Machined pengun - Dimply

[jackssmirkingrevenge]

Wouldn't have happened without your guidance moving to the next part!

[warhead052]

Maudit, I suggest you hurry or else your pen gun is going to be completed before you complete yours!

[LeMaudit]

warhead052.... my thoughts exactly

[inonickname]

JSR, did you use a lubricant to cut those threads? Or it could be that there's just some small chips or something left, or the photo just looks odd.

[jor2daje]

Just for the record you can't use a rear mounted cut off tool on the front side of the lathe unless you run it in reverse. Also looking good jack you'll be caught up in no time.

[jackssmirkingrevenge]

JSR, did you use a lubricant to cut those threads? Or it could be that there's just some small chips or something left, or the photo just looks odd.

Some chips. No cutting fluid so I used gun oil

Also looking good jack you'll be caught up in no time.

I am already, this beats watching epoxy cure

Next part not going to smoothly though, using the die in particular. I can't get the thread to bite, added a chamfer but it hasn't helped.

As you can see since I don't have a die holder so I turned down the other end of the rod so it will fit in the chuck and held the die in the chuck. (I'm just using it to keep things centred, not actually running the lathe )

What should the rod diameter for a 12 x 1.75 thread be? I couldn't find it online, it's currently down to 11.4mm diameter which is less than the minimum 11.701 diameter as I understand it... help?

[warhead052]

Jeez jack... You are machining pretty fast! Are you sure you have all the measurements correct and everything?

[jor2daje]

To get a good estimate you can measure the od on the tap.

That's a pretty good trick using the chuck to hold the die, but a fun project could be to make your own holder. It's a fun machining project to indicate in and cut the morse taper for the tailstock and it's very satisfying to use a tool that you have made yourself. I didn't buy the chuck from sherline and just used one I had lying around, I've cut a mt0 for the tailstock and a mt1 for the headstock with threads for a draw bolt. I also made a mt0 dead center, morse tapers should technically be hardened so I case hardened all my parts, but you could probably make do with unhardened or some softer metals.

Also silly thing but I'll say it just to make sure, are you starting the thread on the right side of the die?

[jackssmirkingrevenge]

Jeez jack... You are machining pretty fast!

From what I've seen so far, most of the work goes into the planning, and that's been done along the past few weeks.

a fun project could be to make your own holder

Was just discussing that with LeMaudit

Also silly thing but I'll say it just to make sure, are you starting the thread on the right side of the die?

I had assumed it goes in the wide part. Thanks for not taking anything for granted :-/

Managed to get it to work, but I abused the part so much that it's worth redoing, watch this space

[jor2daje]

One thing for next time is I normally don't do the quarter turn back to clear the threads until I'm at least a thread or two in.

[jackssmirkingrevenge]

Thanks for the tip Just sawed off another bit of rod, I might have enough for the body at this rate still, this is for practice eh

[jor2daje]

Also the chamfer looks to be at a bit too shallow of an angle.

[LeMaudit]

You need lubricant for taping. Use some petroleum distillate at least (paint thinner).

A chamfer should not be necessary. You insert the rod on the side of the die that is already tapered; normally the one with the markings. Looks like your setup is okay, I can see markings on the photograph.
You didn't fit one of the jaws in that groove on the die, did you? If so, your die may be off-center.

If could also be that your rod is off-center. Check that.

the diameter to use for a rod is the diameter of the thread minus 0.1 to 0.2mm, depending if you want a tight fit or not. It should never be above the intended thread (in your case, 12 mm). The closer to 12mm, the harder it will be to tap, and the more you will need lubricant. As a rule, don't thread without lubricant, you'll wear off the die (though with brass it is less of a problem than steel I believe).

Also, jor2daje is right. Look at my videos, I cut for a quarter turn, then go back. This is to break the chips so you can continue turning and cutting without everything being stuck.

[jackssmirkingrevenge]

A chamfer should not be necessary. You insert the rod on the side of the die that is already tapered; normally the one with the markings. Looks like your setup is okay, I can see markings on the photograph.

That's what I thought, but it just isn't biting.

You didn't fit one of the jaws in that groove on the die, did you? If so, your die may be off-center.

No, I was careful about that.

If could also be that your rod is off-center. Check that.

It turns true in the chuck.

the diameter to use for a rod is the diameter of the thread minus 0.1 to 0.2mm, depending if you want a tight fit or not. It should never be above the intended thread (in your case, 12 mm). The closer to 12mm, the harder it will be to tap, and the more you will need lubricant. As a rule, don't thread without lubricant, you'll wear off the die (though with brass it is less of a problem than steel I believe).

As usual, it seems lack of lubricant is the problem

This is costing me a lot of brass

[dewey-1]

Thanks for the tip Just sawed off another bit of rod, I might have enough for the body at this rate still, this is for practice eh

Heres is a handy tapping and using tapping dies guide.
http://www.tapdie.com/html/hints_on_tap ... dies_.html

It is about time you are using a lathe!
How many years ago did I tell you to get a damn lathe?

Notice that I spelled tapping correctly, not taping! Hint Hint LeMaudit
There is a difference in tape and tap!