Tapping threads into steel plate

[ARCHIVED THREAD] - Tapping threads into steel plate

Posted: 3/13/2005 1:03:39 PM EDT

I'm considering building a hydraulic bullet sizer for those pesky steel core 50 caliber bullets.

Everything seems pretty easy, except for one thing.

How does a person tap a hole in a steel plate and keep the threads perpendicular to the plate?

This seems virtually impossible for the shade-tree grease-monkey.
Especially when you are talking about a 1.5" diameter hole in a 1" thick steel plate.

Are there machines out there that can do it?
If so, what are the odds that I could find a shop that could do it for me?

Thanks,

Dave

Posted: 3/13/2005 1:06:29 PM EDT

[#1]

Do you have a drill press? You can start the tap in the chuck, NOT WITH POWER, and once it gets started change back to the tap handle. If course, if your hole is perp your threads will be too.

ByteTheBullet (-:

Posted: 3/13/2005 1:07:39 PM EDT

[#2]

Any machine shop can drill and tap a hole for you, you can to it is easy.

You need the correct sized drill bit, to corraspond with the tap. Be sure to use a Starter tap, T-handle for the tap, a tap guide, that will help kep you straight, and some cutting oil.

Also use a good tap, not a cheap carbon tap.

Posted: 3/13/2005 1:07:50 PM EDT

[#3]

You will need someone to do it. An 1.5" tap would run you $150+

Posted: 3/13/2005 1:09:05 PM EDT

[#4]

Quoted:
You will need someone to do it. An 1.5" tap would run you $150+

Heck, I spend that much on taps easy, but then again, it is needed for my job.....

Posted: 3/13/2005 1:13:58 PM EDT

[#5]

Quoted:
You will need someone to do it. An 1.5" tap would run you $150+

Holy crap, you are right.
McMaster has them for $134.
Ouch.

Yea, for this project I would be better off having someone else do it.
I've never had any other use for a 1.5" tap.
Probably never will again.

What kind of business would most likely be equipped to do this?

My company has a machine shop, but we don't have taps of this size.

Just any old machining for hire type shop?

Thanks again

Dave

Posted: 3/13/2005 2:18:20 PM EDT

[#6]

Think yellow pages and a phone.

Posted: 3/13/2005 2:48:27 PM EDT

[#7]

Any shop with a lathe that has a faceplate setup can easily cut the internal threads that you need. They'll probably want you to bring the part with the threads for test fitting.

If you supply the plate, I would guess they would do it for under $50.

Posted: 3/13/2005 2:58:05 PM EDT

[#8]

Cutting the threads on a lathe would preclude the need for an expensive tap. If the plate is too big to chuck or mount on a faceplate, consider drilling/boring and threading a piece of bar stock as a "nut" and then fasten it to your plate after threading.

We've got a large radial arm drill press in the shop at work that is great for large tapping jobs. It has a slotted table for hold downs. I use a lathe center in the back of the tap to keep it straight. I can apply down pressure while turning the tap with a large t-handle or crescent wrench.

Posted: 3/13/2005 3:28:30 PM EDT

[#9]

I am not exactly sure what he is making, but could he weld a big ol' nut to the plate?

ByteTheBullet (-:

Posted: 3/13/2005 3:56:58 PM EDT

[#10]

Quoted:
Any machine shop can drill and tap a hole for you, you can to it is easy.

You need the correct sized drill bit, to corraspond with the tap. Be sure to use a Starter tap, T-handle for the tap, a tap guide, that will help kep you straight, and some cutting oil.

Also use a good tap, not a cheap carbon tap.

He said he needs it perfectly straight. Perpendicular. It's not easy to do that without a jig of some kind.

Posted: 3/13/2005 4:15:26 PM EDT

[#11]

Quoted:
Quoted:
Any machine shop can drill and tap a hole for you, you can to it is easy.

You need the correct sized drill bit, to corraspond with the tap. Be sure to use a Starter tap, T-handle for the tap, a tap guide, that will help kep you straight, and some cutting oil.

Also use a good tap, not a cheap carbon tap.

He said he needs it perfectly straight. Perpendicular. It's not easy to do that without a jig of some kind.

BAH, Do it all the time at work.

Posted: 3/13/2005 4:19:53 PM EDT

[#12]

If the hole in a 1" thick plate is perp the threads will be too. Don't rush it, it will take some time.

ByteTheBullet (-:

[ARCHIVED THREAD] - Tapping threads into steel plate

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