Field Expedient Transfer Screw

I've simply turned cup point set screws in backwards with needlenose pliers and then punched as close as I could in the center of the small circle they make.

For those that don't care to do the search. Something to make on company time for company use. Sweet.

Wes

Another thing I had no idea existed....(it has to stop soon, surely)....looked them up on Google, the best explanation I could find was

"8-32 TRANSFER SCREW SET .A fast and precise way to transfer the exact location of open and blind threaded holes to mating parts.Just insert the screw with the point sticking up,locate the piece being marked on top and tap lightly.Hollow handle is both a wrench and a storage holder.Set includes one handle wrench and six screws which store inside the handle when not in use"

I think you screw the transfer screw into the hole, set it up so its just proud of the surface, position the bit you want to tap on top, and then whack it. Am I correct? -

And how did you get an allen key socket into the tool holder shaft? - is there indeed one, you mention drilling and tapping the toolholder, but how does it engage the allen head on the transfer screw?

whats a typical use for them, is it in maintenance/repair rather than manufacturing? , are they widely used, or infrequently- curious about this one (and lot of other things as well, thanks be to RCM for answers, in the past and hopefully future...)

Andrew VK3BFA.

Aye, that's a great technique, thanks!

Jon

wrote>

You got it right on, that is exactly how they are used. As for the tool holder, I should have mentioned that the hole down the middle of the threaded rod was tapped to 10-32, and a setscrew was screwed into this, with the Allen head facing the business end.

I then ground the diameter of this set screw in the holder so that it would fit *inside* of whatever threaded hole that was using the transfer screw in. I would have done a better job at reducing the diameter of the set screw in the holder, but the abrasive wheel in my bench grinder has surfaces which are, shall we say, "less than square." :)

Jon

Here is how I make my spotting screws:

1) Chuck a piece of brass rod 3/8" dia. x 1.5" long, face, centre drill, tap drill all the way through, and tap required thread as deep as possible.

2) Remove from chuck and thread in a short socket head set screw with the socket into the hole. Use hex key through the hole to retract this screw as far as possible.

3) Screw in the set screw to be modified into a spotting screw; use a pair of flat nosed pliers to screw it in, leaving about 1 dia. projecting from the brass rod.

4) Use the first screw to jam the second screw tight.

5) Re-chuck and turn or file a 60 - 90 deg. included taper point on the end of the screw. On screws such as 10-32UNF or smaller I file this point.

6) Set one chuck jaw horizontal using level from test square, and file a flat on the top of the taper point.

7) Turn the chuck 180 deg. using the previous level to verify the 180 deg., and file an opposing flat on the screw point. Repeat this filing on both sides until about a 1/16" wide flat portion with the point in the centre remains.

8) These are the wrench flats and I use a small, pointy, needle nose plier to screw the spotting screw in and out of the work piece. On a through hole the hex key may be used; on a blind hole the needle nose pliers are required.

I have used these screws as small as 4-40UNC. Smaller ones are possible but then an appropriate wrench, along the lines of a tire valve wrench, would need to be made.

These screws are remarkably tough and can be used many times on brass, aluminum, and a limited number of times on mild or annealed steel. And they are easily replaced.

Wolfgang

I've used them to mark the drill holes to mount a potted power supply with blind female threaded inserts to a panel, when I didn't have the tools to do a layout or the data sheet with dimensions. They can also be used to measure to the centers of tapped holes.

Wolfgang's suggestion is good for a lot of things. I made several drill rod cylinders with carefully centered male or female threads for custom mods to nuts and bolts. In my experience tapped brass electronic spacers are concentric enough for most work. Aluminum spacers are too soft to make more than one or two parts.

Jim Wilkins