I thought I needed a hand tapping machine. I was wrong.
I was doing a lot of manual tapping, and it got tiresome. In theory, this is a great tool that allows for increased control and a straighter approach.
The way it works, you lock a tap in the collet, insert the collet into the spindle, lock your part into the adjustable vise, and then rotate the large handle. There’s an adjustable counterbalance for balancing the weight of the spindle. This lets you adjust the feel of everything.
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In testing, it worked great. In practice, my workpieces never behaved properly. Some were too long, others too tall, and the rest of the time I just didn’t feel like using it.
I thought I needed this. I wanted one for a while, and finally convinced myself to give it a try.
It hasn’t been used, and so it’s on the way out.
I have zero regrets – it was worth trying, and I’m happy I got a sense for how this and other such machines work.
I think mine would have seen more use if I had to tap a batch of parts in a row. In my testing, it really did deliver a nicer experience than common styles of tap wrenches.
One thing that surprised me is how heavy it is. The thread tapper has a solid base and frame, and operates quite smoothly. It worked pretty well for a no-name product.
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There are nearly identical tapping machines from Grizzly and other brands, and I imagine they work just as well.
frobo
I don’t own one of these either. In critical cases where I need the tap to start perfectly square, I use a trick I learned from old mechanic at work. I chuck the tap in the drill press, start the motor and then kill the power. While the machine is coasting down, feed the tap gently into the workpiece. That gets things started nice and square. I’ve never broken a tap doing this, but you have to be gentle, especially with small taps.
Bonnie
If it’s a traditional belt driven press I bet you could turn it manually a few times to get started straight as well.
MM
You can use this method to tap holes very precisely on a drill press or mill, all manually:
-clamp the workpiece & lock the table
-drill the correct size hole
-swap out the drill bit for a dead center
-Use the dead center to support the tap while you rotate the tap by hand. You can use a tap handle or turn it with a wrench. Keep constant down pressure on the dead center to keep the tap straight until it has cut a few threads.
-when finished, unclamp the workpiece
A short dead center you can stick in a drill chuck or collet is a handy tool for this. It’s just a cylinder about 3/8-1/2in diameter, ~3 diameters long with a conical point ground or turned on one end. They are easy to make from a dull or broken drill bit, end mill, a dowel pin, etc.
Matt C
I have my students make a tapping block out of 1×2 aluminium with holes that are slip fits for common taps. If you drill the right size holes it can be very convenient and they are quickly made with a drill press and scrap cutoffs in a pinch. I’ve seen this style and the biggest challenge I see if holding work pieces, which is why I like tapping blocks, they are easier to use since I can clamp a part in a vise and use the block on top of the part. I really like the clutched pneumatic tapping arms I used, but those cost ~$2,000, so hard to justify for home use
Stuart
You can also buy guides such as these – https://toolguyd.com/big-gator-tools-drill-guides/ . I’ve found that I can skip them if I have straight holes and start with a taper tap instead of plug.
Matt C
Stuart,
Those are nice. I teach in a CNC machining program, so we have student make the tapping blocks as a project
frobo
Stuart, thanks for the link to the Gator guide. I just ordered one. My bifocal glasses have a tendency to distort things a bit; more than once I’ve drilled a hole that looked square when I was drilling it, only to find out later that it wasn’t. This will help.
MM
The university machine shop I used to work in had one of those. I used it a handful of times, always whenever the milling machines were all occupied, but I’d much rather power-tap.
If you haven’t tried one yet, get your hands on a Tapmatic head for a drill press or mill. If you have to tap a bunch of holes quickly those are fantastic. They are also safe and don’t require the skill and attention that power-tapping with rigid setups does, as they usually have a built-in overload clutch so you don’t break taps and they auto-reverse.
Better yet is a metalworking drill press designed with tapping in mind. The type where the motor runs constantly and you use a clutch to engage forward/reverse on the spindle are great. If the spindle is balanced well you can tap very fine holes allowing the tap to feed itself, I’ve done as small as #4 on my 8500lb Carlton radial drill. Some even have power feed ratios which match common thread pitches.
Nathan
Why is the handle so big? What was the biggest tap it would take? Interesting
wonder if there are cordless tap or die runners. I know people use frills for them
MM
Anything bigger than about 1/2-inch in steel and you’ll be wanting a bigger handle. I don’t know what their capacity is but it’s bigger than what the handle is comfortable for.
I’ve never seen a cordless tapping machine but there are corded ones. I used to have a Bosch. They work like the Tapmatic head I mentioned above. You pull backwards and they automatically reverse rotation to back the tap out. They also usually have a special coupling where the tap mounts that can tolerate a little misalignment so it can self-correct if you don’t put the tap in perfectly straight.
fred
We did lots of refurbishment work in our fabrication shop – the yard and out in the field. Often the part to be tapped was too large to bring to the machine – and hand tapping was too tedious. We had a Bosch corded taping gun. It looked like a drill – but had a variable clutch. Push in and you tap, pull back and the tap would reverse. You could also feather the torque while driving.
Fein and Metabo seem to make a cordless version – but I’m not sure if they work the same way:
https://www.burnstools.com/fein-agwp-10-cordless-tapper-set-18v
https://www.acmetools.com/metabo-gb18ltxblq18v-tapping-tool-brushless-cordless-bare-tool-602362840/4061792188204.html