how do I scribe 'notches' and very small circles?

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pawces
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how do I scribe 'notches' and very small circles?

Post by pawces »

How do I go about scribing notches that are wider than the scribing tool's blade? See the head in the example below (the detailed one on the left). Notice how in certain sections of a scribed line, there is a notch that goes off in a perpendicular direction (theres a parallel one in the mohawk too) , and it is wider than a regular scribed line.

http://blog-imgs-54-origin.fc2.com/s/h/ ... 728601.jpg

Is this done with a special tool? The notches do not appear to be the same shape...

Also, I'd like to scribe really small circles, such that I can fit small plastic tubes snugly over them? A compass won't work as the diameter is too big, I want the diameter to go as small as those on plastic straws/lollipop sticks.

thanks in advance!

*image is borrowed from SHUNNEIGE, all copyrights belong to him.
Last edited by pawces on Mon Apr 29, 2013 12:39 am, edited 1 time in total.
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photoguy
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Post by photoguy »

A chisel of some sort would probably be perfect for your wide lines. (Can't see the picture, but understand the description). Should be available at your art supply store that carries wood working / doll house tools - or Micromart.

You can also find circular hole saws in various sizes for hobbyists. If there is a specific size you need, you can pick up a piece of brass stock at the hobby shop. cut off a couple inch length, and use a round needle file to sharpen the end. Then use a triangular file to cut a couple of fine teeth into the sharpened edge. Spinning the tool between your fingers, or chucked into a pin vise, will produce very consistent, perfectly round holes in plastic or balsa.
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pawces
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Post by pawces »

Not sure why you can't see the picture, but I added a link below it just in case.

I thought it might have been carved out. I'm based in the Philippines and I have a tough time finding the right tools for the job, but I'm always open to making my own. Off the bat what comes to mind is a mini screwdriver...maybe I can sharpen it enough to work with plastic :P Brass rods may be a bit tougher to find, but I get the idea. Thanks! :8)
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Post by Kylwell »

http://blog-imgs-54-origin.fc2.com/s/h/ ... 6539da.jpg

Get a fine metal file, a sharpening stone (for knifes) and a steel nail. Cut the head off the nail and chuck it into a drill to make a basic lathe. Use the file to sharpen the nail to a point then file a flat into it the width of the notch you need. Takes some time but can be done.
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Post by Tankmodeler »

pawces wrote:Not sure why you can't see the picture, but I added a link below it just in case. )
As a new member, you should read the forum rules. :) One of the first rules is that you are not allowed to post images directly in the forum, only _links_ to images.

Now, you did that except the link goes to a 404 not found error in some text format or language my machine doesn't uderstand at all.

Please recheck that link address 'cause I'd like to see the problem. :)

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Kylwell
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Post by Kylwell »

Unfortunately they have a image sharing block.

Here's the referring page http://shunneige.blog.fc2.com/blog-category-12.html
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Post by Jestermon »

Man I got to figure out how to do that myself.
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Post by Umi_Ryuzuki »

I would say, very fine cuts and chisel work, or a back scraper.
Dental tools come to mind. I have custom filed a few myself.

Excellent before and after pics on that page.
Thanks for finding the base page Kywell.

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Post by pawces »

Tankmodeler wrote:
pawces wrote:Not sure why you can't see the picture, but I added a link below it just in case. )
As a new member, you should read the forum rules. :) One of the first rules is that you are not allowed to post images directly in the forum, only _links_ to images.

Now, you did that except the link goes to a 404 not found error in some text format or language my machine doesn't uderstand at all.

Please recheck that link address 'cause I'd like to see the problem. :)

Paul
Sorry, totally spaced on that one :shock: , I've been on a lot of forums and this is the first one that doesn't allow direct image posting. I'll know better next time. Anyway, thanks for all the ideas on how to possibly go about this, i'll be crafting my own special tool this weekend.
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Post by Glorfindel »

pawces to answer the "small circles" enigma get your self some circle scribing templates. There are so many out in the market so try Staples or Office Max for starters. They'll have them in the drafting department and also have sets of squares, rectangles, ovals, and odd shapes all of various sizes. Hasagawa makes some great templates as does Verlinden. You can score these at your local hobby shop. The circles also come in many different sizes. So when you've located the circle in scale that's good for you try and tape the template in to place and/or hold it down firmly. Your scribing tool for this will be a pin with a sharp tip. Make extremely light circles as if your lightly scetching the lines in by pencil using little to no pressure at all. Let the tip drag across the surface of the plastic and continue to trace the inside dimension of the template. After several circular motions you will notice the plastic starting to lightly scratch and flake up. Don't stop. Keep making circles and don't move the template!! You can blow off the dust to see roughly how deep you've scribed and continue if you need to go deeper. When done a light sanding will smoothen out any ridges left from the pin. Remember when scribing....pin for circles, blade for lines. (well in most cases anyway) Hope this helps.
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Post by Mark Yungblut »

If I am looking for extreme precision with a template I put small sections of double sided tape on the side facing the plastic. This will keep the template from moving when you scribe. I do the same on a ruler when I scribe straight lines. For curved lines I'd invest in a set of French curves.
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Post by Glorfindel »

pawces, Mark has a great idea there with double sided tape. That's an excellent tip that should work wonders.
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Post by naoto »

Glorfindel wrote:There are so many out in the market so try Staples or Office Max for starters. They'll have them in the drafting department and also have sets of squares, rectangles, ovals, and odd shapes all of various sizes. Hasagawa makes some great templates as does Verlinden.
Ah yes... speaking of a typical drafting tool - erasing shield - that was frequently "repurposed" by modelers back during the time before special-made scribing templates became available.

Another commonly "repurposed" item -- Dymo tape.
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