MrBeans adventures in making a tap and nut.

[MrBean]

Having trawled these forums last night for some info on making a tap, I thought I'd post my attempt. I know there's more info on the Zone than I turned up last night, because I've seen it before, but it was evading my search this time.

I have 3 and a half lead screws of as yet, unknown pitch. They came with small plastic (Nylon I think) nuts, that aren't big enough to attach to a linear axis. I think I would have a hard time trying to obtain a tap that matched the screw, so I'm making my own. The nuts will be made from delrin.

I'm not sure if there is a "right" way to go about this, so I just jumped in and started hacking away. First off I mounted the screw in my drill press, with a bearing in a vice at the bottom (un-chucked end), to hold the screw from floating around. See the pic, it'll make more sense.
Happy that the screw was running nice and straight, I started to carve a taper about 6 inches up from the vice using a handheld angle grinder. The lower portion of the screw, is the bit that will become the tap.
Once I had a basic taper I was happy with, I removed the screw from the drill press and hacksawed the peice off that will become the tap. I now chucked this smaller length in the drill press and tidied it up a bit with a file and some emery paper.

That's about where I'm at at the minute.

If anyone has any useful tips or advise that might help, that would be great.
I'm wondering if the taper is a bit coarse/steep, should it have a longer/shallower angle?

I'll either cut the flutes later today or tomorrow. Depends on time.

[santiniuk]

Hey slacker,

My eyes must be deceiving me

Are you finally getting your ass into gear and making the nuts for the screws and bearings I donated to you back in July !

Oh yes I remember the conversation well. 'Lets make a small pcb router I said. I have a few spare screws and odds'

"Yes ! you said. I'll make the nuts this weekend"

Well it's only 5 months late but at least some progress has been made.

I will search my drive for the cad models we started on our joint venture...

roll on

Pics attached to remind you of what we started....

Are you sure the taper is long enough ????

[handlewanker]

Heath robinson is alive and well!
Aint yo' got a lathe?
Ian.

[MrBean]

Yeh I have a lathe, but it's not set up.
And I'm lazy too.
One the one hand, I can't be bothered to produce Gcode to make the tap flutes using CNC, but then again I cant be bothered to stand and turn the handwheels on the manual mill either.

Decisions, decisions.

So far, Heath Robinson is working well.

Anyway... What's with the name Ian....... Handlewanker???

Regards Terry.

[handlewanker]

Hi Terry, the name is a common nickname for a turner, hence Handlewanker.
Been doing it on and off for 40 years, turning that is, now I do it for myself.
Pride and joy is an old Colchester Bantam, 1930 vintage, bought in UK in 1981 for 100 pounds, and shipped to OZ when I 'migrated.
I recut the bed with a hand planer get-up and rescraped it to fit the saddle.
The bed had .013" wear in it from halfway down to the chuck end.
I wish you luck with the "tap" exercise, it would have been quicker to cut it in the lathe, but there you go, have fun.
Ian.

[MrBean]

Thanks Ian. I had a strange image in my head regarding your username. You have put my mind at rest.
I'm not good with a lathe I'm afraid. My boxford has no drive at the moment, and if it did, I don't have the room to have it permanently set up. So drill press and angle grinder it was. I'm off out to the garage now to cut some flutes.

Pictures comming soon I hope.....

SantiniUK. If all goes well, I'll post you some new nuts. Delrin. Much tougher than those flesh and blood one's you've got.

Regards Terry.

[MrBean]

I have cut the first flute in the tap. It went fairly well. I made a quick gcode to save me staying out in the cold turning handwheels.

The pics make it look worse than it is. The flash seems to show up every mark and scratch.

The screw diameter is 12mm, I cut a 3mm wide flute with a flat end mill. I might try a 3mm ball ended mill for the other flutes, and go a little deeper.

[MrBean]

Well I got the other flutes cut today using the ball end mill. It looks much better than with the flat ended cutter. I went slightly deeper too.
Now I just need to find an scrap of delrin to try it on.

Here's some pics of the tap.

Regards Terry...

[10bulls]

Hey slacker,

My eyes must be deceiving me

Are you finally getting your ass into gear and making the nuts for the screws and bearings I donated to you back in July !

You can talk Mr Steven bloody Speilburg!!! You're supposed to be project manager but all you've done since is compile your video compilation of kids falling over for nan's christmas pressent. Typical upper managment!!!!

At least I've got an excuse! And I have been thinking about it. A lot!
....and I drew that ballscrew picture!!!

Anyway...

This thread has got the potential to be about the most brilliant. ever!
With someone called HandleWanker in it's bound to be.

G'day HandleWanker

You've done a reverse of what I did. I migrated the other way. Thus proving Newtons third rule of motion.

Get bodging lads!!!

[ger21]

This thread has got the potential to be about the most brilliant. ever!

I'll second that.

[MrBean]

Yay. The whole gang is here. Well I'm pretty pleased with how the tap works. It's ever so slightly loose on the screw, but there are still some burrs from milling the flutes in the tap, which when cleaned up should leave the nut fitting a bit nicer. I still want to make a double nut with some kind of springy doo dah to preload the nuts against each other. Still looking for something easy to acheive that.

There's not much room on the tap for swarf/chip removal. The flutes could do with being a bit wider to help with that, but it works rather well if you take it slow and steady.

Regards Terry.

[Oldmanandhistoy]

Hi Mrbean,

Your tap looks good, this is how I made mine (see pic) should explain. It’s about 200mm long with a gradual taper up to about 150mm. Made it for my 12mm, 6mm pitch, 2 start trapezoidal screws. I use it in my cordless drill and cuts a nut in two goes (after they have been in the freezer).

John