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Question about micro drill bit sizes.

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  • Member since
    November 2008
  • From: Crawfordsville, Indiana
Question about micro drill bit sizes.
Posted by Wabashwheels on Monday, November 29, 2010 3:46 PM

I've nearly used up a small package of micro bits that I've had for years.  I've looked around the internet and it seems that the popular sizes are #61 - #80.  I cannot get a good guess at the size of the #80 drill bit from any photos I've seen.  The size bit I'm hoping to find comes in handy when I'm making holes to pass wire through.  The best analogy  would be drilling a .50 caliber gun barrel in 1/48 scale.  Would that hole be considered #80 or its inches equivalent of .0135 ?  Thanks, Rick.

 

  • Member since
    October 2007
  • From: Louisville, KY
Posted by pordoi on Monday, November 29, 2010 4:04 PM

Wabashwheels

... sizes are #61 - #80.  I cannot get a good guess at the size of the #80 drill bit from any photos I've seen. 

 

Here is a conversion table that correlates drill bit number, mm and inches.

 

http://bobmay.astronomy.net/misc/drillchart.htm

 

Don

 

 

  • Member since
    December 2002
  • From: Bury St Edmunds, Suffolk, England
Posted by Bish on Monday, November 29, 2010 4:23 PM

The smallest drill bits i have found are 0.3 mm, i have found this fine for drilling 1/72nd gun barrels and 1/35 7.92 mm barrels, so i would imagine a 0.4mm would be fine for .50 cal in that scale.

I am a Norfolk man and i glory in being so

 

On the bench: Airfix 1/72nd Harrier GR.3/Fujimi 1/72nd Ju 87D-3

  • Member since
    November 2005
Posted by Anonymous on Monday, November 29, 2010 4:37 PM

???

  • Member since
    December 2003
  • From: Indiana
Posted by hkshooter on Monday, November 29, 2010 5:29 PM

I think the answer you are looking for is .264mm, not .4mm

A #80 drill is .342mm, still to big for 50cal (12.5mm) in 1/48th scale.

  • Member since
    August 2005
  • From: Sydney, Australia
Posted by Phil_H on Monday, November 29, 2010 6:00 PM

The smallest drill bits I've found are 0.2mm, which would give you a 9.6mm hole in 1/48 or 7mm in 1/35 or 14.4mm in 1/72.

A 0.3mm bit would give you the equivalent of 14.4mm in 1/48.

fox
  • Member since
    January 2007
  • From: Narvon, Pa.
Posted by fox on Monday, November 29, 2010 6:42 PM

Found this chart a while back when checking out tubing for gun barrels. It's only in inches but it might help you.

http://www.docstoc.com/docs/11038233/Scale-Gun-Barrel-Chart

Good luck.

Jim Captain

 Main WIP: 

   On the Bench: Artesania Latina  (aka) Artists in the Latrine 1/75 Bluenose II

I keep hitting "escape", but I'm still here.

  • Member since
    June 2008
  • From: Iowa
Posted by Hans von Hammer on Tuesday, November 30, 2010 1:59 PM

The best analogy  would be drilling a .50 caliber gun barrel in 1/48 scale.  Would that hole be considered #80 or its inches equivalent of .0135 ?

Worrying about the diameter of a scale .50 bore being accurate is one of the symptons of AMS, Pard...

Grab a new #11 blade and measure the bore with the Mk I Eyeball, I say... Toast

And stock up on #80 bits...

  • Member since
    November 2008
  • From: Crawfordsville, Indiana
Posted by Wabashwheels on Tuesday, November 30, 2010 2:21 PM

Sorry guys, although I tend to lean towards obsessive/compulsive, I only used the analogy of drilling a .50 cal barrel as an example.  I wanted to use a size of hole that everyone would recognize.  I use the tiny bit to drill out things like wiring runs and radial engine wiring harnesses.  By the way, where would be an easy source to purchase hypodermic tube for those little gun barrels?  Thanks for all the input. You guys are great.  Rick.

 

  • Member since
    June 2008
  • From: Iowa
Posted by Hans von Hammer on Tuesday, November 30, 2010 3:23 PM

I was just pullin' yer leg a bit, Wheels..Toast

If you have it, check the November issue of FSM in the Reader Tips section, page 56... There's an ingenious solution to the hypodermic tubing issue, submitted by a brilliant, yet humble modeler named Mike Thompson from Ames, Iowa, that has one taking the plastic-handled Q-tips and stretching them like sprue into gun barrels...

 

  • Member since
    November 2008
  • From: Crawfordsville, Indiana
Posted by Wabashwheels on Tuesday, November 30, 2010 3:41 PM

Hans, that Thompson guy seems like a sharp cookie.  I've been a little leery of open flames in the house since the 2006 incident with the cat...Meoooooooooooowwwwwwwwwww!!!!!!!!!!!!   Rick.

 

  • Member since
    June 2008
  • From: Iowa
Posted by Hans von Hammer on Tuesday, November 30, 2010 4:17 PM

Hans, that Thompson guy seems like a sharp cookie.

Yeah, although he's a bit of a curmudgeonly ol' coot,  with a penchant for yelling at the TV, his cats, and the occasional passing car...

I've been a little leery of open flames in the house since the 2006 incident with the cat...Meoooooooooooowwwwwwwwwww!!!!!!!!!!!!  

Ah yes... The infamous Cat-asstrophy... Well, there's always electric heat and boiling water...  And "Blisters on mt Fingers!!!"

fox
  • Member since
    January 2007
  • From: Narvon, Pa.
Posted by fox on Tuesday, November 30, 2010 6:15 PM

Rick --- Here's the link to the Hypodermic Tubing site.

http://www.smallparts.com/stainless-steel-hypodermic-round-tubing/dp/B003TFFC9M/ref=sr_1_1?sr=1-1&qid=1291161795

Search Stainless Steel 316 or 304 Hypodermic Round Tubing. There is a minimum order, but once you get started it builds up fast. The Tubing comes in 6 foot lengths too, so 1 of each size you need lasts forever. At one of our groups meetings, 1 guy had bought a supply not realizing each piece was 6 ft. long, so he cut them up and passed some around to the other members. Each size comes in plastic tubes that just happen to be very useful too.

Hope this is useful to you. Good Luck.

Jim Captain

 

 Main WIP: 

   On the Bench: Artesania Latina  (aka) Artists in the Latrine 1/75 Bluenose II

I keep hitting "escape", but I'm still here.

  • Member since
    August 2005
  • From: Sydney, Australia
Posted by Phil_H on Tuesday, November 30, 2010 6:47 PM

You can also get fine brass tubing, which may be easier to work with than the stainless steel hypo tube.

One example is Griffon Model, who makes tubing down to sizes like  0.3mm, 0.4mm, 0,5mm

  • Member since
    November 2008
  • From: Crawfordsville, Indiana
Posted by Wabashwheels on Tuesday, November 30, 2010 8:27 PM

Jim, Phil, thanks for the leads.  Rick

 

  • Member since
    January 2007
Posted by the doog on Wednesday, December 1, 2010 11:32 AM

Whatever size you decide upon, be careful, cuz those little buggers break with annoying frequency!

  • Member since
    March 2005
  • From: West Virginia, USA
Posted by mfsob on Monday, December 6, 2010 10:51 AM

Yeah, if you're annoyed at having to buy #80 or #75 drill bits in 5-packs, don't be. I typically go through at least 1-2 #80 bits on every ship or airplane model. That may or may not have anything to do with the fact that a lot of things like catwalk grilles, machine gun ventilation sleeves, etc., in scales too small to metion, get bored out in the name of "realism."

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