and then continue the job.

When I want to make another, I do it all over again.
Right?

Thanks

WillAdams
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Re: How to position a pre-made panel to accept holes?

Post by WillAdams » Mon Dec 21, 2015 12:00 am

My understanding was that the stock had pre-drilled holes --- my suggestion was to drill matching holes, then fasten the stock in place. You’d probably want homing switches though, or use “poor man’s homing”.

http://docs.carbide3d.com/article/39-ho ... e-switches
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cvoinescu
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Re: How to position a pre-made panel to accept holes?

Post by cvoinescu » Mon Dec 21, 2015 12:40 pm

Homing switches are of great help for this type of job. You can do it without them, but, if you need to do more than a couple of parts, it's simply not worth it.

In addition, a lot of machines have a 90 degree angle (or two separate straight pieces) attached to the front-left side of the table, as a simple and versatile fixture. You can set the default work coordinates to have the corner of the fixture as their origin. Then, you place the part you need to machine flush against that corner. This gives more accurate alignment than just using the screw holes, although that can be quite good too (especially if you use machine screws into inserts or tapped holes, not wood screws).
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veng1
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Re: How to position a pre-made panel to accept holes?

Post by veng1 » Mon Dec 21, 2015 11:41 pm

You stated that you needed to make cuts at precise locations:
- How precise from each cut to the other?
- How precise from the holes?
- How many total parts do you want to do?

I do a lot of this in my business, so this is how I'd do it:
Install homing switches.
Clamp a spoil board where it will not move through the entire job.
Measure the existing holes and drill two corner holes the size of the existing holes which hopefully are a standard size.
Align the work piece to the holes with roll pins/spring pins:http://www.mcmaster.com/#roll-pins/=10c9vdy I normally use 1/8" because that is what is used for PCBs.
If you are going to build a lot of them, toggle clamps are a good way to hold the piece. Get the ones with rubber bumpers. I prefer Carr-Lane but these will work http://www.mcmaster.com/#toggle-clamps/=10ca0tk Make sure the cutter path doesn't hit the toggle clamp.

If for some reason the homing switches or the spoil board gets moved, start over. I, at least, have never gotten one back in position accurately. I just drill new holes.

For quick and dirty, I use the Shapeoko to drill pilot holes and use wood screws.

For the primary thing I build lots of, I have a fixture made from aluminum extrusion that is firmly bolted to the frame of the machine that aligns the work. It won't move unless its hit by a truck. It's always there and then I put an entire new spoil board on top of it to do anything else.

tomb18
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Re: How to position a pre-made panel to accept holes?

Post by tomb18 » Tue Dec 22, 2015 12:05 am

Ok, Lots of good suggestions! I'll try and do this last one. Oh I wish McMaster Carr shipped to Canada!!! One of the few companies that doesn't!

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