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Discussion Starter · #1 ·
I have picked up a large number of NOS Model Motoring bodies. Although the screw posts have holes, they are not threaded. One body did have a screw in it, but when I compare it to the screws supplied with Dash bodies, they are not the same, nor will the Dash screw go into the already threaded post.

I've always noticed some screws have a point at the end, while others are flat.

I looked in other threads to see if I could find an answer as to what size screw is needed and it looks like a 2-56 x 1/4" would be right. I found the following at McMaster-Carr - would this be the right screw to use?

http://www.mcmaster.com/#thread-cutting-screws/=j4acjl

Thanks...Joe
 

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I have ordered screws from McMaster-Carr a couple times. I was able to find ones that look (to me, anyway) exactly like original Tjet body screws. This is directly off the packing slip from the last time I ordered:

90057A077 Zinc-plated Steel Pan Head Slotted Thread-Form Screw, No.2 X 1/4" Length, Packs of 100. $6.08

I actually kept the slip around for reference for the next time someone asked, as this comes up from time to time.

Very happy with the screws, but the shipping charges stunk. For that box of screws and a package of O-rings, I paid $8.25 shipping. When these run out, I plan to bring the specs to Fastenal, which recently opened near me, and see if they have the equivalent...

--rick

edit: hmmm. i am putzing around with the McM-C site to find the stock number I gave... they seem to have it in stock, but they don't offer an illustration. also, the site likes IE better than it likes Firefox, but it's apparently not crazy about either...

edit again: interesting. the Fastenal site shows that they have these in quantities of 10,000. now if only i could find that tractor trailer load of 5000 NOS chassis, i'd be set. :lol: but seriously, the local Fastenal has been very good about breaking packages to sell me a few of something, so I assume you can get them in smaller quantities than that. i just went there last week to buy an odd size pop rivet and they broke open a bag of 100 to sell me 10 of them...
 

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Discussion Starter · #3 · (Edited)
Hi Rick,
The screws I saw were 90087A102, but if you found the perfect match, I'll go with your stock number. And you are correct - the website will not show an illustration. It's a lot easier to know what you are getting with a picture.

I have a Grainger just down the road, so if I have the specs I can see if they carry these exact sized screws and save on the shipping.

I also see part number 67568725 on www.mscdirect.com. I just don't know if they are thread cutting.

Do your screws specify the number of threads per inch, or only the diameter (#2)? Are they Phillips head or slotted? Did they cut the threads fairly easily?

Thanks...Joe
 

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Here, I got a thousand words for you:



On the left is one I got from McM-C, on the right is one from an ancient Pit Kit.

To answer your questions:

When I have looked for these, I have NOT found threads per inch in the listings. The ones I got are slotted like the original Tjet ones. And to be honest, when I have used them in MM bodies, they take a little work to get in. I never felt like they were going to split the post or anything, but they don't just twist in effortlessly either.

Now that I think of it, there IS a screw that I think cuts into those posts a little easier. If you open up an early Playing Mantis Thunderjet pullback, they came with Phillips-head screws that had a slightly different thread and a V cut into the point that was supposed to help cut threads. I like them, but I'd have no idea how to find them from a supplier like McM or whoever...

FWIW, this is how I found what I think is the equivalent screw at Fastenal:

Screws>Thread cutting screws>Diameter #2>Length 1/4">Head: Pan>Drive: Slotted>only one choice. and the illustrated thread is much longer than 1/4", but I think it's just a representative pic...

--rick
 

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When I have looked for these, I have NOT found threads per inch in the listings. The ones I got are slotted like the original Tjet ones.
I don't know that you would because it's not a machine screw, it's a screw meant for going into an unthreaded hole, at least the 1st time :eek: interesting thread, I've often wanted to hunt some down that were maybe a little longer or shorter, seems like it should be easy to just say it's "Screw No.X" but apparently not
 

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Discussion Starter · #7 · (Edited)
To answer your questions:

When I have looked for these, I have NOT found threads per inch in the listings. The ones I got are slotted like the original Tjet ones. And to be honest, when I have used them in MM bodies, they take a little work to get in. I never felt like they were going to split the post or anything, but they don't just twist in effortlessly either.
Rick,

From the picture, it looks like there are about 6-7 threads on that screw which would make it 24-28 threads per inch. I bought some screws years ago off ebay (I believe) and they also look to have the same 6-7 threads per 1/4 inch.

Now that I think of it, there IS a screw that I think cuts into those posts a little easier. If you open up an early Playing Mantis Thunderjet pullback, they came with Phillips-head screws that had a slightly different thread and a V cut into the point that was supposed to help cut threads. I like them, but I'd have no idea how to find them from a supplier like McM or whoever...
The pullback screws would only be good if they have the same thread as the screw you plan to use. Otherwise, you could make a mess inside the post by cross-threading.

I went ahead and ordered a couple bags of those screws from McMaster-Carr. Based on the picture you posted, that's about as close to original as you can get. As I mentioned above, I have bodies from Dash which came with screws and those screws have a pointed end. So there are no doubt different screws that will work.

Thanks...Joe
 

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Discussion Starter · #8 · (Edited)
Rick,
Received the screws and they work just great. They certainly look identical to existing body screws.

I tried them in an old Aurora body and they went right in. I then tried them in a NOS Model Motoring body and as you pointed out, they are very tight the first time as they are cutting threads. Once the threads are cut, they are a perfect fit.

It takes a minute or two to work the screw into the MM body post and you can only turn it about 1/8 turn at a time. Any faster than that and it feels as if you could crack the post. If the hole were tapped first, that would be even better.

So bottom line is they are great for original Aurora and NOS MM bodies. I'll need to see how they work on a Dash body and I have a few more MM bodies also.

Thanks...Joe
 

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someone pointed out on one of the threads that a certain brand of slot cars had screws that were self threading in plastic such as a mounting post.

to replicate that, you use a cut off wheel in a moto-tool (Dermel is one brand that comes to mind) to score a similar cut into the beginning of the threads on the screw.

why, I've even heard of folks that have soldered or JB welded one onto an extra screw driver to use as a threading tool for all their future projects threading mounting posts in new bodies or untapped resin bodies or plastic tubing to use for mounting posts for slot car bodies.
 

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A ways back there was a guy (zachbuff I believe) selling an inexpensive post tapping tool on the bay. I think it was a self tapping screw encased in a resin handle. He got 3-4.00 a pop for them, and they were quite handy to have on the bench. Mine has held up well, though it's about 1/8" wider now with paint build up. It used to be my body holder when painting until I got the poster putty.
 

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Discussion Starter · #14 ·
Yesterday I tried to install screws for the first time into a Dash body. The bodies came with screws, but when I tried them, they were so tight that I backed off because I did not want to split the post. I then tried some of the above mentioned screws and they were tight as well. Again I backed off.

I then tried to install a one of these screws into a Nu-Rora body and felt the same way - just too tight and I did not want to risk splitting the post.

So I figure the safe way to do this is to find a tap to first open the hole enough so the screw threads easily. As mentioned earlier in this thread, the McMaster-Carr site does not list a screw size for these, only that they are size 2 (the box they come in also does not specify the size - or part number). It also does not list these in the catalog.

If you search the site based on part number, you will get a hit. You can then click on "catalog page" (which supposedly would show you the page where this part is listed). This part number does not show up in the catalog, but there is a notation that the phillips head screws in the catalog can also be purchased with a slotted head. I am thinking that 90057A077 is the same as 90056A077 (Phillips head), just with a slotted head. If so, the thread size is 2-32.

So I guess I will try to find a 2-32 tap and hope it is the right size.

Joe
 

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make a tap with the screw size you have chosen.
cut a slot on the the side of the thread and solder the screw to a screw driver.
you still must back out and clean tool every 1/2 to 3/4 turn.
 

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I've ordered screws from Microfasteners a couple of times. The shipping wasn't very high, and I got them in a timely fashion. I did learn something the first time that I thought was kinda odd. The 1/4" flat head screws were 1/4" long from tip to head. The 1/4" pan head screws were measured from the tip to the underside of the head, making them longer than I wanted, and leaving me in a position where I had to cut off part of the threads to fit my back posts. I learned my lesson lfrom the first time I ordered, and learned another valuable lesson for the next.. Double check my order!! I got phillips head flat heads instead of slotted! :freak: Oooops!!
 

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screwpost tap

A ways back there was a guy (zachbuff I believe) selling an inexpensive post tapping tool on the bay. I think it was a self tapping screw encased in a resin handle. He got 3-4.00 a pop for them, and they were quite handy to have on the bench. Mine has held up well, though it's about 1/8" wider now with paint build up. It used to be my body holder when painting until I got the poster putty.
I contacted zachbuff and asked about him if he had any more of his cool screwpost tap tool's..
he said he will make some more ..I have one and told him I would buy another one if he makes some..

would anyone else like to get some ? it is a nice tool to have , they work great ..
I can let him know if anyone else is interested in getting any of them ...
 

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Discussion Starter · #19 ·
I contacted zachbuff and asked about him if he had any more of his cool screwpost tap tool's..
he said he will make some more ..I have one and told him I would buy another one if he makes some..

would anyone else like to get some ? it is a nice tool to have , they work great ..
I can let him know if anyone else is interested in getting any of them ...
It would depend on whether it cuts a thread useable by the screws I have. Do you know what size thread (screw size and thread count) the tool will cut?

Thanks...Joe
 
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