Drill a tapered hole in delrin?

Signed-In Members Don't See This Ad
randyrls

randyrls

Member
Joined
Feb 2, 2006
Messages
5,117
Location
Harrisburg, PA 17112
I want to drill a tapered hole in delrin the shape of a slimline nib. It is about 17 degrees included angle, but I can't seem to find a drill bit that would work for this task.

Does anyone have any suggestions???
 
Signed-In Members Don't See This Ad
Yes Curly; I am looking to match the angle of a slim line nib. It is 17° by my angle gauge.

I like the rotary burr idea. The angle works out to a bit more that 30°

I have been making slim lines for the troops, but pressing in the transmission takes a while. Press in transmission, put the ink fill in, check the extension on the ink fill, remove the ink fill and press in more, put the ink fill in, etc.... ARGH!

I have an idea for a way to press the transmission in one go and be done with it. This is going to be a proof of concept. If it works well, I will publish it (and then PSI will steal the idea)..... :mad:
 
Last edited:
You could take a spade bit and grind the sides to get the point you want and drill the plastic after you make a pilot hole. A file should work to sharpen the edge.
 
Pete; THat is a great idea! I've used it before to make tapered holes in wood, but didn't think of it for this application.... Hmmm I wonder what the angle on the tip of a spade bit is.... Off to the workshop!
 
probably doesn't need to be a full taper. It could be stepped.
 

Attachments

  • nib.jpg
    nib.jpg
    563.4 KB · Views: 220
What ever you do if you get a sloppy fit you can wrap the nib in teflon tape, coat the hole with epoxy and press the nib into the hole. Plumber's putty would also work.
 
Make a resin casting or a few of them. Dead on then. The way Mr Vic described is the way they recommend when pushing in those trannys. Make a mark on one and all should be the same. Make sure all your refills are of the same length. Jigs that is the key to all mechanical projects. Make a jig is half the fun.
 
Last edited:
Dancing a jig is the other half of the fun! :)

Make certain you DO NOT press directly on the refill in any way shape or form ... they literally aren't made to take the pressure.
 
Well, If I was gonna do it.....

I'd get a cheap drill bit of a diameter equal to the largest diameter in your taper.

Cut a small piece of ply, the same thickness as your bit, at the 17' angle you need. Say a 1" piece of jointed/squared stock on the miter gauge on your TS.

Glue both sides to another thin piece of stock, using the drill bit as a spacer. Then glue a top onto that.

Mount this jig onto your grinder, square to the wheel. Put the bit in a drill, and slide it through the opening, and grind the tip down to the angle you need.

You'll end up with a sharp point that won't last long, but a small pilot hole should help with the drilling.

EDIT: I got the angle wrong in the pic. It's showing a blunt tip, but turn it 90' and it'll work. It's just a visual aid anyways, not a schematic.
 

Attachments

  • 17jig.jpg
    17jig.jpg
    39.8 KB · Views: 240
Last edited:
Delrin is fairly soft. You could make a bit from from any metal rod. Taper the tip to the right angle. A file should work while spinning on the lathe. Then grind or file to a half circle cross section. Easy peasy drill bit. I have step bits made this way from drill rod and heat treated. Any steel and maybe brass would work with plastic.


Sent from my iPhone using Penturners.org mobile app
 
Would you be able to post a picture of one of your bits made this way, please?

More4dan said:
Delrin is fairly soft. You could make a bit from from any metal rod. Taper the tip to the right angle. A file should work while spinning on the lathe. Then grind or file to a half circle cross section. Easy peasy drill bit. I have step bits made this way from drill rod and heat treated. Any steel and maybe brass would work with plastic.
Click to expand...
 
I have for 20 plus years used a taper reamer sold in electronic stores it fitted exactly the tip of a Slimline ,no fuss just exact, when I go to press I lightly ream the barreltop of the pen and the tip and then the entry to the winder. I use a 1 ton press I find ideal for the purpose.

When slimlines were new all I could buy was a step drill that cleaned the tube, reamed the brass and faced the blank. I will look for some pics to illustrate.

Peter.
 
My 30 yr old Step Drill, the pics of the two blanks illustrate the reaming from the step drill and the small section is still a snug fit.

I face blanks on a 12 inch faceplate sander.

You already have a pic and the taper reamer I mentioned illustrated from Edward.

Always works for me.

Peter.
 

Attachments

  • DSCF0003.JPG
    DSCF0003.JPG
    84.2 KB · Views: 215
  • DSCF0014.JPG
    DSCF0014.JPG
    40.6 KB · Views: 238
  • DSCF0020.JPG
    DSCF0020.JPG
    95.3 KB · Views: 218
Last edited:
Thanks, Pete. I used to love P.S. back in those days but stopped reading it when I was going to uni before that article was printed.
That's a really useful thing to know how to do.
I wonder what sizes drill rod comes in.
And I wonder if a drill made like this will work in wood.

Curly said:
Here you go Mal. An old Popular Science magazine article from the days when it had useful information.
Click to expand...
 
Last edited:
I worked for and endmill manufacturer for a while and we made tapered endmills.
MSC tapered end mills.
http://tinyurl.com/hujcv82 (this is a legit tinyURL)
They are not inexpensive but the angles are precise to +/- 0.5 degrees and will cut all along the taper.
Mcmaster.com has a nice selection also.
 
Last edited:
magpens said:
Thanks, Pete. I used to love P.S. back in those days but stopped reading it when I was going to uni before that article was printed.
That's a really useful thing to know how to do.
I wonder what sizes drill rod comes in.
And I wonder if a drill made like this will work in wood.

Curly said:
Here you go Mal. An old Popular Science magazine article from the days when it had useful information.
Click to expand...
Click to expand...



Drill rod comes in almost every diameter drill bits are made. You can also get O1 or W1 rod that can be heat treated. I have a bit like this for drilling a two diameter hole with a flat shoulder for recessing screws and rivets in knife handles. It works in wood, acrylic, bone, and trustone. I would not use it for steel at brass. They make cheap step drills.


Sent from my iPhone using Penturners.org mobile app
 
Thanks everybody; I believe a "D" drill bit is what I will go with. I can grind both the taper and flat for the drill bit on the drill rod.

Thanks again everyone! I will post an article when my idea is finalized.
 
Here is a link to a 0 to 14mm reamer which looks to have a taper of the size needed. I have two of them at home that are similar but made by a different manufacturer. I will check the angle against a slimline when I get home this afternoon and will post the results when it is done.
 
I did the test and it appears to be a perfect fit. The reamer is 47.5 mm long and goes from 0 to 14mm in diameter. Also, if you get one of these please be careful. If you drop it on your foot or hand, you are going to wind up with a deep stab wound the point is as sharp as a needle.
 
Mr Vic said:
You could save the trouble and cut a piece of aluminum angle iron to math the length from a correctly pressed together pen. the length = tip of nib to back of transmission. Works like a charm until you get some odd length refills.
Click to expand...

Yes that has been a bit of an issue. It works most times, but it fails often enough that I don't gain any time by doing it that way.
 
You must log in or register to reply here.
Back
Top Bottom