[jamont]

Yesterday I tried using a 6-32 tap to make threads in a Hammond 1455 case so that the self-threading screws that Hammond supplies could be replaced with a standard machine screw. Although this more or less worked, it seemed like the 6-32 tap was a little small for the groove in the case. So I'm wondering if there is a metric size that might work better. Has anyone tried this?

 

[phaedrus]

I've used an 8-32 tap on the hammond cases. It seems to work well, but cuts into the lid/base panel. Once the threads are cut, I clean up the panel with a deburring tool.

 

[Nisbeth]

I take it that you mean 6/32 of an inch?
If so, the outer diameter is ~4.76 mm. The 8/32 the has a outer diameter of 6.35 mm. Both M5 and M6 screws will be in between then (5 and 6 mm outer diameter respectively), and should be reasonable easy to get hold of. M5 is probably your best bet (for a start at least).


/U.

 

[chosen1]

I drill out the "hole" with a #29 drill, then run a 8/32 tap in it. It helps to use a cutting fluid as taps are very brittle. If you do it this way it will cut threads on the lid/base so it is best to mark the orientation of the lid/base with the rest of the case so it always goes together the same way.

 

[tangent]

Quote:

I've used an 8-32 tap on the hammond cases.

Me, too. I drill out the hole a bit, tap it out, and then grind off about 1/16" of the edges near the ends of the slide-in panel to allow room for the wider screws.

Quote:

I take it that you mean 6/32 of an inch?

No, it means it's a #6 size shank, 32 threads per inch. It's an American screw dimension.

 

[jamont]

OK, it looks like 8-32 is the next thing to try, I picked up some taps and screws on the way home tonite.

Thanks to everyone that responded!

Update: I tried the 8-32 and that looks like it will work pretty well. Since #8 screws have somewhat larger heads, I'm thinking I'll use a socket head screw, rather than a countersunk screw.

 

[jamont]

A photo of my PIMETA assembled with 8-32 socket button screws is shown
here

 

[Voodoochile]

That looks WAY better than the faux screws that Hammond supplies!

Nice job, John.

 

[aos]

What is #29 drill? I thought american system uses inch sizes (all drillbit sizes that I've ever seen in a store were specified in inches). I found somewhere on the web that #29 drill is .1360" which doesn't correspond to any of the inch fraction sizes that I've seen - that's between 1/8 (0.125) and 9/64 (0.1406). Please don't tell me that Americans have two drill bit size systems

.

Another question is, what kind of screws are to be used after tapping with 8/32? There are the ones with nuts - which I can't see being used because there's no way to hold on nuts while screwing it together since the nut is inside the (closed) box. That would leave metal screws like the ones already shipping with the case - but I thought those are generally self-tapping so that taps are only made for nut & bolt type stuff.

 

[chosen1]

Yes you are correct. A #29 drill is .1360". Yes we do have two drill bit size systems. Most people don't know about the number drills because they are used primarily by machinists, toolmakers, etc.
To answer your other question, you would thread an 8/32 screw into the hole as if the hole was the nut.

 

[aos]

Quote:

To answer your other question, you would thread an 8/32 screw into the hole as if the hole was the nut

That makes sense. I wasn't thinking straight.

Quote:

Yes we do have two drill bit size systems.

That, however, doesn't. I can only hope that hardware stores carry number bits.

 

[jamont]

Quote:

Originally posted by aos I can only hope that hardware stores carry number bits.

I got an 8-32 tap and #29 drill bit packaged together for about $4 at Lowe's .

Some useful information is available here and here.

 

[aos]

Thanks for the info, I'll visit Home Depot or something like that tomorrow. As you can see, I'm somewhat mechanically challenged

. I couldn't even find that info through Google.

One more question, how long are the screws you guys used? I only found 1" ones today, and that looks like it's much longer than required. Selection at Home Hardware wasn't very good.

 

[jamont]

I used1/2", that was a little longer than necessary, 3/8" would probably be about right.

Screws are very expensive in small quantities at places like Home Depot. If you settle on something you want to use in quantity, order a box of 100 from BoltDepot or something similar. The screws in my photo are high quality stainless steel and were 7 cents each ar BoltDepot.

Unfortunately, BoltDepot ships only to US customers. A similar place that will is Micro Fasteners (but I have not tried them).

 

[aos]

How do you tap? Somehow I don't think that I'm supposed to use tap with a drill... or am I? The end of the tap is square, not round, implying yet another kind of tool...

By the way it seems that #29 or any numbered drills are a real rarity. Even the stores the size of two soccer fields don't carry them. Luckily Home Depot bundles #29 drill with 8-32 tap so I got that.