Post By Mcgyver
sensitive drill attachments...
I need to drill several hundred small holes for number one and three screws. My drill press doesn't have much feel with these size bits although it does have the speed. I don't want to buy a sensitive drill, but I've noticed that both Royal and Albrecht market "sensitive drill attachments." These are basically telescoping shafts attached to a drill chuck with a freewheeling knurled disk that allow you to manually move the drill chuck down to the work when clamped in a drillpress/milling machine etc.
Are these any good? I'm drilling mostly brass and some steel.
Many thanks, Charles Morrill
I think several hundred holes would be uncomfortable with a sensitive chuck. I have a Royal. They work and have decent feel but they're not meant for that kind of volume. The knurled ring isn't as nice as a feed lever. Or, despite the cheezy construction, a Dremel drill press actually works pretty well. Rather than the head moving, the little 4-inch table moves up and down. It spins fast and it isn't tiring to use. I've done thousands of small holes (like number 70 or 80 carbide) in PC boards with a Dremel with minimal drill breakage.
Charles, as many will tell you high speeds are require to drill small holes - I say high speeds are nice to be able drill small holes quickly, but whats required (to avoid breaking them) is sensitivity!
instead of sensitivity in the drill itself, the other was is to make a sensitive table. obviously this won't work if you're drilling large items, but is super hand for very small holes, in the higher number series (btw, what is a number 1 and 3 screw?).
make with minimal friction, use a shoulder bolt for the pivot and adjust counter weight to suit work
I have an Albrecht and think its great, made like everything they do. Whether drilling several hundred holes is too tiring depends on the material thickness. If it is 1/4" thick or something like that, it would be. A simple solution would be to rig a lever attached to the ring, reducing the force required and making it easier to break through without snagging the drill. Many years ago, I made a circuit board drill that was just a piece of aluminum angle hinged at one end with a sewing machine motor mounted at the hinge to minimize the effect of its weight and 15" or so along the angle I mounted two 1/8" ID ball bearings with a pulley that took up the space between them. I used carbide circuit board drills with 1/8" shanks and ran them in the bearings with the pulley locked on with a set screw. I used round jewler's lathe belt to drive it. The handle was further out on the angle. The thing swung in a slight arc, but it didn't bother anything. I may still have it around. If so, I could send you a picture. You couldn't do it much cheaper.
Thanks for the comments everyone. One thing I should say is that the several hundred holes don't need to be drilled at once as this is a model engineering project. I just want to solve the problem of accurately drilling small holes.
McGyver, I've seen your small table before, very nice. I've also thought about building a universal pillar tool like the one you have. I ran into yours on the web as part of a search to try and solve my problem. Real nice job.
The thing is, I own a really nice older Sears drill press. Don't laugh too hard, this is a professional model that's pretty well made and has a series of speeds up to something like 7,000 rpm. It's quite smooth and has a very small v-belt of about a quarter inch width that steps up and down two nicely machined aluminum pullies - something of a find.
The Royal/Albrecht gizmo seems like an interesting option, especially if I build a small control arm for it - great idea 9100. Thanks.
I have several of the attachments, with both Albrecht 1/16" and Jacobs No. 0 chucks. But I don't think I have used them enough to say how well one would work for that many holes. I have a 1940's Sigourney sensitive drill press that I have done at least a thousand holes with, which is why the attachments just sit in a drawer.
I don't think Albrecht made those attachments. Some of mine have a company name in California and others have no name. I don't recall seeing Royal's name on one.
There is a guy over on the Chaski forum that makes a small table like that. I suspect he makes a very good table, he seems like a talented guy, and works as a machinist (or maybe he's retired now).
I think he calls the thing a "hummingbird"..... you might go look there.
I dont see a problem with high numbers of holes. I drill thousands of .018 holes in Alum. with them, on an old Wells Index mill that has like maybe 2400 rpm. max. Not near enough, but works fine. I get 2-3 hundred holes per bit, avg about .125 deep holes.
I have an Albrecht. and a Jacobs. The Alb. is better, hands down. The Jacobs has some runout that is murder on little drills.
Here's a little product you might enjoy investigating, a micro drilling sensitive table:
Disclaimer: My pal, Jose, makes these in his home shop. . .
Last edited by Frank Ford; 12-07-2008 at 11:45 AM.
Oh sorry, I'm drilling holes for tapping 1-72 and 3-48 screws in brass. I forget the drill numbers, will have to go out in the shop and look tomorrow. The project ( a 3/4 inch to the foot scale live steam locomotive) will also require some smaller holes as well.
Cheers, Charles Morrill
McGyver, nice sensitive table, that will make a pleasant project.
Presumably the entire table moves?
Sensitive Drill Press
Some time ago Peter S posted several pictures of my little hand operated sensitive drill ( Mystery Miniature Ultimate Eggbeater Drill Press)
The table raises either by hand or auto ratchet mechanism. Even the depth can be preset. There is what I believe to be a date stamped in the base 1898.
It is one of the slickest little gems I have found on ebay.
Looks like the guy I mentioned (J Rivera) is actually the one making them for LMS.....
I see Frank Ford mentioned that above.
Last edited by JST; 12-07-2008 at 09:45 PM.
Little bit pricey at around 2 bills, but nice for repetitive drilling. I have one that I plan to remove from the light factory base and put on the base from a HF micromill, along with a longer shaft for more table to chuck height. I use both the rohm precison chuck and the collet feature.
http://www.minicrafttools.com/38128.html is one source.
Here's another idea. I haven't built one yet, but am getting the part together.