I made a ham radio go-bag with the connections and switches mounted into a panel. I used HDPE and cut holes in it, but my square holes were crap. I tried a dremel with a router attachment. I tried a coping saw and didn't have much better luck. It looks bad and I'm not happy with it. I tried an aluminum plate and my holes were worse.

I'd like to find a company that does one-offs and prototypes with a CNC machine. Anybody know a source for one-offs and prototypes that can cut some holes in a piece of aluminum plate?

This was the first iteration.

Chassis punch.

All you will ever need.
http://www.frontpanelexpress.com/

I looked into that - it's a great solution. The least expensive I found was about $85 each, and for the four sizes I needed, it seemed like too much to spend for one project.




That's what I'm looking for. Have you used them before?

And you think paying to have it done on a CNC is going to be cheaper?

For cost comparison sake, material costs alone it takes $150/hr to run our waterjet, then you pay the operator and his programming time... That part will take probably 15 minutes out of AL (5 minutes on HDPE). But most shops have a minimum charge.

For this sort of job you don't go to a machine shop - you find someone with a small gantry CNC router that is a hobbyist.  OP should see if he is near any sort of Maker Space work shop.  Most big cities have them now.
Those panels can be fairly easily drawn on sketchup then converted to g code, with sketchucam.
He may be able to find some help on OpenBuilds.com.

That frontpanel web page quoted about $65. I had it drawn in AutoCAD, but they had a simple sketch program so I drew it in about twenty minutes. I

One way to do this is as follows:

Make a jig.

It consists of four (typically straight) sides and a way to clamp it to the work piece.  Sounds like work but it's easy to make and easy to use.

Get a router bit with a bearing.

A guide bushing also works.  Look them up in a catalog or online.  They may also be called a template cutting bit.  The jig has to be designed for the bearing/bushing you buy.

Use jig to guide the bearing as the router runs.

Once clamped to the work piece, just run the router around the inside of the jig, keeping the router up against the sides of the jig, and you will get the nice, clean hole(s) you desire.

If you need square corners, you will have to create them after cutting out the rest of the material.   But first, ask yourself why you have to have square corners.


The holes for the buttons and switches get drilled, just as you have done.  


Personally, I don't think chassis punches are the way to go for large holes in thick material.  I think they are for punching relatively small holes in sheet metal.

NOT a good idea.

The cutting geometry for wood router bits is not the same.

While metal cutting bits can do wood (and have been used for plunge cutting and mortises for a while) using a wood bit on metal is a bad idea.

I built jigs to get it cut to size with a jig saw and metal blades. I've been saying that I need a router for quite a while.

The Greenlee knockout punches I saw would do 1/8" aluminum sheet for the 0.75"x1.25" holes I needed.

He's using HDPE.

What hole sizes are you cutting?  Are they small holes for switches or a big cutout for the radio and mic?

His holes have square corners. Show me a CNC router that can cut square corners.

To get square corners it's going to have to be a waterjet, laser, etc. How many hobbyists have those? The costs of said devices are well over $100k even for cheap, entry-level stuff.

A file will make short work of squaring off corners.

A few strokes with a triangular file will leave as tight an inside corner as you care to produce.

It certainly would, but he specifically asked about CNC work, which implies he wants a "turn-key" type of solution.

If he wanted to use a file then why not just jump 1 more step and do the whole, drill 4 holes, use key-hole saw to cut, then file to final shape? That would completely eliminate the need for him to take it anywhere else.

Another option (if he's going to file corners square) would be to find a hobbyist with a mill and manually mill the holes out then the OP can file the corners. His odds of finding a hobbyist (that will work cheaply) with a mill are MUCH more likely than finding a "hobbyist" with a CNC laser or waterjet simply because of the cost differential between the machines. You have a small, manual mill that can be had for $500-4000, or a large, industrial machine that can be had for $100,000-1,000,000. You aren't going to find the latter in the hands of a "hobbyist" unless he's a millionaire that was just looking to blow some money.

My point was that I don't understand what his real purpose is. Is he trying to get somebody to give him something for nothing (CNC work for less than the cost of the chassis punches that were suggested to him)? Looking for advice on a different way to do it (he didn't ask that)?

I'm not trying to be a dick, just pointing out that if he really is trying to chase down legit CNC sheet-metal work (as the OP implies) it's not going to be as cheap as he thinks. That being said, the part cost on this gets dramatically cheaper if he wants 100 of them vs. a single copy because it saves on the machine programming time and the sheet load/unload etc. Just a guess here but I bet if he took a completed dxf (does the OP have CAD so he can do his own dxf?) to a shop with a waterjet he could probably get one of these made for no less than $200 unless the shop was hungry for work.

I did the corner drill and file routine and it did not come out well. Probably because "rush" is the only way I get stuff done in the limited time I'm allowed to do my projects around all the little kid stuff. It worked well enough, but I thought it looked like crap. I was hoping for less than $100 for a CNC solution that looked and worked better because more than that would indicate some other DIY solution. If it turns out (it didn't, according to that web site above and if I use a CC and get no delivery, I make the CC do the dirty work) that a CNC option is more expensive than a router and a table, I'm OK with that.

I understand you're not trying to be a dick. I wouldn't know the permutations and complications unless I asked.

Thanks to everybody who answered. I'm glad to know that the stuff I tried was completely a failure of my own.

If you can get a dxf (basicially a simple, flat profile CAD drawing of the shapes you want) drawn up you will have a lot better luck finding somebody to take this on. Most shops won't mess with a one-off where they also have to make the dxf & cut files from a paper-napkin sketch. If you have the dxf they can just import it into their computer, generate the cut file automatically, and push the go button. That makes the difference between 5 minutes of operator time and 2 hours of operator time. IIRC google sketch-up will do dxf files; you may want to consider that and once you have the dxf in hand send it out for quote to a few shops. Maybe go to practicalmachinist forum or home-shopmachinist forum and ask if anybody would be willing/able to make a one-off part. The key to getting this done cheap is to find somebody that is hungry for work. The guys that aren't hungry won't even respond to you (they're busy); the guys that are hungry will likely respond.

Hey op. If its just the connections panel shown, I would be happy to cut one out. PM me.

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CNC work rarely can eliminate ALL handwork.
Even a laser has a diameter.

Few things have infinitely perfect square on their corners also.

I don't understand what you're getting at.

The diameter of a laser or waterjet is drastically smaller than that of a commonly used end-mill for such purpose, to even equate the two is asinine. There are reasonably acceptable corner radii in square pockets/holes, in this case I believe that radii is quite small, to the point that laser/waterjet would be turnkey but mill would require significant time. And yes, while waterjet and laser parts may require deburring (application dependent), that is NOT the same as milling the holes and filing the corners square. The deburring on a waterjet or laser is so routine that most operators can deburr parts AND program future jobs WHILE the next job is running. With the number of holes in that plate you're talking about hours of filing the corners out. I do this stuff for a living EVERY DAY. I'm not trying to be a smartass but it seems you have taken quite a bit of issue with the advice I gave. Are you offering your services to the OP at cut-rate prices? Are you going to sit around and file the corners out for him after it's milled with a 1/2" end-mill?

What is the point of even offering the advice of using a mill here? As I pointed out above, if he wants to do it with a great deal of manual labor he can totally skip the process of locating/paying somebody to cut the pockets on a mill and he can just drill a hole at each corner of each pocket, cut the pocket, then file the corners out. I don't believe he WANTS to do that because he is asking for other advice; I don't blame him, that would be an all day project to do...

There are occasion that require an actual perfectly square corner.

You still do some hand work when you need one.

Smaller is not zero.

It may be tight but it is still not square.

You stick a gauge block into the corner to check (and not a regular 'wring-able' gauge block).

There are actually blocks made for checking corners.

And your point?

I guaranteed that this is NOT a situation that requires a truly square corner; anybody that knows about this stuff could look at the design, realize what is being accomplished and what is going into those holes and know right from the start that it's not necessary so why would it even be brought up?

This whole thread is starting to boggle my mind... simple thread turned complicated... why? Why over-complicate things?

I would say that trying to CNC a simple front panel is way over complicated.
In almost any material.

CNC and automated are rarely the answer for 'one offs.'

I dunno about that.  I use Autocad all day long, and I do the majority of the programming for the CNC router at work.  Given a file to work from, I could create a toolpath for that face plate in about 5 minutes, 10 total if you cout the pre-programming Q&A.  Setup for plastic would take another 10 at most, and tack on another 10 for cut time and handling.  Shipped raw and rough, 30min OTD.  Smoothed and finished, maybe 10-15 minutes more depending on material.

My point is that CNC programmed tools used to be complex and, like you said, maybe not the best choice for a single piece.  These days, not so much.  I do one-off items all of the time.  Many times it is much easier to do the planning on my computer and then let the machine do the work.

Tell that to the shop I work for; 90% of our workload is prototyping and production quantities of 1-10 of each item. We have 6 vertical CNC machine centers, 1 large cnc horizontal with another on the way, 3 CNC lathes, cnc waterjet, cnc laser, & cnc sheet-metal break. Anytime we get a request for large production quantities it gets contracted out to a shop better suited for full rate production.

I understand that CNC isn't the most economical option, which is what my posts alluded to very early in this thread... but that is what the OP was specifically asking for.

Do you have a college near you that has a Machinist class?  If so, talk to a professor about having a student make one for educational purposes.  You supply the material...which would probably be the only cost.

I took a "Intro to CNC" at my community college when I went for ME and Welding...

I take it for granted more than I should...but I have a friend that works at a laser-cutting place.  He pulls stuff from the scrap pile and makes me whatever I want for free