Proper screw size for Model M Screw Mod

apastuszak

23 May 2018, 14:40

I'm looking to buy some screws for a Model M screw mod.

I followed this guide here: workshop-f7/ibm-model-m-screw-nut-and-b ... crew%20mod

The picture in the guide shows the following screws: 7982 A2 2,2x6,5

That seems to a screw size only available from German eBay sellers. I would prefer not to pay shipping from Germany. Is there an equivalent size I can use that is readily available in the US?

unoquepasa

23 May 2018, 17:30

Hope this post from geekhack helps you. It's about bolt-modding instead of screw-modding, but is written by an american so I figure you can get the parts you need from the same source:

https://geekhack.org/index.php?topic=62226.0

Edit: the part about the "ball end" bit for making the divot to stabilize the drill bit is an extremely useful advice.

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j0d1

23 May 2018, 17:50


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fohat
Elder Messenger

23 May 2018, 18:41

"A2" is another name for M2 (= metric 2mm diameter for screws, nuts, and washers).

8mm long screws are the easiest to work with, but they are too long for the bottom-most row and will interfere with the case closing.

apastuszak

23 May 2018, 19:46

fohat wrote: "A2" is another name for M2 (= metric 2mm diameter for screws, nuts, and washers).

8mm long screws are the easiest to work with, but they are too long for the bottom-most row and will interfere with the case closing.
So, what size for the bottom row? 6 mm?

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Iggy

23 May 2018, 19:48

apastuszak wrote: So, what size for the bottom row? 6 mm?
I think I used 6mm when I did a screw-mod on my M122. I left out the washers, they took up too much space.

apastuszak

23 May 2018, 19:58

Just ordered 100 6 mm and 100 8 mm screws from some eBay seller in China. If I can get this M122 terminal model someone is selling near my house for $25.00, I'll experiment.

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depletedvespene

23 May 2018, 20:04

Good luck!

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green-squid

23 May 2018, 20:29

Good luck with the repair! Image

(BTW, wanted to try this old-school emoticon .gif I found that was intended to be used on MSN :) )

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Coco

11 Jun 2019, 05:03

Iggy wrote:
23 May 2018, 19:48
apastuszak wrote: So, what size for the bottom row? 6 mm?
I think I used 6mm when I did a screw-mod on my M122. I left out the washers, they took up too much space.
Will this be the same concept for a Model M (1391401)?

daijoubu

11 Jun 2019, 07:38

I've just completed my Model M screw mod.

I've used M2 x 8mm truss head screws with sharp points, which protruded a little from the top of the barrel frame. I drilled 2 out of 3 of the right most points, at the numpad under where vertical 2u '+' and 'Enter' wire stabilized keys are to be, and the protrusion will interfere with the movement of the stabilizer. I just fixed that by grinding the sharp points down by half mm and it solved the issue.

To avoid the above, a M2 x 7mm would be ideal

I also used a 1.6mm drill bit to make the pilot holes

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Coco

11 Jun 2019, 07:55

daijoubu wrote:
11 Jun 2019, 07:38
I've just completed my Model M screw mod.

I've used M2 x 8mm truss head screws with sharp points, which protruded a little from the top of the barrel frame. I drilled 2 out of 3 of the right most points, at the numpad under where vertical 2u '+' and 'Enter' wire stabilized keys are to be, and the protrusion will interfere with the movement of the stabilizer. I just fixed that by grinding the sharp points down by half mm and it solved the issue.

To avoid the above, a M2 x 7mm would be ideal

I also used a 1.6mm drill bit to make the pilot holes
Good job on the mod! Glad to see that the problem was resolved. Since my Model M is of the year '89 that doesn't have the stabilizers aside from the space bar, I'm assuming M2 X 8 mm will be okay?

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Howard81

11 Jun 2019, 14:27

I use stainless M2 x 6mm POZI countersunk machine screws.

daijoubu

12 Jun 2019, 17:13

Coco wrote:
11 Jun 2019, 07:55
daijoubu wrote:
11 Jun 2019, 07:38
I've just completed my Model M screw mod.

I've used M2 x 8mm truss head screws with sharp points, which protruded a little from the top of the barrel frame. I drilled 2 out of 3 of the right most points, at the numpad under where vertical 2u '+' and 'Enter' wire stabilized keys are to be, and the protrusion will interfere with the movement of the stabilizer. I just fixed that by grinding the sharp points down by half mm and it solved the issue.

To avoid the above, a M2 x 7mm would be ideal

I also used a 1.6mm drill bit to make the pilot holes
Good job on the mod! Glad to see that the problem was resolved. Since my Model M is of the year '89 that doesn't have the stabilizers aside from the space bar, I'm assuming M2 X 8 mm will be okay?
Yup in that case 8mm will be fine. It should be easily sourced.
Truss head shaped is good, and when you drill try to keep the drill as perpendicular as possible to the barrel frame

Fkazim

13 Jun 2019, 10:10

I used M2 6mm machine screws with countersunk heads and that worked great for me with no problems at all

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