Drill jig advice

[MrStab]

Hi!

I really need advice on something: I need to drill two 22mm XLR cutouts and their corresponding drill holes, with a high degree of precision, for 2 board-mounted XLR sockets. In 2mm-thick Hammond 1590* die-cast enclosures.

Until now, paper templates and glue have been fine, as there's been some room for slight errors when washers and CNC-cut panels are involved. Even singular XLR sockets or multiple board-mounted 1/4" sockets can be managed as such, but this isn't the case with more than 1 XLR socket. Accurately drilling 2 is HARD!

I have an industrial drill press and currently use a cone/stepping bit. I have no idea what route to take. I can afford something custom-made, within reason.

In my limited understanding from reading past posts here, I assume the ideal jig is a piece of metal with the appropriate hole sizes and positions, whose material isn't easily-drilled. If so, does this necessitate standard drill bits of a fixed size? How does the jig cope with and guide a rigid drill press into position?

Or is there a different approach? The internet is saturated enough on the matter to confuse me about which route to learn about.

Thanks for any help!


-Grant

[blackieNYC]

A Greenlee punch?

[MrStab]

Thanks! Would that work for Hammond 1590* enclosures, with their 2mm thickness? Sorry, should have said - will update OP.

Upon watching a YouTube vid, I'm not too sure if singular knockout punches would help get the holes the exact right distance apart. I can drill em, it's more a case of ensuring correct alignment I guess.

[PRR]

22mm XLR cutouts ..., for 2 board-mounted XLR sockets.

Change your plans. Wire-connected sockets is more labor but a LOT less alignment headache and scrap.

[drdn0]

Sounds like the perfect introductory project for teaching yourself CAD and 3D printing

[stallik]

If this is a one off, mark box as you use to, drill too small, finish with file.
A few boxes, flying leads
Full production, CAD

[Elektrojänis]

One thing that might help a bit if your box layout allows is to solder the connectors and pots on the board in the box. Put the box-mounted parts in their holes. If you put the nuts on, don't tighten. Fit the board in to the parts and then solder them in. After this you can tighten the nuts.

Usually there is a bit of wiggle room on the board mounting holes, but when you solder the parts in they are locked. That's why this could help. Actually, that wiggle room could work against you if you solder the parts on the board without the box.

This ofcource only helps if the board is placed in the box in an orientation that makes it possible to solder on it in place.

[Phend]

I've been making acrylic hole locators. Also use faceplate, so you see them attached with button head screws. Plus various fixtures to help assemble the board mounted pots. One box need a 2 inch +  hole with 4 attachment holes, each in some odd location. Used a scroll saw to make big hole. The 4 screw holes needed some rat tail file work. Here are 2 different ones.

[MrStab]

Thanks for the replies!

I have FreeCAD models, and it's for production. More labour isn't too ideal as it's just my overworked self doing it, with a few pedal orders each week to get through. That said, outsourcing to Hammond or whoever probably wouldn't be too cheap and would cut into margins.

How could I translate CAD to drilling alignment in a reliable way?

As it stands, I can't reach the solder joints as the sockets are horizontally-mounted, but I may redesign to be vertical-mount (as standoffs allow reinforcement when plugs are inserted, albeit with added risk of board flexing). So post-insertion soldering is an option which makes sense to me.

Faceplates are an idea I'm considering (would be handy for labels, too), but going for 23mm holes instead of the bang-on 22mm puts the edges far too close to the mounting screw holes for comfort.

Some slight teething issues visible below lol:

[Phend]

You might consider a hole saw to make big holes

[bluelagoon]

Why not check out Tayda Electronics for their very good reliable and accurate drill service, at least you would get the 2 xlr holes in exact alignment and separation distance to each other. And the service is not that expensive, and while getting the xlr holes cut you could also get the rest of the enclosure cutouts done, or any line cuts like as in rectangles etc. You could also get the enclosure graphics done at the same time.
And think of all the time saved and cash saved from buying expensive cutting tools and doing the job yourself.

Enclosures and Drill Service

[MrStab]

I'm not totally averse to off-brand 1590 enclosures, but I recently tried a few of Tayda's pre-painted enclosures, and I wasn't happy with the quality of their 1590A's for a number of reasons. The 1590B's were fine. They don't seem to have the required 1590T.

Nonetheless, maybe I should shop around for such services from other distributors.

[amptramp]

The standard cast box has a draft angle of 3 to 5 degrees to permit removing the box from the mould.  You have to decide whether you want to drill perpendicular to the board or to the sidewall.  They will have a 3 to 5 degree difference.  This is one case where you could wire from the board to the connector and drill perpendicular to the side.

[MrStab]

You have to decide whether you want to drill perpendicular to the board or to the sidewall.

The I/O board is mounted to and therefore aligned with the sidewall (unless I'm misunderstanding!)

I'll try to learn how to actually modify CAD models over the weekend, to send to services - tips welcome on that, too.

[MrStab]

Surely there's a tool you can mount two drill bits into and have them turn simultaneously? That doesn't sound too insane. But then that's exactly what an insane person would say.

[mozz]

Id be inclined to keep using your paper jig, just use a punch spot so your bit doesn't walk.  Drill everything a bit oversized so you have some slack. 

[marcelomd]

Hi,

Last time I wanted to drill a few aligned holes I ordered an aluminum "PCB" with guide holes. It was $2 or $4 from JLC, I don't remember. I used it as a jig:



It's for a 10 knob preamp. The small holes are drill guides. I just tape the jig to the enclosure and drill the 10 holes with a 3mm bit. Then I remove the jig and use a step drill to make the holes the right size (7mm).

The large holes I use to hold the potentiometers while I solder and to test the circuit out of the box.


Another alternative is to disassemble a XLR connector and use it as the jig.

[Phend]

Gang Drill

Before that, back in the old days, we had a layout department. They used blue dykem layout fluid.
Brush in on, dries fast, then with a machinists scale and a scribe, measure to the hole location within +/- 1/64 inch. Draft? bump the box up against a "square metal block" and measure from that datum. Holes in the machine tool industry are usually located +/- .0056 inch, ansi Y14.5. That is for assembly of 2 parts.
Anyway, for stomp boxes, where you can oversize clearance holes, 1/64 is plenty good. Get a nice machinists scale, scribe, magnifier and blue dykem. And do it the ole fashioned way.
 (correction 1/64 not 1/16)

[mozz]

You can adjust resistors yourself too, the old fashioned way, but i doubt anyone is going to do it. Anyone besides PRR know what i am talking about?

[diffeq]

You can adjust resistors yourself too, the old fashioned way, but i doubt anyone is going to do it. Anyone besides PRR know what i am talking about?

Filing into the resistor's body makes the resistance go up. Don't know the way to adjust down.

On topic:
marcelo's drill guide, taped with double-sided tape, has helped me on similar tasks. So did slightly oversizing holes and soldering jacks in situ, with solder pad holes large enough to give way in case of hole offset.