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Old 10th Feb 2019, 4:24 pm   #21
m0cemdave
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Default Re: Using hole punches on die cast boxes

Steve has got his answer (step drill in press) and hopefully a successful outcome.

But I can add that I have used Q-max cutters in diecast boxes for years. Although the circular cutout piece always disintegrates, which is useful because it's easy to clear from the tool afterwards, I don't think I have ever broken a box or lid.

I wonder if there is wide variation in the quality of diecast boxes, or at least in the mix of alloys used? Or maybe it depends on how sharp the cutter is?
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Old 10th Feb 2019, 4:33 pm   #22
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Default Re: Using hole punches on die cast boxes

I've used Qmax cutters for D-sub connectors in diecast boxes. Results have varied from nice metal that takes a clean shearing cut to stuff that crumbles and in-between is stuff that radiates tears from the die/punch.

Tapered reamers work nicely in diecast boxes, even the very zinc-y ones. the force is applied outwards, in the plane of the surface being cut.

Diecast boxes vary.

David
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Old 10th Feb 2019, 5:00 pm   #23
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Default Re: Using hole punches on die cast boxes

I've used Q-Max cutters fine on diecast boxes, Eddystone brand (now Hammond), 3/4" for B9A valveholders and also 9-way 'D' connectors, no problem.

As others have said, the waste, punched-out bit comes out in pieces. But the hole itself has always been fine.
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Old 10th Feb 2019, 5:04 pm   #24
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Default Re: Using hole punches on die cast boxes

I've used q max cutters and step drills with no problem on die cast boxes and aluminium.

However on thicker materials (2mm) I find the diameter of the hole is slightly different on each side when using a step drill as even they have a small taper.

I only use cone drills / reamers for de-burring.

Never in 50 years of using q max cutters have I had trouble punching holes in die cast boxes plus I'm still using the same q max punches - must have been well made !

I always use step drills at the minimum speed in my drill press.

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Old 10th Feb 2019, 7:08 pm   #25
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Default Re: Using hole punches on die cast boxes

Last ones I did I cheated and used my CNC mill
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Old 11th Feb 2019, 2:39 pm   #26
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Arrow Re: Using hole punches on die cast boxes

Quote:
Originally Posted by Radio Wrangler View Post
Die-cast boxes vary.
Exactly: the constituents of 'die-cast metals' (as per this thread) are not all the same. The following Website tells us quite a lot about die-casting: metals used, mechanical properties, etc.

https://www.dynacast.co.uk/die-cast-metal-properties

Al.
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Old 11th Feb 2019, 8:07 pm   #27
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Default Re: Using hole punches on die cast boxes

Quote:
Originally Posted by Refugee View Post
It is not unknown for step and cone drills to be seen on sale in Aldi too at an equally competitive price as Lidl do them for.
I spotted them a week ago and bought some.
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Old 11th Feb 2019, 8:09 pm   #28
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Default Re: Using hole punches on die cast boxes

I have to say I've used q-max punches 20 or 25mm in diecast boxes many times without any problems, and yes the waste bit breaks up.

A hole saw would be better if you're still not sure but it wouldn't bother me.
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Old 12th Feb 2019, 4:39 pm   #29
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Default Re: Using hole punches on die cast boxes

I've been using Q-max punches on die cast aluminium boxes of various makes, Eddystone, RS, Hammond and possibly others for over 50 years and never had problems with the box cracking. I have a set up to 50mm and I don't think I've had any trouble up to at least 35mm; I'm not sure I've used the biggest ones on die cast boxes.

I don't often use the ordinary hex (Allen) keys but usually 3/8" square drive hex bits and a ratchet handle. As advised in the instructions, adequate greasing of the punch and screw is useful.

I have however had reports of curved castings of street lighting lanterns cracking when using screw-up punches but I couldn't be sure of the care/skill/experience of the operator. This was in an attempt to avoid the crude, uncontrolled holes when using a cone drill.

Hole saws are effective but less accurate than screw-up punches and if used in a hand drill, the drill must be fitted wth a side handle to avoid serious injury.

PMM
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Old 16th Feb 2019, 2:46 pm   #30
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Default Re: Using hole punches on die cast boxes

Well, I decided after all to try the punch and...success. No damage to the box and nice clean holes.
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Old 16th Feb 2019, 4:04 pm   #31
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Default Re: Using hole punches on die cast boxes

Very nice holes.
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Old 16th Feb 2019, 4:06 pm   #32
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Default Re: Using hole punches on die cast boxes

6sl7 / 6sn7?
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Old 16th Feb 2019, 5:55 pm   #33
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Default Re: Using hole punches on die cast boxes

The box is for one of a pair of mono power amps using 6SL7 and 2x6V6, based on a Dynaco 10w circuit.

It uses a readily available PCB - just search for "Dynaco 6V6/EL84 6SL7/12AX7".
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Old 16th Feb 2019, 7:30 pm   #34
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Default Re: Using hole punches on die cast boxes

Quote:
Originally Posted by g4wim_tim View Post
I've used q max cutters and step drills with no problem on die cast boxes and aluminium.

However on thicker materials (2mm) I find the diameter of the hole is slightly different on each side when using a step drill as even they have a small taper.
The trick here is to do the first bore with a cone-cut from one side of the workpiece then follow up with a second bore from the other side. Then your hole - when breached - is equally-chamfered from either side, with the narrowest part being half way through the material.
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