Hand Tapper Restoration

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Robert
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I bought this hand tapper on eBay

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It ended up being a lot rougher than I thought from the pictures. It had already been cleaned up to a cosmetic extent. The tap adapters were corroded to the point that the set screws would not come out and the taps were also solidly corroded in place. I put them in Kroil overnight and then tried without success. Finally I pulled out the old propane torch and heated. That actually worked quite nicely! I got the set screws out and drove out the taps with a punch.

Everything then got a bath in Evoporust. After some sandblasting and paint; here we are:

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This model is a 10S. For some reason it does not have the slot in the base for a work clamp. I have seen others that did. Does any one have one of these? I also have a question about the counter weight arm bearing. If anyone is familiar with these machines please respond!

Robert
 
Hello Robert,

You have done a nice job on that Lassy hand tapping machine. :encourage::encourage::encourage:

The idea behind the counterweight is that it will automatically lift the tap out on the last turn of the thread rather than you having to pull it out and breaking the last thread edge. Only really useful when tapping small holes with fine threads.
 
Shiny new tap adapters:

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This did not come with metric tap holders. I guess I will be making some. That piece of 12L14 in the back of pic looks suspiciously idle. I also need to replace the cracked wood holder. I have some teak that might work well.

Robert
 
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Hello Robert,

You have done a nice job on that Lassy hand tapping machine. :encourage::encourage::encourage:

The idea behind the counterweight is that it will automatically lift the tap out on the last turn of the thread rather than you having to pull it out and breaking the last thread edge. Only really useful when tapping small holes with fine threads.

My question about the counterweight arm relates to the disc on the end that rides under the shaft collar around the main shaft. On my machine this is fixed and does not turn as you rotate the handle. I am wondering if it has seized up and is intended to rotate? I am considering replacing it with a bearing but I would like to know the intended design.

This piece:

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Robert
 
Hi Robert,

I don't recall whether it rotated or not ! I think it may have done. You can get a clue by examining the underside of the collar for rubbing and removing the screw and seeing if it has a shoulder on it.
 
Thanks. There is no set screw. It seems to be riveted in place. There are rub marks on the collar but no flat worn on the disc at the end of the arm. This leads me to believe it should rotate. I think I will remove it and replace it with a bearing.
Robert
 
Hey Robert,

I have a hand tapper. It is just an inexpensive Phase II. I mounted mine directly to my milling machine base. I got tired of having to clamp it to my bench to use it. I also made a fancy tapping fluid cup to catch the run-off. Mine also has the slotted base for the clamp. I like it, I use it all the time.

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Hi Robert, Randy, Two replies :D

I'm surprised that it seems to be riveted in place, I thought that it was a screw securing the roller. Logically if it wasn't designed to rotate, why bother with a disc, it could just as easily be a lip on the end. The shaft can't rotate because it has a pivot pin through it.
So yes if it has seized, stick a small bearing race on the end.

Hi Randy,

I like the way you have set that tapper up, certainly makes it very convenient to use. I have to dig mine out every time I need it, its very heavy.
 
Randy-very nice setup! Does yours have a disc that rolls where the lever arm meets the shaft? I may go ahead and mill a slot in my base to make a clamp.
Robert

Edit: I messed with my counterweight shaft. The disc on the end is supposed to rotate. It was frozen. I was able to get it working with a little Kroil.
Robert
 
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Started on the metric tap adapters:

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The originals have a square broached portion of the thru hole near the middle of the part. I have no way to do that. My plan is to cross drill and thread the hole. Then introduce a set screw from each side so that they engage opposing flats of the tap shank. One on each side should retain the tap and prevent rotation. Any thoughts on this? The originals are hardened but I don't think that is really necessary?

Robert
 
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