Ugh, LED mounting problems

So I'm trying to mount Vero 29s. I have used a 2.5m drill bit to create a hole and a 3m tap bit to thread. After doing this and testing a screw it drops in and only catches the threads when it's near the bottom of the hole which is where the threading tightens up. No good.

So where did I go wrong? I'm certain of the measurements. I thought perhaps they sent the wrong screws but I have some 2.5m screws from my last build and the new screws are visibly larger so they must be 3m right? Is a 2.5m drill bit too large for taping 3m holes?

Edit: I just drilled a new 2.5m hole and tried the 3m screw. It doesn't fit. I'm thinking maybe the tap bit is a little to large though the baggie it came in does state it's a 3mx.5 bit which is what I though I needed.

Edit: Now I'm thinking maybe the 2.5m drill bit was too large? I just tried another tap being careful not to wobble the bit and the screw just drops right down in there.

I've checked a couple charts and it's clear a 2.5m drill bit is used with the 3m tap bits. I'm at a loss, except maybe to try another brand of tap bit? The hole is too small for the screw before tapping, then too big after tapping.

SDS 's tapping way ...
(manually done ,by hand,no drill )

for mounting Vero29 :

-2.5 mm Drill (better the HSS / Cobalt type )
- 3 x.5 mm (M3) tap bit
-WD40 lubricant.

-Make a clean straight and perpendicular hole with drill.
DO NOT OPEN A THROUGH-HOLE AT THE HEAT -SINK.
YOU WANT THE TAP BIT TO STOP .

-spray some WD40 on the hole.
-Start tapping slowly . 1 and 1/2 turns inwards ,1/2 turn back (outwards) .
-Continue like that,until tap stops.
-Unscrew tap carefully.
-Clean and degrease the threads.

Cheers.

Are you using a drill press or some sort of jig to keep the drill bit straight?

SDS- you should try a cold form tap. No more in-out-in-out, no chips to clean up. Need a slightly bigger drill bit(2.8mm) though.

Yea, using a drill press, tapping by hand. I will try some lubricant and see if it makes a difference. Other than that I've done the same as stardust sailor. Thanks for the help, will update later tonight.

The lubricant makes a huge difference.

You'll get mixed opinions on which is the best lube for drilling/tapping aluminum. Some will say you need cutting oil and that WD40 is shit. Others will say that WD40 is the shit and that nothing beats it.

I've only tried WD40 and it's definitely a lot better than using nothing. It's like night and day.

Old timers use kerosene for aluminum so thats what I use.

churchhaze said:

The lubricant makes a huge difference.

You'll get mixed opinions on which is the best lube for drilling/tapping aluminum. Some will say you need cutting oil and that WD40 is shit. Others will say that WD is the shit and that nothing beats it.

I've only tried WD40 and it's definitely a lot better than using nothing. It's like night and day.

Click to expand...

I use PB blaster, seems to last quite a bit longer than wd40......but anectdotally, it seems to bind less then when using wd40 [hence the switch] but I am only one opinion

I have no idea what is going on since you are using the correct drill size. Only thing i can think of is the drill is so cocked that its drilling a bigger hole, or your misreading the drill and its actually the wrong size. If you can after drilling measure the hole with a vernier or if you dont have one just place the back of the drill the smooth half ibto thr hole and it should be a farely tight fit with little slop. That will determine if your drill is wobdering and drilling a bigger hole.

Using a "roll" tap eliminates the need to go in and out since it is not really cutting anything.

i never tap by hand i always use a drill press or a hand drill never stripped the piece or broke a tap. 20 yrs of being a tool & die maker and having a engineering degree may be helpful or I am just lucky.

also kerosene works best on aluminum and use bacon grease on everything else, unless it a unusual metal like magnesium, titanium, molybdenum etc etc .

also the gold coated "ti coating" drill bits and taps don't make any difference unless your doing piece work and doing 100s a day.
Cobalt drills and taps will make no difference on aluminum or other soft metals. All cobalt is a harder alloy then hardened steel.

i prefer carbide drills over any other very rarely need sharpening and cuts SS like a dream.
they can be costly unless you grind your own out of broken endmills or spare carbide punches.

I used some liquid wrench and then carefully tapped a hole. Success! Seems weird though because I didn't have this issue with the Vero 18s, which used 2.5m screws, and didn't use a lubricant though it would have been a good idea. I think maybe the larger hole is more prone to getting warped by an unsteady tap bit.

Using the liquid wrench I was able to tap by hand without any unscrewing, so I'm going to finish the job with a hand drill to make sure no wobbling occurs.

Could have been a much longer troubleshoot without this board, so thanks much for the help and all the replies.