0.3 and 0.5 mm Pencil Kits?

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penicillin

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Lurking for several months, but this is my first post.

Does anyone know if pencil kits are available with 0.3 mm or 0.5 mm pencil leads? So far, all I have found is 0.7 mm and up.
 
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Curly

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Welcome to the forum. Go to the Introductions area and post a hello there. You’ll be eligible for a random prize at the end of the month.

I don’t know of any .3mm kits.

The Mistral kit from Beaufort Ink has an option of either .5mm or .7mm lead. Turners Warehouse sell them too. There should be some other brands but I don’t know which.
Disclaimer. My wife Marla makes Blanks for both companies.
 

darrin1200

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BSea

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I have only done a couple. There are a few in kits in .5, but none in .3mm or .9mm.
When I needed to make those sizes, I had to go to the pentel conversion. Punch that into the forum search and you will find some good references and discussions.
Here is a couple

http://content.penturners.org/library/pencils/pentel.pdf
http://www.penturners.org/forum/f14/pentel-pencil-conversion-101-a-46017/
Plus 1 on this. I just made my 1st conversion. And the Pentel comes in 3, 5, 7, and I think 9. Just search on Amazon for pentel pencils .3

Here's 1: https://www.amazon.com/Pentel-0-3mm-Mechanical-Pencil-Barrel/dp/B000WH2WSO/ref=sr_1_9?crid=11IV943F8DS8Q&keywords=pentel+mechanical+pencils+0.3&qid=1551620570&s=gateway&sprefix=pentel+mech%2Caps%2C173&sr=8-9
 

monophoto

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I've done several of these conversions, and there are a number of posts on this board describing how various members have done it (here's one example).

The process is not difficult, but it is an exercise in careful machining. The critical issue is that a stepped hole is required to receive the Pentel mechanism, and the dimensions at the tip end of that hole must be precise; the end of the mechanism is a threaded tenon, and the end of the hole must have a matching diameter, and more importantly, a depth that allows the metal end of the pen to screw onto that tenon to hold everything together. Also, these two holes must be exactly concentric; the slightest misalignment in these axes causes stress on the pencil lead, and the fine lead used in these pencils is extremely fragile.

The traditional approach is to drill a stepped hole from the plunger-end of the pen, using one bit for the larger diameter, and then using a special long-shank bit for the smaller diameter. It is possible to drill in two steps from opposite ends of the blank, but to achieve the precision required, it is critical that the axis of the blank be maintained exactly for both mountings. I was never able to achieve that accuracy when mounting the blank in a scroll chuck, but I think it might be more possible if the blank is turned to a cylinder, and then mounted in a collet chuck.
 
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penicillin

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Thank you to all for sharing your experience with great input and comments. You helped me find what I could not find on my own through web searches.

Lacking a better web search, I started down the Pentel path independently. I didn't realize that I was re-inventing the wheel. I have known and used Pentel P205 0.5 mm pencils for decades. I went to the art supply store and looked at a lot of mechanical pencils, concluding that the ONLY one that might work is the Pentel P205 type. The others all had threads and other protrusions in the tube that were an integral part of the retention and/or operating mechanisms.

I took measurements of a Pentel P205 mechanism with a caliper. A couple days ago I bought small brass washers. I felt that wood might not provide a sufficiently strong, firm seat for such tiny "wings" in the mechanism. I like the small outer diameter of the washers, which should fit easily inside a wood pencil tube, but I'll have to enlarge the inner holes slightly. I will make a small drill hole jig to hold the washers while I use twist drills to enlarge the inside diameter. We'll see. I may have to find smaller washers.

Continuing my plan, I will drill a pen blank with the small exit hole for the part where the screw threads on the nib attach, then again with a stopped hole for the mechanism. I'll turn the wood between centers, glue the washer in the base of the mechanism hole, assemble it, and PRESTO! - I'll learn what doesn't work and needs to be fixed or altered. I will figure out a different clip solution, if any. I like thin pens, but don't need these pencils to match the Pentel outside exactly. Besides, the Pentel clips are ugly.

In case anyone can use them, here are my incomplete measurements:

Hole size for pencil tip threads: 3.95 mm
Hexagonal seat size between flats: also 3.95 mm
Hexagonal seat size between corners: 4.45 mm

Basically the pencil mechanism relies on the 0.25 mm angled "wings" at each hexagonal corner to seat. (4.45 - 3.95 mm) / 2 = 0.25 mm. The wings are not fully supported, either. The total cross sectional support area seems very small to me, and I wonder if even very dense hardwoods are strong enough to hold that lip through heavy use. That's why I thought of using brass washers as a seat for the mechanism. We'll see.

I don't have the rest of the measurements yet. If I succeed, I'll post instructions on how to duplicate my work.

I know what I like in 0.3 mm and 0.5 mm pencils, but I want to make them in nice wood versions. There is an indescribable quality to wood pens and pencils that cannot be replicated with ordinary commercial products. That includes pride in workmanship. It may be nothing more than self-indulgent vanity, but I like to think that it is worth the effort anyway. :)

In the meantime, I have already looked at the links and instructions that you posted above. Thanks again and please keep them coming. I plan to make a few of the recommended kits, too.
 

Curly

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Some of the vendors sell the Schmidt DMS 2005 thru 2008 mechanisms that replaces the Parker type ink refill to make a pencil. They come in 0.5, 0.7 and 0.9 sizes some being twist and some click type. I've never tried them personally so can't say how well they work.
 

brailsmt

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I completed every single math and physics homework assignment in college with a pentel 205. I have wanted to ask this same question, but haven't got around to it. Thanks for asking for me.
 

BSea

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Basically the pencil mechanism relies on the 0.25 mm angled "wings" at each hexagonal corner to seat. (4.45 - 3.95 mm) / 2 = 0.25 mm. The wings are not fully supported, either. The total cross sectional support area seems very small to me, and I wonder if even very dense hardwoods are strong enough to hold that lip through heavy use. That's why I thought of using brass washers as a seat for the mechanism. We'll see.
Your right, this is a critical area. Here's how a buddy of mine does it, and I followed his idea.

1st, we use a 3/16 long drill to drill through the entire blank. Then we follow that with a 1/4 to a depth of 3.66 inches. This depth isn't extremely critical, but it can't be too short, or the push button won't work correctly. Then we use a small brass or aluminum tube with the OD of 3/16. This is glued into the nose of the blank, and provides the seat for the wings you mention. I don't have the specific length of this brass part written down. But I will on the next one I make. In fact on the 1st one I did, it was too long. I just used the 3/16 drill & took a little of the brass after it was glue in till the mechanism worked.

We bought the brass & aluminum tubes from a local Hobby Town store. He used aluminum, but I thought brass would be a better choice. But since the pentel pencil basically uses the plastic from the pencil, I think aluminum will be more than adequate. If anything, the glue might be the weak link.

I hope this makes sense. If you want more info, or anything cleared up, just send me a PM, and I'll do my best to help.

Here's my 1st. I used an alumilite blank, but I'll make a wood version soon. I do need to figure out a different clip. I had to stretch this one too much since I didn't turn the body down as thin as the Pentel. Kinda ugly, but it's secure. The pencil isn't great as far as looks, but it does feel good, and works perfectly.
 

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Alex D

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I work at an engineering firm and have made a large number of these for my co-workers. FWIW, I use one of these step drills: Step Drills - The Perfect Collection


Note that he suggests drilling the bulk of the whole with a regular drill then using the step for the final part in order to keep the step drill sharp as long as possible.


It's really nice to be able to just swap in whatever size you want.


Cheers,
Alex
 

penicillin

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You can find Pentel P203 0.3 mm pencils from sources outside the USA.

You can find many other brands of 0.3 mm pencils online, and also at art supply stores, but I suspect that those stores are starting to disappear around the country.

I have a few Sanford ProTouch II 0.3 mm pencils from a long time ago, but they are no longer available. They are wonderful writing instruments, but very delicate. I am not sure, but they may be rare and valuable. I like them too much to mess with them. It feels almost like sacrilege. I am sharing a photo I borrowed from an eBay listing.

For this project, I will buy some Pentel P203 pencils, but not until I have perfected it with the less expensive, more easily obtained P205 pencil first.

Thanks again to everyone for their advice and help. It is nice to know that I am on the right track and have found new tools to help me on my quest.
 

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