book collections email follower instructable user
Picture of Manual Thread Tapping Machine

Sometimes a project gets made because the right materials and/or components appear, Such was the case with this hand tapping device, the construction of which forms the basis of this post. Except for the Irwin tap holders everything came from the scrap box (I prefer to call it the rainy day collection)

For quite a long time a hand tapper as featured here has been on my rainy day to do list but it had never risen to the status of do it NOW, That is until out of the blue it occurred to me that parts of my old Russian photo enlarger (from pre-digital camera days) provided most of the bits that I would otherwise have to make. I knew that it would come in handy one rainy day.

There are many ways to tap a thread but here we are concerned with hand tapping. The biggest problem with hand tapping is holding the tap square to the workpiece. There are various devices which can be made or bought to help in this area and the type of tapping machine described here is but one. It is suitable for many tapping jobs but not all. Often machines like this are made with a fixed frame which limits the height of the workpiece. I wanted a device which would handle a much larger range of jobs and that is what the old enlarger support offered.

The final step in this instructable links to a video of the process and the reader is advised to watch that.

I have entered this post in the "Trash to treasure" contest so if you like it please vote for it.

Step 1: Materials and Tools

Picture of Materials and Tools

The only "bought in" item for this project was the Irwin Hanson 3/8" drivetap holders pictured above. They come in pairs for small and larger taps. I got mine from this Amazon link

As I mentioned in the intro. everything else was what I had laying around. Of course everyone who wants to make a similar tool will have different stuff in their scrap bin and so the detail design can easily be adjusted to suit what you have. Even if all material had to be bought the cost should still be reasonable.

The project has three main parts as follows:

1. The base. Comprised of some angle iron and a piece of steel plate.

2. The frame. I used parts from an old photo enlarger. There must be plenty on the usual "for sale" websites, if you have not got one. Alternatively a simple clamp could be fabricated from steel tube or machined from aluminium.

3. The shaft or spindle and bushing. I had a short length of Thomson shaft 1" diameter which was ideal. Thomson shaft is hardened and ground on the outer surface but is softer in the middle so it can be drilled. Unhardened steel shaft would do fine unless you were using the tapper so much that wear would be a problem.

Tools needed

Welder - I used MIG for the base and the add-on piece for the enlarger. TIG or stick would do just as well.

Lathe - used to make the sleeve for a bronze bush.

Milling machine - This is useful but not essential. I used it to true up the base because my starting piece was so out of true.

Drill press, vertical milling machine or pistol drill - for drilling a few holes.

Any tool suitable for cutting steel for the base. I used an angle grinder with a thin cutoff blade but a bandsaw, plasma cutter, laser, waterjet, milling machine or hacksaw would be fine also.

Usual hand tools.

Honus4 months ago
Splendid work on making a really useful tool! I bet I know where I can obtain an old enlarger... Also should order a new copy of your book as I loaned mine out quite some time ago and it seems to have disappeared forever- it was of huge assistance to me many, many years ago when designing suspension mountain bikes.
tonyfoale (author)  Honus4 months ago
You wouldn't believe how many times I hear that story. Lending books should be renamed losing books. I have always been surprised at how many people use my software for mountain bikes,
CPUDOCTHE1.4 months ago
That is a nice looking build. I have thought about building something similar or just sleeves that go over taps to hold them perpendicular. The last big tap job was 21 holes each in two pieces of 1/4"x2"x108" cold rolled steel for 10-24 bolts. I drilled each hole in the drill press, slipped off the drive belt, put the tap in the chuck and then turned the spindle by hand to tap the hole. The tap lined up exactly with the drilled hole that way. It was kind of slow but worked.
throbscottle4 months ago
So impressive! I didn't even know such a thing existed. Just what I need for the occasional small hole. Don't think improvised tooling would be up to making one like yours. Maybe I could make a sleeve + stand for my mini-tap holder. Voted, anyway :)
RandalR14 months ago
Great build. Really clean and professional looking.
I bought one the Grizzly G8748 ($129 on sale) because I needed to do a lot of repeat tapping and didn't have much time. And then I ended up buying the Irwin sockets youve shown, and a small Harbor Freight pneumatic impact wrench to power them instead of using the manual handle.
Grizzly G8748.jpg
tonyfoale (author)  RandalR14 months ago
I have used those grizzly machines. They work quite nicely. I generally use mine for small taps 6mm and smaller and for those I prefer hand tapping. For a lot of larger holes The pneumatic drive sounds fine.
I have two reversing tapping heads that I can use in a drill press or milling machine. I still use them for some jobs but the convenience of the hand tapper is hard to beat for most of my jobs. I do not do any production work and most is one off rather than repetitive.
Wow! I certainly wouldn't drive a tap with an impact driver. You must only drive very large taps.
RandalR1 JohnW8394 months ago
Funny you should say this as I was just tapping some 10-32 x 1/2" deep holes in a cast table this morning. As I was working under the machine and had limited clearance I wouldn't have been able to use a standard tap handle. So I used the impact wrench. This was the first time using it on a small tap, and I have to say it did way, way better than I ever thought. The first one had me clenching pretty tight as I had never used it on anything less than 5/16-13. I just sprayed a little WD-40 on the tap and feathered the butterfly valve, and it drove the tap straight up with no stopping or backing up to clear the threads.

I think it's like impact drivers for drywall type screws. Before they existed I broke many a screw with my cordless drill. But now with my impact driver it seems I never break them.

(I thought I bought the Harbor Freight model but I actually bought the Husky 4410 because I liked the way the air input swiveled.)
JohnW8394 months ago
That's a fantastic project. Wish I had your skills and machine shop, but unfortunately, I have neither. Also don't have a "scrap bin" with anything more that an assortment of screws, bolts and nuts and perhaps a spring or two. Great Job on the video too.
tonyfoale (author)  JohnW8394 months ago
My scrap box is quite large, I rarely throw anything away. It has to be real useless scrap to get thrown out. Those parts of the enlarger must have been waiting well over 20 years but I knew that one day......................
fjr_scoot4 months ago
Very nice!
Fastnate4 months ago
This is cool. Nice work!
carl5blum4 months ago
Nice job!
I made one back in 1977 using this tap wrench:
It was 25 years before I got sloppy and broke a single tap in it. I wouldn't be without it.
jessyratfink5 months ago
Really nicely done! What a great reuse of materials :)
tonyfoale (author)  jessyratfink5 months ago
Glad you like it, thanks for the comment.
johnip45 months ago
I have something similar. Instead of the tap sockets (I didn’t know they existed) I used one of these from grizzly tools
tonyfoale (author)  johnip45 months ago
Many people do not know of their existance, I only found them by accident.
I bought those 5 years ago because I liked the ability to use the variety of 3/8" socket drives available, especially ratchet ones. I never thought of them for a tapper like this at the time but when I was looking through my collection of tap holders for inspiration I saw them and knew that they would be ideal and I can still use them normally.