First facing cut - carbide insert - 5/8" brass round

[Janderso]

Nice of John to beat me to it, I was going to say something along the lines of, "is that carbide insert going to hold up against brass?"

Brass is special in that it likes a flat-topped tool and a near 90 degree edge.

I also have this set. Would any of these be ideal?

That’s a great starter set. It sure saves a ton of time.

 

[Janderso]

What’s amazing is just how endless the need for a tool is, lol. Like everyone else I was warned about the cost of tooling, but my god. Every step forward is 2 back with one hole now needing a #52 drill bit and another a size Q drill bit.

You’ll really be cooking when you have spent more on tooling than you paid for the machine.
Ask me how I know

 

[ssdesigner]

You’ll really be cooking when you have spent more on tooling than you paid for the machine.
Ask me how I know

Ha! I hear you. I'm inching closer each day

 

[ssdesigner]

Ok, almost done with my first project: The Scribe

My last question on this is the threaded cap. Attached are a series of photos showing how my cap doesn't quite screw all of the way on to the scribe body. It's short by about 1/16" or so (sorry metric folks)

So I tested it on my thread checker and the culprit seems to be the cap? The body of the scribe snugs tight on my thread checker, but the cap seems to stop short enough to make me think that it needs adjustment? Thoughts?

Also worth mentioning, I did use a parting tool on the male end of the threads to create a solid shoulder, so that may be why I get a nice snug fit on that end with my thread checker.

 

[G-ManBart]

My last question on this is the threaded cap. Attached are a series of photos showing how my cap doesn't quite screw all of the way on to the scribe body. It's short by about 1/16" or so (sorry metric folks)

So I tested it on my thread checker and the culprit seems to be the cap? The body of the scribe snugs tight on my thread checker, but the cap seems to stop short enough to make me think that it needs adjustment? Thoughts?

How did you form the threads in the cap? If you used a tap, what kind? The most common form of tap (what you find in most sets) is a plug tap and those won't thread all the way to the bottom of a bore. For that you need a bottom forming tap. Start with a taper tap or plug tap, then finish up with a bottom forming tap.

 

[ssdesigner]

How did you form the threads in the cap? If you used a tap, what kind? The most common form of tap (what you find in most sets) is a plug tap and those won't thread all the way to the bottom of a bore. For that you need a bottom forming tap. Start with a taper tap or plug tap, then finish up with a bottom forming tap.

Here is my tap.

 

[G-ManBart]

Here is my tap.

Yep, that's a plug tap....you can see how it tapers from front to back. You'll need a bottom forming tap to make the threads go deeper into the bore (they don't get 100% to the bottom, but close).

 

[ssdesigner]

Yep, that's a plug tap....you can see how it tapers from front to back. You'll need a bottom forming tap to make the threads go deeper into the bore (they don't get 100% to the bottom, but close).

So something like this one:

https://www.mscdirect.com/product/details/09833732

 

[piper184]

The other approach to this is to remove some of the threads at the end of the body where the cap screws on. The idea is to make the body look like the tap that was used to thread the cap.
In this application I would think that one or two threads to retain the cap would be sufficient since there is no real clamping force required from the threads.
Put the tap in the lathe and adjust the cutting tool and compound until you can follow the taper (not under power of course) the gently remove the threads of the body until they fit into the cap.
It would save buying a specialty tap for this one project. Although in that size it may be one you want to add to your arsenal anyway.

 

[G-ManBart]

So something like this one:

https://www.mscdirect.com/product/details/09833732

Sort of. That would probably work, but if you notice, it has "H4" in the description which means it's slightly oversized....the higher the number the more oversized they are and each number overlaps in tolerance. The tapping world can be a rabbit hole with many subtle differences.

I've been buying US made taps off eBay from a seller here in Michigan with good luck. I just bought a 2-pack of 3/8-24 and they're nicely made....H2 so only a tiny bit oversized.

Morse 3/8-24 STI Bottoming Tap HSS H2 4 Flute Taps 2 Pack 34077 | eBay

MORSE CUTTING TOOLS. H2 - 4 FLUTE - HIGH SPEED STEEL.

www.ebay.com