maker of small drill bits (#78, #80) for hand drilling resin kits


Dennis Storzek <dennis@...>
 

On Wed, Jul 13, 2022 at 09:00 AM, hockenheim68 wrote:
I've used guitar string forever. Cut as described above but also sometimes hammered and stoned to make a spear point if using larger diameter strings.
For reference here is a pic of a spear point used for drilling glass:


This is a carbide tipped tool, the tip is wider than the shank, but doesn't have to be. Also, for use in plastic and resin the elliptical curves aren't needed, as Andrew says, just flatten the end of the steel wire and stone angles to a point.

Dennis Storzek


Fred Swanson
 

I used to get guitar strings free from the music store.  Anytime I went there I'd find drops of strings on the floor from where they changed strings, a lot of it.  Some would look at me funny but most of the time they were more than happy I was picking the stuff up. I would tell them it's for a project.
Fred Swanson


Ralph W. Brown
 

Hi Dave,
 
I wasn’t sure of the spelling either, but I know about them nonetheless.  The typically used by sign painters and other artists, and I recall a photo of a painter using one to letter a PRR passenger car.  I just hadn’t thought of using one drilling holes or applying glue or decals.  Great idea though.
 
Ralph Brown
Portland, Maine
PRRT&HS No. 3966
NMRA No. L2532

rbrown51[at]maine[dot]rr[dot]com
 
From: Dave Parker via groups.io
Sent: Wednesday, July 13, 2022 12:15 PM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] maker of small drill bits (#78, #80) for hand drilling resin kits
 
On Wed, Jul 13, 2022 at 09:00 AM, hockenheim68 wrote:
Are folks with the shakes using maul sticks when working? Isolating and stabilizing your hands can make a big difference.
I had to Google this one, and it's spelled mahl stick (not maul).  Very cool idea that I had never heard of.  Andrew, thanks for the tip.
 
--
Dave Parker
Swall Meadows, CA


Dave Parker
 

On Wed, Jul 13, 2022 at 09:00 AM, hockenheim68 wrote:
Are folks with the shakes using maul sticks when working? Isolating and stabilizing your hands can make a big difference.
I had to Google this one, and it's spelled mahl stick (not maul).  Very cool idea that I had never heard of.  Andrew, thanks for the tip.
 
--
Dave Parker
Swall Meadows, CA


hockenheim68
 

I've used guitar string forever. Cut as described above but also sometimes hammered and stoned to make a spear point if using larger diameter strings. Started out using fine pins but the string/burr drills worked better. The smallest easily available strings are .007" and they work well with .004" grabs. Done the same for simulated NBWs. They flex and cost literal pennies. They're also very, very sharp, so be careful. I mount mine in Excel knife handles. The collets are soft enough to hold them for a time. Eventually they stop holding and the string drill needs to be kinked and flattened slightly to give the collet something to bite.

For handwork larger than No.80 there's a couple of Huot indexes and for the money I think they've stood up well. They break but really only when dropped. Paid $30 and $5 respectively but even at $60+ I think they're good drills. For perspective a single micro cutter from Harvey or MA Ford can run that.

PS Are folks with the shakes using maul sticks when working? Isolating and stabilizing your hands can make a big difference.

Andrew Hutchinson


Dennis Storzek <dennis@...>
 

On Tue, Jul 12, 2022 at 10:32 AM, Philip Dove wrote:
At an Nmra convention in Kansas City l attended a clinic on building structures and the person used hypodermic needles for making small holes. The method works in thin plastics and card but the holes are too big for grabs in 3.5 mm scale. 
Actually, the method I described, stoning a diagonal flat on the shank of a broken drill mimics the shape of a hypodermic needle without the hole. It drills soft materials OK, but takes a lot of turns due to cutting via scraping, which is why I suggested driving it in a speed controlled motor tool.

Dennis Storzek


Philip Dove
 

At an Nmra convention in Kansas City l attended a clinic on building structures and the person used hypodermic needles for making small holes. The method works in thin plastics and card but the holes are too big for grabs in 3.5 mm scale. 


Dennis Storzek <dennis@...>
 

On Mon, Jul 11, 2022 at 04:14 PM, Dave Parker wrote:
I can't remember if I even tried this with PB wire, but I feel it's too soft.  But a steel guitar string?  You bet.  I generally don't even dress the the tip with a stone.  Cutting it with pair of small dikes makes a working tip.  Just need to keep the exposed part to the wire to a minimum.

And yes, slow.  Santa brought me the slowest speed Foredom tool a couple of Christmases back.  This setup works great in resin (and wood), and acceptably in styrene.  I do a lot with 0.008" grabs, so 0.010" wire is a good choice for the drill.
I donno, Tichy's PB wire is pretty hard, much harder than the DA brass wire. I figured I'd suggest it since it could also be used to make the replacement grabs. But I see guitar strings are available in all the diameters a modeler could need, .008, .010. .012, and .013, so likely a better choice for drilling holes. The best part of not having flutes is there is more material in the drill shank, almost twice as much.

Dennis Storzek


Dave Parker
 

On Mon, Jul 11, 2022 at 01:28 PM, Dennis Storzek wrote:
I wonder if a piece of phosphor bronze wire, like Tichy sells, would work, sharpened like this and driven at slow speed by a battery motor tool? They would certainly be cheap enough.
I can't remember if I even tried this with PB wire, but I feel it's too soft.  But a steel guitar string?  You bet.  I generally don't even dress the the tip with a stone.  Cutting it with pair of small dikes makes a working tip.  Just need to keep the exposed part to the wire to a minimum.

And yes, slow.  Santa brought me the slowest speed Foredom tool a couple of Christmases back.  This setup works great in resin (and wood), and acceptably in styrene.  I do a lot with 0.008" grabs, so 0.010" wire is a good choice for the drill.
 
--
Dave Parker
Swall Meadows, CA


Dennis Storzek <dennis@...>
 

On Mon, Jul 11, 2022 at 09:09 AM, Owen Thorne - owen at udel.edu wrote:
So, while choosing high-speed bits for hand-drilling plastic and resin seems counterintuitive, the commonly available carbide bits are specifically NOT recommended, as per above. Does anyone have experience with cobalt or carbon-tipped bits? Or is there another material, tip shape, angle, or coating we should be using for resin or plastic?
Most of the information you quoted is aimed at users who use the drills in machine tools. The material is typically chosen for its wear characteristics... But modelers don't wear drills out, they break them because they cannot keep them lined up with the portion that is buried in the work, which snaps the drill off. Remember, twist drills (the proper name for what you are calling "bits") unlike end mills, are not intended to cut on the side of the tool, so whatever direction the drill starts cutting, the tool has to be held in line, not allowed to bend. This would indicate that the toughest, most flexible drill would have the best chances of survival, and that would be high speed steel. Cobalt steel would be right up there also, but I doubt you will ever find that material in the sizes we modelers need. Solid tungsten carbide (carbide for short) is the exact opposite; extremely hard, but also exceedingly brittle. Carbide tipped drills aren't made in the small sizes, that is indeed a strategy to get hard cutting edges on a tough drill, but there is no commercial need in the sizes we use.

There seems to be a bit of confusion about carbide vs. carbon. Carbide is, as I said, short for tungsten carbide. Carbon is short for high carbon steel, which drills USED to be made of before high speed steel was developed decades ago. Some of the cheap import drills are still high carbon steel. Why? Because it's cheap, its basically high speed steel without all the alloy elements that give HSS its toughness. If you are snapping off drills all the time, they are likely high carbon steel.

As to grind (tip shape) years ago, when I still had eyesight and steady hands, I used to be able to resharpen hobby drills under magnification with a fine stone. In fact, when I snapped all the flutes off the drill, I found I could make an 'emergency' drill by stoning the remaining round rod off at a flat angle, so the result was a flat ovaloid face. These took a LOT more turning, but did get the job done. I wonder if a piece of phosphor bronze wire, like Tichy sells, would work, sharpened like this and driven at slow speed by a battery motor tool? They would certainly be cheap enough.

Dennis Storzek


Hudson Leighton
 

I would go with High Speed Steel.

Most commercial users of drills want a drill that will last in production machines.

That is what carbide and Cobalt drills are for.

But modelers are going to break / bend HSS drills long before they get dull.

I have done millions and millions of small holes in circuit boards, but using a huge CNC mills.

-Hudson


Owen Thorne - owen at udel.edu
 

I have enjoyed this discussion, but one question remains unanswered for me. I too have had trouble finding reliable affordable bits for hand-drilling plastic and resin and I remain unsure if I should be shopping for high-speed, carbide-tipped, carbon or another. For me, skinny bits from the hobby shop or Amazon suppliers break too easily and are often dull from the start. These bits rarely last long enough to dull, maybe because I am increasingly fumble-fingered and visually challenged with age but maybe because I am choosing the wrong drill-bit material. The expensive Otto Frei and Gesswein products RJ Dial discussed above are "high-speed" so is this the correct material to choose or are those just better quality (and pricier?)

I agree with folks who like the style of bit that has a 1/8th inch shaft and necks down to the bit. The collar with size info is convenient. Chucking them in and out, and sizing or keeping track of loose bits is so easy. Drill Bit City bits have been pretty good lately, but they still break for me, and they are more expensive to replace.

McMaster-Carr has provided me excellent tools and materials in the past, so I trust them. They write about bit materials here: https://www.mcmaster.com/drill-bits/

Quoting from their site:


"A number of factors determine which drill bit will be best for an application, including the type of material to be drilled, drilling speed, and desired number of holes per bit. Select a drill bit with the combination of material, finish, length, and style that will be best-suited for your job.


“Material

  • High-speed steel bits are for general purpose drilling in most material.
  • Cobalt steel bits have better heat and wear resistance than high-speed steel bits, so they can run up to 25% faster and have a longer tool life.
  • Carbide-tipped bits are more wear resistant than high-speed steel and cobalt steel bits, so they maintain their sharp edges longer for excellent performance on abrasive material, such as plastic. Because they aren't as brittle as solid carbide bits, they can be used in less rigid setups, such as a hand-held drill.
  • Carbide bits are harder, stronger, and more wear resistant than high-speed steel, cobalt steel, and carbide-tipped bits for the highest accuracy and longest tool life. They retain a sharp, hard edge at high temperatures for the best performance on hard and abrasive material. Made of solid carbide, these bits require rigid toolholding to prevent breakage and should not be used in hand-held drilling applications."

So, while choosing high-speed bits for hand-drilling plastic and resin seems counterintuitive, the commonly available carbide bits are specifically NOT recommended, as per above. Does anyone have experience with cobalt or carbon-tipped bits? Or is there another material, tip shape, angle, or coating we should be using for resin or plastic?

p.s. One key for me is lubrication, as Curt Fortenberry mentions above. I keep a hunk of beeswax on the bench and poke the bit into it each time I start a hole or clear the chips. And as Hudson suggests above, chucking the skinny bits really short also helps prevent breakage while using a smaller, finer pin vise has helped me to avoid lateral stresses that can break a bit.

Thank you, all,

--
T. Owen Thorne
Cecil County MD USA
owen at udel dot edu


Chuck Cover
 

Thanks to everyone who has responded.  It has been a big help.

 

Chuck Cover

Santa Fe, NM


Philip Dove
 

Yes l would have to agree the carbide bits are very brittle. Another modeller was surprised l'd managed to drill any holes without breaking them. 


ed_mines
 

I've been using these carbide bits but when I bought them from e bay a few years ago they were much less expensive. They are brittle as h... and if they break off you better drill another hole.


Ken Adams
 

My recent experience with the Gyros #78 drill bits I bought through Amazon was not good. They broke on the second hole I drilled with each bit. Earlier purchases of Gyros drill bits were ok as they would last 15-20 uses.  Even buying a recommended Starrett pin vise did not help.  It works much better with some older #78 Gyros I had on hand.

I used to buy from Otto Frei (ouch that rhymes) before the Pandemic as they are local in Oakland and I could order and they drop by for pickup avoiding shipping costs.  The drill bits were fairly long lasting.  

The thicker shaft on the GMAUVAIS bits at MSC looks like a possible solution to constant breakage.  I will put together an order in the near future for 10 packs of 77/78/79 bits and see if shipping is not prohibitive. 
--
Ken Adams
Omicron BA2.2 may come and go but I still live mostly in splendid Shelter In Place solitude
Location: About half way up Walnut Creek
Owner PlasticFreightCarBuilders@groups.io


Philip Dove
 

To get the right size drill for a task such as installing grab irons l first look on the packet for recommendations as to what size to use. I visually compare the two then drill a hole in scrap material and see if it works. Slightly oversize holes help as others said. For grab irons l drill right through the piece glue from the reverse and if neccessary then cut and file the reverse side of grab off if it's going to get in the way. 
To ensure the grabs are all protruding a uniform amount l put a small sliver of some unglueable plastic under the grab so they don't go in too far. I use resharpend Carbide drills because they are the only drills l have in US sizes. I don't drill unless l a relaxed and fresh because l use a pin vice, and breakages are three times as high if l'm tired or tense. 


Rick Jesionowski
 


Bruce Smith
 

Folks,

 

I also keep a digital caliper on my bench to check the size of wire, etched parts, or other parts, so I know which drill to select. As you note, a little wiggle room can help.

 

Regards,

Bruce

Bruce Smith

Auburn, AL

 

From: <main@RealSTMFC.groups.io> on behalf of Dennis Storzek <dennis@...>
Reply-To: "main@RealSTMFC.groups.io" <main@RealSTMFC.groups.io>
Date: Thursday, July 7, 2022 at 11:58 AM
To: "main@RealSTMFC.groups.io" <main@RealSTMFC.groups.io>
Subject: [EXT] Re: [RealSTMFC] maker of small drill bits (#78, #80) for hand drilling resin kits

 

CAUTION: Email Originated Outside of Auburn.

On Thu, Jul 7, 2022 at 09:17 AM, Kevin Macomber wrote:

How do you match up with the item to be inserted as it is so small.  My knowledge of these sizes of drill bits is low and appreciate the assistance

Google "number drill size chart". That will give you the size of number drills in thousandths of an inch, which is the same units of measure used by most hobby wire suppliers. Most pre-forrmed HO grab irons are .012" diameter wire, so a #80 drill at .0135" is just right, leaving some room for glue to surround the wire.

Dennis Storzek


Nelson Moyer
 

Here’s my bit size information.

 

Nelson Moyer

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Kevin Macomber
Sent: Thursday, July 7, 2022 11:18 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] maker of small drill bits (#78, #80) for hand drilling resin kits

 

What sizes are generally required.  How do you match up with the item to be inserted as it is so small.  My knowledge of these sizes of drill bits is low and appreciate the assistance.  Kevin