Q8 modding

Tom_E · 2017-09-19T13:58:29.000Z

Dang, sorry - forgot bout that measurement. I tried finding that Ali store in the English global site of Ali but had no luck.

I've been researching "laptop" screw sets and all that I found have a mild bevel under the tops - wasn't sure if these would work ok.

That Ali listing doesn't show the screws in detail so can't tell. I'd expect though them to have the bevel.

TheOnlyDocc · 2017-09-19T14:11:00.000Z

I contacted the seller and asked about the exact measurements. Of the M3x6 and the M3x8 srews and this is his answere:

M3x6: D=5mm, L=6mm, T=0.5mm

M3x8: D=5mm, L=8mm, T=0.5mm

T is the head thicknes. And even if it is 0,7 or 0,8mm the brass ring is 1,5mm if i remember correct so enough clearence.

Etex · 2017-09-19T14:16:27.000Z

Silicon switch cover measures 10.25mm diameter for the button.

TheOnlyDocc · 2017-09-19T14:19:50.000Z

So this should fit?
http://www.kaidomain.com/p/S024951.10mm(D)x8mm(H)-Glow-in-the-dark-Silicone-Tailcaps-Transparent
http://www.kaidomain.com/p/S024949.10mm(D)x8mm(H)-Glow-in-the-dark-Silicone-Tailcaps-Green

Tom_Tom · 2017-09-19T14:41:40.000Z

Tom E:

I agree to disagree there. Flathead screws are simply the wrong screw to use for this kind of mount. The only reason this is an issue now in production is that ThorFire went from a M2.5 to a M3, and the M3 panhead had a higher head, so, in their infinite wisdom they went with a beveled flathead that requires perfect tolerances, and if they are not perfect, what happens? The screw damages the aluminum threadings in the body, also the screw doesn’t sit down all the way, puts stress on the board and screw top. Under a good shock or series of shocks, what happens with components under stress? Things can break or crack.

We are in total agreement, the M3 flathead/countersunk screws used in production are absolutely wrong, for several reasons.

Likewise the holes in the PCB are wrong, I suspect they may have been drilled for M2.5 clearance. Whatever the reason, the screw threads should not bite into them. Apart from just being wrong, you cannot be sure of clamping the PCB against the head if both are threaded. They should be re-drilled to 3mm minimum .

I am simply expressing caution in advising the best way forward at this moment, because for the less experienced it would be better to leave them be for now, until a consensus is reached as to the best replacement, ideally to be supplied as a retrofit kit, for those who want them.

Given the risk of chewing up the heads trying to remove them (cheap screwdrivers, lack of experience in their use, etc, and generally ending up in a muddle …

Tom_Tom · 2017-09-19T15:21:19.000Z

TheOnlyDocc:

I contacted the seller and asked about the exact measurements. Of the M3x6 and the M3x8 srews and this is his answere:

M3x6: D=5mm, L=6mm, T=0.5mm

M3x8: D=5mm, L=8mm, T=0.5mm

T is the head thicknes. And even if it is 0,7 or 0,8mm the brass ring is 1,5mm if i remember correct so enough clearence.

Good find !

But be cautious, these type of screw often use a “JIS” cross-head, which is not at-all compatible with any usual Phillips or Pozidriv screwdriver. Really badly incompatible (chews and strips), as anyone who fettles laptops, cameras etc. will know.

JIS screwdrivers are difficult and expensive to source in my experience (paid a lot for mine, from Microtools).

en.wikipedia.org

List of screw drives

At a minimum, a screw drive is a set of shaped cavities and protrusions on the screw head that allows torque to be applied to it. Usually, it also involves a mating tool, such as a screwdriver, that is used to turn it. The following heads are categorized based on frequency,[citation needed] with some of the less-common drives being classified as "tamper-resistant". Most heads come in a range of sizes, typically distinguished by a number, such as "Phillips #00". These sizes do not necessarily d...

MtnDon · 2017-09-19T14:35:35.000Z

Tom E:

Dang, sorry - forgot bout that measurement. I tried finding that Ali store in the English global site of Ali but had no luck.

I’ve been researching “laptop” screw sets and all that I found have a mild bevel under the tops - wasn’t sure if these would work ok.

That Ali listing doesn’t show the screws in detail so can’t tell. I’d expect though them to have the bevel.

??? M3x5mm Nickel Wafer Head Machine Screw #20924 [20924] : Metric Screws!, We have the screws you need!

Tom_E · 2017-09-19T14:39:43.000Z

All good!

Wow, MtnDon, those are look'n good, but pricey. $25 for qty 100, but single piece price ain't bad to buy a little more than needed.

Yea, BoltDepot.com has a very limited metric collection, much more for US sizes.

Etex · 2017-09-19T14:45:34.000Z

TheOnlyDocc:

So this should fit?
http://www.kaidomain.com/p/S024951.10mm(D)x8mm(H)-Glow-in-the-dark-Silicone-Tailcaps-Transparent
http://www.kaidomain.com/p/S024949.10mm(D)x8mm(H)-Glow-in-the-dark-Silicone-Tailcaps-Green

joechina · 2017-09-19T15:46:09.000Z

Tom Tom:

TheOnlyDocc:

I contacted the seller and asked about the exact measurements. Of the M3x6 and the M3x8 srews and this is his answere:

M3x6: D=5mm, L=6mm, T=0.5mm

M3x8: D=5mm, L=8mm, T=0.5mm

T is the head thicknes. And even if it is 0,7 or 0,8mm the brass ring is 1,5mm if i remember correct so enough clearence.

Good find !

But be cautious, these type of screw often use a “JIS” cross-head, which is not at-all compatible with any usual Phillips or Pozidriv screwdriver. Really badly incompatible (chews and strips), as anyone who fettles laptops, cameras etc. will know.

JIS screwdrivers are difficult and expensive to source in my experience (paid a lot for mine, from Microtools).

List of screw drives - Wikipedia

The pic in the review show a screwdriver included, like in the product pic. So it should be OK

Tom_Tom · 2017-09-19T16:20:44.000Z

Tom E:

All good!

Wow, MtnDon, those are look’n good, but pricey. $25 for qty 100, but single piece price ain’t bad to buy a little more than needed.

Decent screws do cost money.

Amazing that you can get a Chinese kit of 300 for $7.60, but generally, you get what you pay for …

That said, this application is non-critical, really they are only there for location purposes. No need to crank them down, just nip them up gently, and in my case then put a dab of weak red locking compound between the head and the PCB.

Another tip: rub the threads on a block of beeswax first before inserting. This lubricates the threads, prevents wear and galling with repeated removal/re-insertion, and also stiffens the screw against loosening.

Mostly the cheapest screws (and threading in the head) are only expected to be assembled once, and never dis-assembled again, for which application they are adequate.

Tom_Tom · 2017-09-19T15:58:53.000Z

[quote=joechina]

[quote=Tom Tom]

TheOnlyDocc:

The pic in the review show a screwdriver included, like in the product pic. So it should be OK

Excellent.

I’ll be ordering a set myself anyway, for other applications.

ImA4Wheelr · 2017-09-19T16:00:02.000Z

I'm sure someone has answered this, but I couldn't find anything in my scanning of this thread. Is there any problem with boring the driver mounting holes enough to clear the threads and then adding a counter sink for the screw head to fit flat?

I haven't look at the driver pics to determine if the screw holes are the only thru-holes for Batt- connection, but that seems unlikely.

steel_1024 · 2017-09-19T16:00:26.000Z

ImA4Wheelr · 2017-09-19T16:06:56.000Z

^

Yep, that is what I'm talking about. Does that cause any problems? It all looks good from here. Plenty of thru-holes and no shorted or broken traces appear evident.

steel_1024 · 2017-09-19T16:18:05.000Z

All fine

Indicator resistor change to 22K. It’s too bright for me still. :person_facepalming:

ImA4Wheelr · 2017-09-19T16:31:40.000Z

^

Great. I should get mine today and would like to do that to make sure the driver is nicely seated. Thank you steel_1024 :)

Tom_Tom · 2017-09-19T16:45:44.000Z

ImA4Wheelr:

I’m sure someone has answered this, but I couldn’t find anything in my scanning of this thread. Is there any problem with boring the driver mounting holes enough to clear the threads and then adding a counter sink for the screw head to fit flat?

I haven’t look at the driver pics to determine if the screw holes are the only thru-holes for Batt- connection, but that seems unlikely.

Unless I have missed something, the Batt- connection is entirely through contact between the end of the battery tube and the outer ring on the driver PCB (and all of those vias in it). The need for any contact through the screws or the reverse of the driver and the head is I think a red-herring.

So a DIY fix to countersink the PCB (and maybe a little way into the metal of the head) is a great zero-cost way to improve the mechanical integrity.

But this would not be practical for Thorfire in production. Putting a countersink into the driver PCB as a production step is just not practical.

I am hoping that we can steer Thorfire to do the right thing in future production by using a correct thin pan-head screw, in a correct sized PCB hole.

Lexel · 2017-09-19T17:01:49.000Z

Good that I have 90 degree countersink drillbits
They are cheap

Like this in different sizes
https://de.aliexpress.com/item/High-Quality-3-Flute-90-Degree-HSS-Countersink-Drill-Bit-Wood-Steel-Chamfer-Cutter-Tool-6/32767774041.html

hank · 2017-09-19T17:07:26.000Z

the cheapest screws (and threading in the head) are only expected to be assembled once, and never dis-assembled again

Which is to say — that’s not the BLF way.

LEDs and drivers keep getting better, and we keep using the new stuff in the old bodies.