J
John Larkin
Guest
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
I guess I\'ll have to try it.
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L
Lasse Langwadt Christensen
Guest
mandag den 19. juni 2023 kl. 17.50.16 UTC+2 skrev John Larkin:
how low do you need? https://www.mcmaster.com/products/low-profile-head-socket-cap-screws/alloy-steel-ultra-low-profile-socket-head-screws/
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
how low do you need? https://www.mcmaster.com/products/low-profile-head-socket-cap-screws/alloy-steel-ultra-low-profile-socket-head-screws/
F
Fred Bloggs
Guest
On Monday, June 19, 2023 at 11:50:16â¯AM UTC-4, John Larkin wrote:
Countersink it for a flat head. Head should end up flush with the package, can\'t beat that:
https://www.homedepot.com/b/Hardware-Fasteners-Screws-Machine-Screws/Flat-Head/N-5yc1vZc27iZ1z18t94
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Countersink it for a flat head. Head should end up flush with the package, can\'t beat that:
https://www.homedepot.com/b/Hardware-Fasteners-Screws-Machine-Screws/Flat-Head/N-5yc1vZc27iZ1z18t94
J
John Larkin
Guest
On Mon, 19 Jun 2023 08:57:14 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
The heights are good, the prices aren\'t!
A regular screw and a lockwasher cost me over 0.1\", and I need less.
With locktite, I can eliminate the lockwasher.
A really thin custom AlN insulator will help a bit. Isolated TO-247s
are expensive and hard to get.
I could just epoxy the fets down, but that has downsides.
<langwadt@fonz.dk> wrote:
mandag den 19. juni 2023 kl. 17.50.16 UTC+2 skrev John Larkin:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
how low do you need? https://www.mcmaster.com/products/low-profile-head-socket-cap-screws/alloy-steel-ultra-low-profile-socket-head-screws/
The heights are good, the prices aren\'t!
A regular screw and a lockwasher cost me over 0.1\", and I need less.
With locktite, I can eliminate the lockwasher.
A really thin custom AlN insulator will help a bit. Isolated TO-247s
are expensive and hard to get.
I could just epoxy the fets down, but that has downsides.
J
John Larkin
Guest
On Mon, 19 Jun 2023 08:57:14 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
You are really good at parts research. Please email me.
<langwadt@fonz.dk> wrote:
mandag den 19. juni 2023 kl. 17.50.16 UTC+2 skrev John Larkin:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
how low do you need? https://www.mcmaster.com/products/low-profile-head-socket-cap-screws/alloy-steel-ultra-low-profile-socket-head-screws/
You are really good at parts research. Please email me.
L
Lasse Langwadt Christensen
Guest
mandag den 19. juni 2023 kl. 18.13.01 UTC+2 skrev John Larkin:
yeh, but now you konw they exist and they can surely be found much cheaper, I guess you want something like #4-40, but M3 seems to be more common
https://www.ebay.co.uk/itm/284167006281
https://ogsecure.co.uk/products/m3-ultra-thin-wafer-flat-head-low-profile-screws-bolt-allen-key-stainless-steel?variant=40403358318653
On Mon, 19 Jun 2023 08:57:14 -0700 (PDT), Lasse Langwadt Christensen
lang...@fonz.dk> wrote:
mandag den 19. juni 2023 kl. 17.50.16 UTC+2 skrev John Larkin:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
how low do you need? https://www.mcmaster.com/products/low-profile-head-socket-cap-screws/alloy-steel-ultra-low-profile-socket-head-screws/
The heights are good, the prices aren\'t!
yeh, but now you konw they exist and they can surely be found much cheaper, I guess you want something like #4-40, but M3 seems to be more common
https://www.ebay.co.uk/itm/284167006281
https://ogsecure.co.uk/products/m3-ultra-thin-wafer-flat-head-low-profile-screws-bolt-allen-key-stainless-steel?variant=40403358318653
L
Lasse Langwadt Christensen
Guest
mandag den 19. juni 2023 kl. 18.13.01 UTC+2 skrev John Larkin:
maybe something like this? https://www.digikey.dk/da/products/detail/aavid-thermal-division-of-boyd-corporation/MAX08NG/1625322
On Mon, 19 Jun 2023 08:57:14 -0700 (PDT), Lasse Langwadt Christensen
lang...@fonz.dk> wrote:
mandag den 19. juni 2023 kl. 17.50.16 UTC+2 skrev John Larkin:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
how low do you need? https://www.mcmaster.com/products/low-profile-head-socket-cap-screws/alloy-steel-ultra-low-profile-socket-head-screws/
The heights are good, the prices aren\'t!
A regular screw and a lockwasher cost me over 0.1\", and I need less.
With locktite, I can eliminate the lockwasher.
A really thin custom AlN insulator will help a bit. Isolated TO-247s
are expensive and hard to get.
I could just epoxy the fets down, but that has downsides.
maybe something like this? https://www.digikey.dk/da/products/detail/aavid-thermal-division-of-boyd-corporation/MAX08NG/1625322
J
John Larkin
Guest
On Mon, 19 Jun 2023 10:32:14 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
I\'ve done that
https://www.dropbox.com/s/nmyb9pz0qpma2xa/Amp.jpg?dl=0
but it adds more height. I\'ll have boards in a card cage on 1.6\"
centers, and I\'m stacking a CPU cooler/fan thing with giant mosfets.
The screw heads could hit adjacent boards.
I could go to TO220s, which need less screw height.
<langwadt@fonz.dk> wrote:
mandag den 19. juni 2023 kl. 18.13.01 UTC+2 skrev John Larkin:
On Mon, 19 Jun 2023 08:57:14 -0700 (PDT), Lasse Langwadt Christensen
lang...@fonz.dk> wrote:
mandag den 19. juni 2023 kl. 17.50.16 UTC+2 skrev John Larkin:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
how low do you need? https://www.mcmaster.com/products/low-profile-head-socket-cap-screws/alloy-steel-ultra-low-profile-socket-head-screws/
The heights are good, the prices aren\'t!
A regular screw and a lockwasher cost me over 0.1\", and I need less.
With locktite, I can eliminate the lockwasher.
A really thin custom AlN insulator will help a bit. Isolated TO-247s
are expensive and hard to get.
I could just epoxy the fets down, but that has downsides.
maybe something like this? https://www.digikey.dk/da/products/detail/aavid-thermal-division-of-boyd-corporation/MAX08NG/1625322
I\'ve done that
https://www.dropbox.com/s/nmyb9pz0qpma2xa/Amp.jpg?dl=0
but it adds more height. I\'ll have boards in a card cage on 1.6\"
centers, and I\'m stacking a CPU cooler/fan thing with giant mosfets.
The screw heads could hit adjacent boards.
I could go to TO220s, which need less screw height.
P
Phil Hobbs
Guest
On 2023-06-19 11:49, John Larkin wrote:
Be careful about overtorqueing it, because stretching the metal might
conceivably cause the die to crack or delaminate.
I\'d definitely want to torture-test for that possibility.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Be careful about overtorqueing it, because stretching the metal might
conceivably cause the die to crack or delaminate.
I\'d definitely want to torture-test for that possibility.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
J
John Larkin
Guest
On Mon, 19 Jun 2023 09:04:46 -0700 (PDT), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:
That\'s the idea, as long as it doesn\'t destroy the silicon.
We\'d need carbide countersinks. That mosfet epoxy is hell on tools.
<bloggs.fredbloggs.fred@gmail.com> wrote:
On Monday, June 19, 2023 at 11:50:16?AM UTC-4, John Larkin wrote:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Countersink it for a flat head. Head should end up flush with the package, can\'t beat that:
https://www.homedepot.com/b/Hardware-Fasteners-Screws-Machine-Screws/Flat-Head/N-5yc1vZc27iZ1z18t94
That\'s the idea, as long as it doesn\'t destroy the silicon.
We\'d need carbide countersinks. That mosfet epoxy is hell on tools.
L
Lasse Langwadt Christensen
Guest
mandag den 19. juni 2023 kl. 20.11.58 UTC+2 skrev John Larkin:
might be better with a counter bore instead of a counter sink
On Mon, 19 Jun 2023 09:04:46 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:
On Monday, June 19, 2023 at 11:50:16?AM UTC-4, John Larkin wrote:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Countersink it for a flat head. Head should end up flush with the package, can\'t beat that:
https://www.homedepot.com/b/Hardware-Fasteners-Screws-Machine-Screws/Flat-Head/N-5yc1vZc27iZ1z18t94
That\'s the idea, as long as it doesn\'t destroy the silicon.
We\'d need carbide countersinks. That mosfet epoxy is hell on tools.
might be better with a counter bore instead of a counter sink
J
John Larkin
Guest
On Mon, 19 Jun 2023 11:27:39 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
Yes, we could drop in a lockwasher.
<langwadt@fonz.dk> wrote:
mandag den 19. juni 2023 kl. 20.11.58 UTC+2 skrev John Larkin:
On Mon, 19 Jun 2023 09:04:46 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:
On Monday, June 19, 2023 at 11:50:16?AM UTC-4, John Larkin wrote:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Countersink it for a flat head. Head should end up flush with the package, can\'t beat that:
https://www.homedepot.com/b/Hardware-Fasteners-Screws-Machine-Screws/Flat-Head/N-5yc1vZc27iZ1z18t94
That\'s the idea, as long as it doesn\'t destroy the silicon.
We\'d need carbide countersinks. That mosfet epoxy is hell on tools.
might be better with a counter bore instead of a counter sink
Yes, we could drop in a lockwasher.
J
John Larkin
Guest
On Mon, 19 Jun 2023 08:49:52 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:
I\'m working from home today and I have a hand drill and a very rusty
old countersink, a family heirloom.
https://www.dropbox.com/scl/fi/y5s1bsc2omn341rnxkicq/TO247_countersunk_4-40.jpg?dl=0&rlkey=cqenr4ev8iic5zgujqor8cns1
This looks OK. The 4-40 screw should apply plenty of force and it
centers the fet nicely. It would need locktite so thermal cycling
doesn\'t loosen it up.
<jlarkin@highlandSNIPMEtechnology.com> wrote:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
I\'m working from home today and I have a hand drill and a very rusty
old countersink, a family heirloom.
https://www.dropbox.com/scl/fi/y5s1bsc2omn341rnxkicq/TO247_countersunk_4-40.jpg?dl=0&rlkey=cqenr4ev8iic5zgujqor8cns1
This looks OK. The 4-40 screw should apply plenty of force and it
centers the fet nicely. It would need locktite so thermal cycling
doesn\'t loosen it up.
J
Joe Gwinn
Guest
On Mon, 19 Jun 2023 09:12:39 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:
Stainless steel flat head hex socket screws with a 100-degree cone
total angle are common, originally developed for use in airplanes.
..<https://www.mcmaster.com/90729A166/>
Suitable 100-degree carbide countersinks are also available.
Joe Gwinn
<jlarkin@highlandSNIPMEtechnology.com> wrote:
On Mon, 19 Jun 2023 08:57:14 -0700 (PDT), Lasse Langwadt Christensen
langwadt@fonz.dk> wrote:
mandag den 19. juni 2023 kl. 17.50.16 UTC+2 skrev John Larkin:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
how low do you need? https://www.mcmaster.com/products/low-profile-head-socket-cap-screws/alloy-steel-ultra-low-profile-socket-head-screws/
The heights are good, the prices aren\'t!
A regular screw and a lockwasher cost me over 0.1\", and I need less.
With locktite, I can eliminate the lockwasher.
A really thin custom AlN insulator will help a bit. Isolated TO-247s
are expensive and hard to get.
I could just epoxy the fets down, but that has downsides.
Stainless steel flat head hex socket screws with a 100-degree cone
total angle are common, originally developed for use in airplanes.
..<https://www.mcmaster.com/90729A166/>
Suitable 100-degree carbide countersinks are also available.
Joe Gwinn
C
Chris
Guest
On Tuesday, 20 June 2023 at 01:50:16 UTC+10, John Larkin wrote:
Rivets?
--
Cheers,
Chris.
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Rivets?
--
Cheers,
Chris.
W
wmartin
Guest
On 6/19/23 18:57, Chris wrote:
nose of the rivet setting tool may want to mash something else nearby...
A copper rivet could work, but there are issues with installing: theOn Tuesday, 20 June 2023 at 01:50:16 UTC+10, John Larkin wrote:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Rivets?
--
Cheers,
Chris.
nose of the rivet setting tool may want to mash something else nearby...
W
whit3rd
Guest
On Monday, June 19, 2023 at 8:50:16â¯AM UTC-7, John Larkin wrote:
The hole is 3.5mm, so an M3 flat head cap screw with a countersinked washer would
hold it down; here are 1.8mm thick offerings for M3 screws. Is 1.8mm too high?
<https://www.mcmaster.com/products/countersunk-washers/>
I\'m not seeing any measure of the recess dimensions around the clear hole, though.
The screw would be capable of touching the tab, which might not work for you.
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
The hole is 3.5mm, so an M3 flat head cap screw with a countersinked washer would
hold it down; here are 1.8mm thick offerings for M3 screws. Is 1.8mm too high?
<https://www.mcmaster.com/products/countersunk-washers/>
I\'m not seeing any measure of the recess dimensions around the clear hole, though.
The screw would be capable of touching the tab, which might not work for you.
J
Jasen Betts
Guest
On 2023-06-19, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
> Has anyone done this? I need to get the mounting screw height down.
Sounds risky, the wedge shape of the screw head will be working
against the glass-filled resin of the body. I don\'t think that stuff
is very strong in tension.
--
Jasen.
ðºð¦ Слава УкÑаÑнÑ
> Has anyone done this? I need to get the mounting screw height down.
Sounds risky, the wedge shape of the screw head will be working
against the glass-filled resin of the body. I don\'t think that stuff
is very strong in tension.
I guess I\'ll have to try it.
--
Jasen.
ðºð¦ Слава УкÑаÑнÑ
J
Jasen Betts
Guest
On 2023-06-20, Chris <chris.863@live.com> wrote:
blind rivets tend to cause mechanical shock when the stem snaps
leading to early failures. Swage rivets - maybe that could work
if you can find a way to set them without damaging the MOSFET.
--
Jasen.
ðºð¦ Слава УкÑаÑнÑ
On Tuesday, 20 June 2023 at 01:50:16 UTC+10, John Larkin wrote:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Rivets?
blind rivets tend to cause mechanical shock when the stem snaps
leading to early failures. Swage rivets - maybe that could work
if you can find a way to set them without damaging the MOSFET.
--
Jasen.
ðºð¦ Слава УкÑаÑнÑ
J
John Larkin
Guest
On Mon, 19 Jun 2023 18:57:31 -0700 (PDT), Chris <chris.863@live.com>
wrote:
Rework would be difficult, and a rivet adds height too.
The reason to not just epoxy the fets down would be the rework issue.
And the mess, although there are some instant-set thermally conductive
super-glue things.
wrote:
On Tuesday, 20 June 2023 at 01:50:16 UTC+10, John Larkin wrote:
Has anyone done this? I need to get the mounting screw height down.
I guess I\'ll have to try it.
Rivets?
Rework would be difficult, and a rivet adds height too.
The reason to not just epoxy the fets down would be the rework issue.
And the mess, although there are some instant-set thermally conductive
super-glue things.