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"CadillacPat's DieCast Customizing Tutorials, Drill Bit Collar"


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#1 CadillacPat

CadillacPat

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Posted 30 April 2012 - 01:31 PM

" Custom Drill Bit Collar Stop "

This Tutorial relates to my " Disassembly and Reassembly " Tutorial.
Instructions here deal with procedures after you have removed the base from the casting.
Here's a way to make a custom fit Drill Bit Collar to accurately control the depth your Drill Bit sinks into the Rivet post of your 1/64" Customs, when you are using the 1/16" bit or the 3/32" bit to tap the Rivet Post.

Since this Tutorial will discuss assembling your Customs with 3/32" rivets the tubing you will need is 1/8" Brass Tubing for slipping over a 3/32" Drill Bit.
Hobby and Hardware stores have small Copper, Aluminum and Brass tubing but Brass is the hardest making it more lasting for our purposes. If you can't find Brass then use Copper.

Here's the tools you'll need to tap your Rivet posts for Rivet reassembly.
Variable Speed Handdrill, 1/8" Brass Tubing ( I'm showing Aluminum Tubing in this picture because I'm out of Brass), Tubing Cutter or Razor Saw, Marker, File for fine tuning length of your Drill Bit Collar/Bit Stop.

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First,
Remove the Rivet Cap holding the Base on the Body (see Disassembly and Reassembly Tutorial) with a 3/16" Pilot Point bit.
I prefer a Variable Speed Handdrill since it only takes a few turns to peel off the mushroom cap of the Rivet.

You are now ready to make your Drill Bit Collar.
Seat your 3/32" Bit completely into the Chuck of your Drill.
Now, lay your 1/8" tubing alongside the exposed length of the bit and mark the tubing the same length as that portion of the bit protruding from the Chuck.

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Use either a small Tubing Cutter or a Razor Saw to make your cut.

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Twist the short length of tubing down over the exposed portion of the Drill Bit.
If necessary, file down the tubing so it is exactly the same length of the Bit.
Now, lay one of your 3/32" Rivets up next to the end of the Bit and mark the length of the Set End of the Rivet on the Tubing.

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Remove the Tubing from the Drill Bit, make your cut and twist the tubing back down onto the Bit.
Check for proper length by laying a Rivet up against the exposed end of the Drill Bit.

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That's all there is to it.
You're finished and your Drill Bit Collar/Bit Stop will keep you from drilling too far and going through the Trunk or Hood of your Customs to be.
As you've noticed I've made my marks the full length of the Set End of the replacement Rivet.
Most casting's Rivet Posts are long enough to allow drilling them out at this depth.
However, every now and then you will run into castings whose post's are short.
Take a look at the next picture.

You will see the Ball of the Rivet that pulls up into the sleeve which gives the Rivet it's strength.
The diameter of this Ball can actually be subtracted from the depth you need to drill into the Rivet post.
It doesn't look like a great deal of difference but trust me, it can make all the difference in the world

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So, for super short Rivet Posts keep this minute extra length (diameter of the ball) in mind when performing the steps of my Tutorial.
You can make your marks the length of the Set End of the Rivet minus the small Ball on the end.
Or, just back off a hair when drilling and don't allow the Drill Bit Collar to touch the Rivet post.

Note:
I check for correct depth (with one of the 3/32" Rivets) after tapping every one of my Rivet Posts whether I am drilling one casting for a single Customer or 1000 for a Convention or Event.
It's best to be sure before you begin painting.

I keep a small bottle cap of oil handy and dip the end of my bit into it before drilling each Rivet Post.
It keeps the drill bit from loading up with molten metal.

If you are using tiny sheet metal screws to reassemble your castings and are drilling 1/16" holes to do so, you can use 3/32" tubing for your Drill Bit Collar/Bit Stop on 1/16" drill bits.

Two final notes.
1) I never hold castings in the palm of my hand when drilling them.
I hold one end and lay the opposite end up against the edge of a wooden table.
You can further pad the edge of the table using a folded towel.
This keeps my hand at least two inches away from the drill bit and since I'm only using short light squeezes on the trigger of the Variable Speed Handdrill there is very, very little chance of an accident.
I choose to drill out all my castings by hand and find it is much faster and easier, and more accurate than using a Drill Press.

2) Remember to file or grind away the sharp enlarged edge surrounding your Rivet Post after you have tapped it.
See my " Disassembly and Reassembly " Tutorial.

Have a good time,
Your Drill Instructor,

CadillacPat

Edited by CadillacPat, 01 May 2012 - 03:34 PM.