Yea, I understand, Vincent. When carbide bits get that small, it's best to use a drill press and/or choke up on the bit with a pin vise - as Dave (hon30critter) recommended earlier - to minimize any flexing. That's why I don't care for the large (1/8") shanks on tiny bits. It's better to just chuck down on the actual diameter of the drill bit.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Tom,
I agree it does work quite well for larger bits. I use them quite a bit on automotive stuff. However, the original poster was asking about the #80 bits with the 1/8" shank, and that's what I was reffering to. I had bought a set of 50 of those those a few months ago and broke almost all of them on 1 stewart F-unit.
Vincent
Wants: 1. high-quality, sound equipped, SD40-2s, C636s, C30-7s, and F-units in BN. As for ones that don't cost an arm and a leg, that's out of the question....
2. An end to the limited-production and other crap that makes models harder to get and more expensive.
Packer Avoid carbide like the plague. It breaks if you look at it wrong...
Avoid carbide like the plague. It breaks if you look at it wrong...
Vincent,
Your above statement is somewhat misleading. Carbide is a wonderful material because it's hardness makes it cutting edge last longer than high-speed steel (HSS). As mentioned earlier, it's great in virtually any material and you can run it either wet (lubricated) or dry (non-lubricated). With plastic, however, it's generally best to run it wet to help dissipate heat so that the material doesn't melt onto the drill bit or end mill, or create a larger hole than you intended.
Carbide's weakness comes from it's strength in that it is more brittle than steel and less able to take perpendicular flexing. As long as you know it's characteristics, it will serve you well. Cost is another factor as carbide is more expensive than HSS.
I bought these ones and like them a lot. I've only broken 2, over the course of 5 stewart F-units.
http://www.amazon.com/High-speed-Euro-Twist-Drills-Size/dp/B005O144YS/ref=sr_1_9?ie=UTF8&qid=1345074715&sr=8-9&keywords=%2380+drill+bit+jewelry+tools
I agree with Jay. I haven't used a #80 bit in years to drill out for grabs. Besides being easier to install, it allows room for the CA and with a bit of wiggle room you can make some slight adjustments if need be.
The high speed steel bits are all that you would need. By chucking up in a pinvise, bending or breakage is reduced.
Modeling B&O- Chessie Bob K. www.ssmrc.org
Dave and Odie got it right on.
Do not use high speed on plastic. You just melt and clog the drill once the plastic cools and sets up. Chuck the drill in a very slow drill to just the depth of what you are drilling through. Stepped drills like for a Dremmel 1/8" shank down to #80 are itchin' to break with the slightest wrong lateral move. They are designed for tight ball bearing tolerance high speed drilling in a rigidly fixed mount where either the motor and shank or the work is precisely fed into the bit with zero lateral play throughout the entire operation. Only in this situation are carbide bits expected to pay off. 90% of the tiny carbide bits see precision, repetitive drilling application in drilling our fiberglass and phenolic circuit boards in CNC operations.
Still, I use the stepped drills, (carbide and steel) in both the handheld dremmel and in hand chuck pin vises and just accept the breakage which can be limited by careful operations. If you really are drilling hundreds of holes. You just have to mount the drill in a rigid press of sorts. The work will proceed rapidly and with almost zero breakage.
Richard
If I can't fix it, I can fix it so it can't be fixed
I quit using #79 & #80 bits years ago, it wasn't worth the agravation and expense once I realized that a #78 would do the job just fine (actually it makes it a lot easier to insert .010 wire grabs). When you insert a grab iron for exmple and add the CA from the rear, capillary action draws the CA in and fills the hole around the wire. After you touch up the grab with paint you can't tell what size hole it was.
For drilling a lot holes I use a 12vplt drill hooked up to an old MRC power pack. You don't get a lot of torque but it's plenty for plastic and with the controller you keep the rpms down so you won't melt the plastic and you won't get carpul tunnel syndrome. Harbor Freight and Micromark have had then for sale.
A trick someone taught me a long time ago; if you have to drill small holes in metal frames and such, drill a larger hole first, (#65 - 60ish), fill the hole with JB Qwik epoxy (best) or CA gel, let it harden, sand smooth, then redrill with the proper size and you'll have a lot less breakage if any.
Carbide bits are best used with lubrication in a drill press. I only use them to drill brass. I use the above process for any white metal and Zamac.(Zink).
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
I use carbide drill bits with a hand-held Dremel all the time to drill holes in metal, and have never broken one. As long as you don't twist them they will not break.
The only way you will make out using carbide is if you do it in a mini drill press...that takes some of the operator error out of the situation. I prefer to use a chuck in a low rpm mini battery drill to drill tiny holes. A dremel is far too fast, even at its slowest speed.
I have been using the solid carbide drills for a couple of years now, but only on plastics. I bought a set of reconditioned ones that are absolutely great on plastic; but, as has been mentioned they are brittle. Mine all have 1/8" shanks with a 1//4" plastic collar that makes them very easy to use without a pin vise. They are very easy to break and usually it happens when I move the collar just a little off perpendicular to the surface. I have gone back to HSS drills for some of the sizes that I ran out of (breaking). I am very carefull now but still like them. Mine came from Megatool, but the assorted set isn't available any longer. I paid $20 for a set of 48 bits (6 of each size). These were made for PC board drilling in automated machines.
-Bob
Life is what happens while you are making other plans!
There have been a few posts recently about #80 carbide bits with the larger shank and the general conclusion was that they do not stand up well with hand drilling. They are more suited for use with a drill press.
My suggestion for hand drilling is to use the cheaper steel bits, but when you chuck them put them far enough into the chuck that there is only enough of the bit showing to drill through the thickness of the plastic you are working with. That runs contrary to most drilling practise but by chucking the bits short you eliminate the tendancy for the bits to flex, and the sideways pressure applied to the bits when they are bent is what breaks them.
Try it. It has worked for me and since I started to use this method I have not had to buy any more bits.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
cowman If you are just drilling into plastic, I would think that steel would do fine. Never have used a tiny carbide bit, but would think they would be better for metal. Thinking of brass, it is soft and if the carbide ones are prone to breaking, you might be better off with a pack of less expensive drills.
If you are just drilling into plastic, I would think that steel would do fine. Never have used a tiny carbide bit, but would think they would be better for metal. Thinking of brass, it is soft and if the carbide ones are prone to breaking, you might be better off with a pack of less expensive drills.
Actually, Richard, carbide works on both plastic and metal quite well. The plus to carbide is that you can run it either "dry" (using no lubricant) or "wet" (with lubricant). For plastic @ high speed, you should always use lubricant. With metal you can go either way.
Carbide is a hard material and lasts much longer than high speed steel but, consequently, it's also a brittle material. (That's the trade-off.) Quick temperature changes or perpendicular stress will fracture carbide. If a carbide bit hits a hard floor (e.g. concrete) just right, it will actually shatter.
As mentioned, carbide is overkill for hand drilling into styrene and will get fairly expensive as the drill bits get smaller in OD. With that said, "coated" bits (e.g. w/ titanium nitride) might be worth the investment, as you should need to purchase fewer of them.
Avoid the carbide steel bits. They break if you give them a dirty look! Find the regular steel bits. That's what I use.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
Kato,
If you are really going to drill out that many grab iron holes, I would just buy a couple of dozen of the less expensive steel drill bits from a machining supply business. Yes, carbide is hard and durable...but it is also brittle and doesn't take stress well - i.e. bending and torquing. Carbide is also overkill for the styrene and each one will be fairly expensive that small. (At least $10/pc)
Also, just buy the ones that have the identical shaft OD as the drill bit itself and use a pin vise to drill them out by hand. You get a better "feel" for how the drill bit is cutting, there's less chance of "melting" the styrene, and you'll break less bits overall.
And you may want to consider using a #78 drill bit (instead of the #80) to "oversize" your grab iron holes slightly. It's only 2.5 mil (0.0025") larger in OD than the #80 but it will 1) make it easier to insert the grab iron into the hole, and 2) allow for any adhesive expansion.
Just my ...
Just my thoughts.
Good luck,
I need to drill a couple thousand holes with a #80 drill bit for grab irons. I saw some on ebay that are carbide with the 1/8" shank, but with warnings that they are more brittle than the regular steel bits. Has anybody used the carbide bits and are they so brittle that I would be better off just using the regular steel? Or are they the best way to go? Just be a little more careful. Thanks in advance to anybody who has had experience using both and would like to answer.