Drill Templates?

[Dunc1]

Ian Bradley, in his book The Amateur's Workshop (ISBN 1-85486-130-1) notes that while accurate layout is easy, maintaining that accuracy when actually drilling the hole is another story. He details how to use toolmaker's buttons to get the hole "spot on." This idea is very old; likely lost to many of us newbies.

 

[Lew Hartswick]

He details how to use toolmaker's buttons to get the hole "spot on.".

I haven't seen these "toolmakers buttons" so in what way are they any more "spot on"
than a DRO on a mill ?
...lew...

 

[aonemarine]

Ive been having some issues drilling small accurate holes as well. I think i have broken about 5 #43 drill bits so far this week trying to sort things out. Ive been drilling on my bridgeport and had figured out a few things with my drill chuck not running true and a couple other things and thought I had it licked. drilling some brass today making connecting rods for my first project I snapped off another bit. Funny thing was that I had pre drilled with a 1/16" bit first with no problems, this had me scratching my head as to what was going on. I then decided to try drilling more 1/16" holes, 20 holes later and no problems, I even started using the power down feed at .001" per rev. another 20 holes and no problems. Great I thought, then tried another #43 drill... SNAP ok very annoyed at this point, grabed the last of the #43 drills from the store and tried to drill it by spinning the quil by hand slowly. I know what the problem is now, the drill bit is getting such a bite that is actually binds up and breaks off, a little bit of reworking on the drill bit and I can now drill a #43 hole. You have no Idea how crazy this was making me trying to figure out what was going on and blaming my old clunky mill for the problem.
I also made a small fixture for holding the rod that has bushings in it to help locate the holes in the rod cap and will also position the rod so I can drill it for the rod journal and wrist pin. It was a bit of work but figured it would save time in the long run.

 

[Dunc1]

I don't expect that they would exceed the accuracy of a dro. They came along long before. I have not used them myself. but posted this more as "lost to history."

 

[MachineTom]

I can't see why you drilled the 1/16 hole to begin with, Spot the location with a spotting drill, then right through with a #43. The difference between the two drills is only .0165.

You would likely have similar result if you drill a 7/16 hole then used a 1/2 drill, it would not be easy to do in any metal, but Brass, urg!

 

[Tonnetto]

There's a good trick for drilling brass with any size drill, the cutting edge should have a neutral rake. On small drills just take a fine stone and run it against the cutting edge holding the stone parallel with the axis of the drill but angled so you make contact with the entire cutting edge. A few strokes should make a small land on the cutting edge. Same with larger drills except I find it easier to carefully "nudge" the cutting edge against the side of a bench grinding wheel, just a very small amount is necessary and make sure to do both cutting edges evenly. A drill modified in this manner will cut brass like butter. I can post a couple pics if anybody's interested.

 

[aonemarine]

IM interested!!

So your saying that the breakage is more than likely caused by the fact that I pre drilled with the 1/16" drill bit??? that and the rake of the drill bit?? Is brass notorious for this problem? Yea Im a bit of a nube in this area....

 

[aonemarine]

I did manage to get my rods drilled and tapped, drilled and reamed one but started getting tired and packed it up until tomorrow...

 

[jack620]

Tonnetto,
I guess, having modified the bit to cut brass, it is no longer of any use for cutting steel? Do you have a set of "brass only" drill bits, or do you re-sharpen them after using them on brass?
Chris

 

[Woodster]

Drills altered in this way will still cut steel, but need more pressure. Drill "Grab" is common when double drilling, especially in brass and reducing the rake to 0 will alleviate this. Other drill modifications are useful too! Like backing off a drill for use in plastic to prevent grabbing, web thinning to reduce lobe formation, even stoning the corner to improve surface finish.

 

[aonemarine]

Well I have plenty of bits I can practice on regrinding is there any picturees or tutorials on the web you know of for grinding a bit for brass?? Guess I can just experiment a bit and see how things go, what do I have to loose except re breaking a broken bit...

 

[aonemarine]

OK zero rake works like a champ, but my drill bit sharpening ability needs some work to get the tip true. Using a marker and a diamond file I got it close but not perfect...

 

[robcas631]

I Should have asked a more thorough question. I am looking for a template that will divide circles into equal parts. Five, six even seven parts.

 

[robcas631]

This is it.

http://ceramicartsdaily.org/wp-content/uploads/2010/06/dividingweb31.jpg

 

[robcas631]

The measure of skill is drilling from one side of a piece, then the other and having them meet up perfectly.

 

[gus]

The measure of skill is drilling from one side of a piece, then the other and having them meet up perfectly.

Hi Rob,

I had an elderly precision fitter/tool maker. Every time he completed a 12 ft
Shell & Tube Heat Exchanger Tube Nest,I could see a smile on his face. He made the tube sheet drilling jig.The holes on tube sheet were so close to each other and any slight run-out would show up but his was just perfect.
His Jobbers Drill Set is private and personal and off limit to everybody including me the Ops Manager. However he taught me to grind drill bits with the point relief on a weekend. He also ground a set of Dormers Drill for me.
His drill bits cuts on both sides.A true blue blood Master Tradesman.
He is another master at cutting gear tooth on the shaper with minimum filing
touch up.


Sorry.I did not have too much time for this master fitter. Gus spent too much time chasing figures for the USA Corporate Bosses. However would buy him good coffee and give the Ingersoll-Rand Year end gifts such as pens,golf caps
and cheapy watches with IR logo when I dropped by.

Wished he is still around to teach me marking,scribing,punching and dead centre drilling.


Gus Teng.

 

[chrsbrbnk]

If you need fair hole location use a center drill to spot the hole, it helps a bunch. If you drill the hole from both sides to meet in the middle they will never meet perfect maybe close but there is always some mismatch. but it can give better location than drilling all the way thru a thick part , consider drilling from both sides with say a 1/64 under than come back and run an onsize drill all the way thru from one side. ( drill reaming) our cnc guys on some tiny hole stuff will only drill on surfaces that have been surface ground smooth 32- 16 rms or so. another trick that works is making a very concentric hard pointed rod with the same angle as the drill point then use it as a center punch in the quill making tiny center punch marks for starting the drill used when the drill is smaller than the center drill tip say like .015 or smaller . feed and speeds all matter here some crap can really work harden. All this relates to whatever following uses of holes like reaming and tapping, an amazing number of tapping problems come back to drilled hole conditions. alotta guys use a coolant

 

[robcas631]

Chrs ty for the advise.

 

[robcas631]

Gus, Grinding bits is a talent and must for creating an accurate hole. No one likes drifting....How did you sharpen bit's .125" and less? ~ Rob

 

[gus]

Gus, Grinding bits is a talent and must for creating an accurate hole. No one likes drifting....How did you sharpen bit's .125" and less? ~ Rob

Hi Rob,

I can manage to grind 3/16 onwards but 1/8 would be tough for a 70 year young man. Have not tried using magnifying glass to help grind 1/8 and below.


Gus Teng