[ginettaman]

Hi,
I'm casing up my PPA in a Hammond enclosure 1455N1601 and see some of the builds use nice Stardrive/Allenhead type fittings to hold the end panels on.

Can anyone tell what size they are, and also does the case have to be tapped, or will they cut there own thread in the aluminum?

Thanks.

 

[amb]

Quote:

Originally Posted by ginettaman Hi, I'm casing up my PPA in a Hammond enclosure 1455N1601 and see some of the builds use nice Stardrive/Allenhead type fittings to hold the end panels on. Can anyone tell what size they are, and also does the case have to be tapped, or will they cut there own thread in the aluminum? Thanks.

I use 6-32 socket cap machine screws, and I do need to tap the threads.

 

[bhjazz]

I used the 6/32 x 1/2" also, but just jammed the screws in and they tapped themselves since the aluminum is softer than the stainless steel.

 

[bryman79]

Quote:

Originally Posted by bhjazz I used the 6/32 x 1/2" also, but just jammed the screws in and they tapped themselves since the aluminum is softer than the stainless steel.

Machine threaded screws will not self tap. The threads must be cut, which is the function of a tap. Even the sharpest stainless screw will not cut, as there is no place for the chips to go. You likely swedged the material apart, which is bad for a number of reasons. This is also what happens with the stock Hammond screws, which were a poor design choice to begin with. I've lived with stripped threads up to this point, but I'll have to take AMB's suggestion and tap the threads next time...

Regards,
Bryan

 

[nikongod]

as mentioned, the screws there...

if you dont need a eurocard size case, the lmb-hegger cases are also quite nice... they tap for 4-40 screws. this is nice because they are more likely to sit flush with a thinner endplate.

 

[bhjazz]

Quote:

Originally Posted by bryman79 Machine threaded screws will not self tap.

Well, maybe so...but so far so good! The threads are not stripped, and the screws stay in as well as I would have expected. You do bring up a good point, though!

 

[StevieDvd]

Anyone have an idea of what the metric sizes are M4, M5 etc?

Would like to get a thread tap and some socket head screws/bolts to replace the screws on a few hammond cases.

 

[Nospam]

The metric size refers to the diameter of the fastener shank/thread.

Some common sizes I found at Mcmaster.com are: M1, M1.2, M1.4, M1.6, M2, M2.5, M3, M3.5, M4, M5, M6, M8, and M10

BTW, am I the only one that thinks it would be better to use inserts? I've seen too many instances of stripped threads in bare aluminum parts. Of course, installing inserts is a bit of work, and I guess there may not be enough room in some cases... I guess I sort of answered my own question

 

[Nisbeth]

Quote:

Originally Posted by StevieDvd Anyone have an idea of what the metric sizes are M4, M5 etc? Would like to get a thread tap and some socket head screws/bolts to replace the screws on a few hammond cases.

I reasearched this a while back but I have never tried it, so I take no responsibility for damaged enclosures, tools and/or limbs

You might be able to tap the hole almost directly to M4 (i.e. without drilling the hole to 3.2/3.3 mm first), but I honestly don't think so. Drilling the hole to 3.2 mm is a bit risky. The drill can easily get stuck and break because the diameter is quite close to 3.2 mm already. If I were to try, I would drill the hole out to 4.2mm and then tap it for M5. Note that the holes in the front panel are too small for an M5 so you have to enlarge those as well.

/U.

 

[StevieDvd]

Thanks so if the tap & die set does M4 & M5 I'll be OK and a selection of M4/M5 socket headed bolts should see me sorted.

Thanks

 

[steinchen]

drill diameter = 0,8 * taper diameter

M3 2,4 mm
M4 3,2 mm
M5 4,0 mm

put one or two drops of oil into the drilled hole before you tap

 

[Nisbeth]

Steinchen, you're probably right but the drill diameters apparently depends on where you look

What I've seen are:

M3: 2.4/2.5mm
M4: 3.2/3.3mm
M5: 4.0/4.2mm
M6: 4.8/5.0mm

When you drill/tap aluminium, alcohol (white spirit?) works well as cooling fluid/lubricant

/U.

 

[steinchen]

you're right, the *0,8 is only a rule of thumb but precise enough for most cases, 0,1mm won't make much of a difference

to be exact:

metric ISO tapering DIN336 for standard tapering:
M2,5 2,05mm
M3 2,50mm
M3,5 2,90mm
M4 3,30mm

metric ISO tapering DIN336 for fine tapering:
M2,5 2,15mm
M3 2,65mm
M3,5 3,15mm
M4 3,50mm

I doubt that anyone of us has such a fine graded set of drills, so a practical rule of thumb is
drill diameter = (taper diameter * 0,8) + 0,1