Carbide drill bits of 0.7-1.2mm size are priced at ~US$10 each at Digikey and Farnell while they are offered for a fraction of that at ebay.com, typically ~$1-1.50 per piece in a set. Does anyone know what these cheaper offerings from eBay are like for drilling FR4 boards?
Don't know, but I've had spotty results (used to be uniformly dismal) with Chinese cutting tools.
Digikey isn't really the best place to buy that sort of thing- KBC has M.A. Ford (made in USA) carbide 1/8" shank drills for $4.10 ea., which is not bad for a few pieces. McMaster wants about $4.50 each, but I don't think they ship to India.
This guy claims to have Kyocera bits at a very reasonable price (havn't tried him)
formatting link
Best regards, Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Without a serious Excelon type drill (zillion RPM air bearings, feed rate control, entry media) carbides tend to break. For home-drilled boards, use cheap steel drills and toss them when they get dull.
--
John Larkin, President Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com
Bad idea. An HSS drill is dull after about 10 holes of FR4. Even for hobby purposes you need carbide drill for FR4. I never had problems with carbide drills breaking unless I drilled in the aluminum base of my drill-press.
--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
I've had few to no problems*. You want to run them as fast spindle speed as possible. They cut FR4 like butta. I don't often drill much less than 0.8mm (0.031"), which is pretty sturdy- if you're trying to drill 0.015" holes, things might be dicier.
A few weeks ago I reached into one of the ubiquitous little boxes of resharpened carbide bits by mistake and about 8mm of tiny via-size bit punctured my finger and broke off in the finger. Ouch. This was after breaking a 1/4-20 tap off in a part, so I was grumpy to start with (took a couple hours to salvage the part). I thought a cheap "set of taps" would be okay at that huge size- I was wrong- bought some good quality ones (Chinese, but top-notch stuff) and no more problems. The cheap-a** 4-40 die wouldn't even thread onto a proper sized brass turning. Criminally bad "tool shaped" garbage- ultra brittle, dull, and not the right dimensions.
"Spehro Pefhany" wrote in message news: snipped-for-privacy@4ax.com...
Hmm... I suspect that some or most of those cheap bits at ebay are Chinese products.
It wouldn't make much difference for me even if they did ship to India because import hassles are a real PITA and well nigh insurmountable for those of us in remote parts of the country. But things have started looking up a bit recently in that respect. There are now at least a couple of Indian companies who offer to import just about anything from the US for a client. Their minimum shipping charge is for 1lb.
The prices are comparable to those at ebay and are certainly better than at those other sources. At least the manufacturer's name is known. Do you know anything about the other brand mentioned there - Precision Carbide? Unless someone comes along with a more attractive suggestion - not necessarily a lower price - I think I'll make a trial order for a ten-pack each of 2 or 3 different sizes.
Another thing I'll have to deal with is the drill. The 10k rpm drill I now use came only with 0.8mm, 1mm and 2.3mm collets. Thanks for the helpful input.
McMaster will permanently cut them off if they know it's being exported. They really want to add to the US trade deficit- only existing large export customers are being supported.
AFAIK, everyone uses 1/8" (3.175mm) shank drills (same as a Dremel tool), so if you get one of those you'll be okay for just about anything. It helps to be able to change the bits quickly when all the shanks are identical. With collars you can get the length spot on too.
Yes, I've used the smaller sizes. Because the new-style drill press didn't work I used to run 0.012 bits by hand(*)--that's a pain. Nowdays I think I'd try the old Model 210.
(*) index finger pressing on top for a bearing, rotate with 2nd finger
thumb. I managed 2 to 4 holes per bit before breaking them. :-)
Disgusting. Good clean, sharp, quality tools are a joy. HSS-- maintaining full hardness at red heat--is amazing.
I snapped a carbide bit off in a workpiece a couple days ago--that's a pain. It was a larger diameter bit so I thought using the big drill press would be okay. It wasn''t.
I have the same except I drilled a 1/8" hole in the center of the table so using 0.035" carbide bits don't hit any of the aluminum - though I haven't drilled FR-4 in quite a while. The board houses are so cheap it isn't really worth doing at home.
Get used dental burs from your dentist, or buy them new if you can find them for a reasonable price. They work well in my (newer style) Dremel drill press - haven't broken one yet.
At a guess, they were just fine, when they were new. Carbide drills for circuit board manufacture are mainly not resharpened, but are discarded (sold as surplus) after a certain number of holes have been drilled. If you aren't doing plated-through holes, they're certainly good enough at end-of-life for another few thousand holes.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.