Tap sizes needed

[Texatdurango]

I'm wanting to tap some acrylic blanks to hold some nibs, has anyone found the correct taps to use with these nibs?

From left to right they are the replacement nib and the standard nib sold with the junior size pen kits, both from Craft Supply then the El Grande nib.

It appears that the El Grande nib may be a metric size 10-1 but I haven't found a tap yet to verify the size.

Visiting several specialty tool supply houses in town didn't shed any light and I'm trying to get some answers from a few online tap and die stores but could use any help from those who might have already been down this road.

 

[CharlesSharp]

Get a pitch gage to check the thread spacing and then measure the diameter with a pair of calipers or a micrometer.
That should give you everyting you need to purchase a tap.

 

[DCBluesman]

http://www.penturners.org/forum/topic.asp?TOPIC_ID=29700&whichpage=1#303669

 

[Texatdurango]

Originally posted by CharlesSharp

Get a pitch gage to check the thread spacing and then measure the diameter with a pair of calipers or a micrometer.
That should give you everyting you need to purchase a tap.

I wish it were that simple but it's not... as far as I can tell!

Measuring the major diameter of the threads on the Craft Supply nib holder reveals .328" or 8.3mm.

After spending the past few hours pouring over dozens of thread charts, I've come to the conclusion that these threads are neither standard ANSI or metric threads since the closest ANSI diameters are:

5/16 = .312"
11/32 = .343"

And the closest metric threads are:

8mm = .315"
9mm = .354"

The closest thread size I found is a specialty Brass thread size of 5/16-26 which is close to the thread per inch count but a bit to narrow.

After seeing several folks making custom pens on the forum and obviously tapping their own blanks for these nibs, this must be one of those "held close to the vest" secrets that is not easily shared!

 

[CharlesSharp]

I'm still sticking to my first post. Once you know the pitch and the major dia., you can track it down. Also, is it a single thread?
Get me the info and I'll see what I can do.

 

[KenV]

The answer is not a simple one, and the creation of high quality threads, particularly multi-lead threads is not the simple tap and die situation common with common bolts. Precision lathe work and/or CNC mills are the sorts of tools used to make this kind of thing work. It is a matter if investing time and dollars in the skills and gear -- but multilead threads are a bit of a challenge.

 

[dachemist]

I realise these are not the same nibs asked about in the original post, but for what it's worth I found the 1/8-NPT from this set http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=45766 works well (though I haven't figured out how to make a cap to go over it, but I've only tried once).

nibs: http://www.arizonasilhouetteinc.com/cart/index.php?main_page=product_info&products_id=1062

The ones on the right with the gold band near the nib.

 

[bgray]

The external threads on sections going to the barrel can be pretty sloppy, and still work well.

If you want evidence of this, insert your CSU section into the nib holder, and check out the play. Most of them are pretty bad. But once you snug these down, the play doesn't really effect the performance of the pen in any way. Threads can be VERY sloppy and still function.

These don't have to be aerospace-grade threads....I would measure your major diameter, your TPI, and then see if there is a cheap tap that is in the ballpark. But custom taps and dies get pricey.

Also...when you start pricing custom taps and dies, it only takes a couple of sets to equal the price of a small 7x metal lathe...

 

[DCBluesman]

Originally posted by Texatdurango
After seeing several folks making custom pens on the forum and obviously tapping their own blanks for these nibs, this must be one of those "held close to the vest" secrets that is not easily shared!

Unfortunately, George, this seems to be an area that is not readily shared.

 

[IPD_Mrs]

George,
Why not take the nibs to a hardware that carries loose metric nuts. Try them until you get the right size and then you should know what tap size you need. If this idea works a PM with the information would be really nice.

Mike

 

[gwilki]

I don't have any of the junior kits or el grande right now. But the threads on an emperor are 10mm x .75. I think that the juniors are the same, but maybe someone else could confirm that.

 

[jhs494]

Often times manufacturers will make custom or bastard threads that are not something that an off the shelf tap or die will match up to.
This makes it so you the consumer cannot interchange or easily reproduce what they are producing.
What you will find is that because the length of thread engagement is so short you MAY</u> be able to find something that is close and will work, not the best solution but it will work.
The one thing that must be looked at, is it a multi lead thread. This has been stated before. This thread is used for speed,so you are not screwing on all day long. The nib section that you are asking about should be single lead thread.
I agree that the El Grande is an M10 X 1. That is the only one of the three that I have in stock. If you can wait I will check on Monday at work and let you know after tapping and testing it to confirm that an M10 X 1 will work.

Look at www.mcmaster.com they have a wide selection of metric taps.
There are not that cheap.