Mechanical Engineering Problem - Page 1
Forum section: electronics / general

author: German_EE
author_rank: Super Contributor
timestamp: March 06, 2015, 10:08:07 pm
content: Take one aluminum bar, 5mm thick and 30mm wide. How do I drill two holes in the ends of each bar 2mm diameter and 10mm deep. Each piece of bar is 320mm long.I considered making up a jig to fit to my drill press that holds the bar vertically but I am wondering if anybody else has a better solution.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: March 06, 2015, 10:21:15 pm
content: If you have a steady enough hand you could just attempt to put it in a vice and use a hand held drill. If not I can't this moment think of a better solution than your own.Edit: I must admit that I myself do not have a steady enough hand, but I know people who do and have abused their good nature to get stuff done

author: Someone
author_rank: Super Contributor
timestamp: March 06, 2015, 10:52:35 pm
content: For a drill press with a rotating table, you put the table vertical and clamp the workpiece in the vice with the length hanging down. This minimises the amount of unsupported length between the vice and the drill.http://home.comcast.net/~kvaughn65/aux_table.jpg

author: HighVoltage
author_rank: Super Contributor
timestamp: March 06, 2015, 10:55:25 pm
content: I would also drill these holes with a good hand drill.10 mm is not too deep.But you should get a really good drill bit.In Germany, you can get really good drill bits at Würth, take the "ZEBRA" brand HSS-CO and you will be surprised how easy it is to drill these holes.

author: Galaxyrise
author_rank: Frequent Contributor
timestamp: March 07, 2015, 12:43:11 am
content: I would use my drill press. 320mm will comfortably fit under the drill, so I'd probably just push the table to the side and put a vice at the base of the press. But I can think of other ways to mount it that wouldn't be very hard to implement.

author: Galenbo
author_rank: Super Contributor
timestamp: March 07, 2015, 11:04:35 am
content: Quote from: German_EE on March 06, 2015, 10:08:07 pmIt's not in the mechanical engineering field, but machine operator manufacturing.It's a very mainstream operation on this kind of machine:Magic word is "lathe"

author: KJDS
author_rank: Super Contributor
timestamp: March 07, 2015, 12:11:04 pm
content: Quote from: Galenbo on March 07, 2015, 11:04:35 amWhich is fine for round bar, but he'd need a four jaw chuck with a wide throat for a bar that's 30mm wide and 5mm deep.

author: HighVoltage
author_rank: Super Contributor
timestamp: March 07, 2015, 12:54:42 pm
content: Quote from: KJDS on March 07, 2015, 12:11:04 pmWell, he could put the drill bit in to the chuck of the lathe and mount the aluminum bar on the carriage and then move the bar in to the turning drill bit.

author: KJDS
author_rank: Super Contributor
timestamp: March 07, 2015, 05:11:15 pm
content: Quote from: HighVoltage on March 07, 2015, 12:54:42 pmTrue, but it's always a faff getting the work at the right height doing that.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 07, 2015, 05:22:44 pm
content: Quote from: KJDS on March 07, 2015, 05:11:15 pmAligning the 4 claw chuck is not easy either.

author: German_EE
author_rank: Super Contributor
timestamp: March 07, 2015, 06:34:20 pm
content: Please keep the ideas coming because there are two useful ones already. Unfortunately I do not have access to a lathe and (until this thread) I did not realize that a four claw chuck existed. So, If I was to clamp my bar in such a chuck how would it be supported at the other end?

author: KJDS
author_rank: Super Contributor
timestamp: March 07, 2015, 07:04:45 pm
content: Quote from: German_EE on March 07, 2015, 06:34:20 pmIt wouldn't, but to fit a bar that wide through the lathe spindle it would be a big lathe and more than capable of holding something 30cm long provided it was properly mounted in the chuck.

author: ConKbot
author_rank: Super Contributor
timestamp: March 07, 2015, 07:05:03 pm
content: Quote from: German_EE on March 07, 2015, 06:34:20 pmYou'd have a minimal amount of the bar stock sticking out past the jaws, and the remainder would go inside of the headstock (there is usually a small hole in the center of the chuck, and through the driveshaft which turns the chuck)If you only have a drill press though, I'd get a quick-grip type of clamp (bar clamp) and clamp it to the side of the table, and rotate the table to the side. Obviously this depends on the precision you need since you'd just be aligning it by eye. But with a square to make sure the stock is perpendicular to the table face, and if you scribe, center punch, center drill, and do it with a short drill bit to minimize flex, you could get ok results.

author: Galenbo
author_rank: Super Contributor
timestamp: March 08, 2015, 09:19:15 am
content: Quote from: KJDS on March 07, 2015, 12:11:04 pmSorry "bar" translated in my language always means round in that sector, square and other would be named "profile" in my country.What's your requested tolerance to be in the middle, and the tolerance of the hole?What's the number of items to be made?What does the hole serve for? Any other operations to be done?Where does your profile come from? Bought so, or made from another profile?Yes, all very mainstream daily questions in that field. There's no such thing as "a" hole.

author: Galenbo
author_rank: Super Contributor
timestamp: March 08, 2015, 09:36:12 am
content: Quote from: German_EE on March 06, 2015, 10:08:07 pmDrilling a hole 320mm away from the stand looks kind of strange, you also would need an oversize drill to perform a 2mm hole, not always a good combination.You could fabricate a steel bracket/mount/caliber/tool/support/fitting/... that tightly goes over your alu 5mm x 30mm profile (for example cheaply weld some steel profiles together so you end up with something that has a 5mm x 30mm hole)The other side of that mount you make solid with a hole of 2mm, for example 30mm long.That steel mount should then be in total 80mm long, one side sliding 50mm over your alu profile, other side solid 30mm long with a 2mm hole in it.Now put the mount over the profile and simply drill by hand with the cheapest hand drill you can find. The tolerance, position and angle of your hole is defined by your selfmade steel tool.

author: G7PSK
author_rank: Super Contributor
timestamp: March 08, 2015, 10:00:15 am
content: I use a 2 soft jaw chuck with a V milled in the soft jaw in a lathe for square or rectangular bar.

author: woodchips
author_rank: Frequent Contributor
timestamp: March 08, 2015, 09:53:30 pm
content: As has been mentioned, use a jig. You can drill the guide holes where you want, clamp it to the end of the work and drill away. For best results make the hole guide piece at least 10mm thick so it will guide the drill, and not be worn away too quickly.I always use gauge plate for jigs. It is straight, flat and very easy to use unlike odd bits of metal found in the back of a drawer.

author: G7PSK
author_rank: Super Contributor
timestamp: March 09, 2015, 08:37:28 am
content: If you are drilling a lot of holes with a jig it is worth while getting a drill jig bush for it these are hardened and do not get worn away rapidly.http://www.talbot-tool.co.uk/ihlb.htmhttp://www.boneham.co.uk/shop/category/drill_bushes