deskthority

I've owned and refurbished a fair few Model Ms in my time, until now I was fortunate enough that they had enough of the rivets in place not to require bolt or screw modding. Unfortunately my most recent acquisition is missing a lot of rivets though (I counted 24 and some more are loose)

I've done a fair bit of research into bolt/screw modding and decided that the best route to take would be to screw mod it. The only problem is I can't find any information on what size screws to use, or what guide hole to

The closest I have come is a geekhack thread from a few years ago that recommends 2-56 x 5/16 screws and a 0.070" diameter pilot hole.

Does any else have any recommendations for what to use or a rough conversion for the drill bit and screws above in metric?

I googled and the first Deskthority post was this one: workshop-f7/ibm-model-m-screw-nut-and-b ... t9169.html

There is also a Geekhack wiki page: http://wiki.geekhack.org/index.php?titl ... d_Bolt_Mod

Both guides have their parts in metric.

FYI you posted this thread twice.

M2 machine screws

I use 8mm long one along with nuts and washers, any longer and you will hit the case on the lower (space bar) side. On the upper half of the curve you can use 9mm or 10mm long and have an easier time installing the washers and nuts, but that would require ordering 2 different lengths.

For doing a "screw" mod without nuts something like an M2 x 5mm would probably be adequate but I have always just used my 8mm for repair work and they work fine.

I use a 1/16" drill bit which is slightly larger than 1.5mm, and it works perfectly. The screw is slightly larger than the hole and its threads cut their way in through the plastic and hold tight. With a 1.5mm bit it may be tighter and better but harder to install. One thing that you can do is to take a small Phillips head screwdriver and give a small twist at the mouth of the hole to ream out the opening very slightly to allow the first thread to gain purchase.

fohat wrote: For doing a "screw" mod without nuts something like an M2 x 5mm would probably be adequate but I have always just used my 8mm for repair work and they work fine.

I use a 1/16" drill bit which is slightly larger than 1.5mm, and it works perfectly. The screw is slightly larger than the hole and its threads cut their way in through the plastic and hold tight. With a 1.5mm bit it may be tighter and better but harder to install. One thing that you can do is to take a small Phillips head screwdriver and give a small twist at the mouth of the hole to ream out the opening very slightly to allow the first thread to gain purchase.

This is what I've been doing. Except I got a little too rambunctious with the Dremel and now have these tiny pinholes on the visible side of the barrel plate. I'll press some filler into each of the holes, paint again, and hope that the screws don't push the filler back out.

Thanks a lot guys, really fantastic answers. I take it in terms of head, just the smaller/lower profile the better?

I'll let you know how I get on

If the screws are coming up from the bottom, you should have sufficient clearance. Unfortunately, M2 heads are often small enough (in diameter) that they can slide sideways through the original oval-shaped holes, so I recommend pan-head screws and washers.

I have no comparison between screw vs. bolt mod, as I am only experienced with screw-modding.

In terms of the correct screws, here's what I've been using, with success.
These were a recommendation from idollar, who knows what he's doing.

http://www.schrauben-lexikon.de/norm/DIN_7982.asp

DIN 7982 2,2x6,5 mm stainless steel

PS: It was this exact item and seller, disregard the example picture