Holes with flat sides - Page 1
Forum section: electronics / beginners

author: Steve
author_rank: Newbie
timestamp: October 04, 2010, 05:51:23 am
content: Hello,I often ask what seem like stupid questions.I am working on project that will use three binding posts mounted in a plastic project box. The binding posts are flat on two sides for the mechanical support so they post will not turn when screwing the wire down. I plan on making fifty plus of these boxes.How to I create a hole in the plastic that is flat on two sides that looks professional, is repeatable, quick and affordable?My idea of enjoyable night does not include routing 150+ holes with a dremel, so I thought that I would pose the question to some experts.Thanks,SteveHere is a link and to the binding post that I am planning on using:http://www.mouser.com/ProductDetail/Emerson-Network-Power/111-0102-001/?qs=sh18mOF39qbg%252b3s0Ynlb5A%3d%3d

author: RayJones
author_rank: Frequent Contributor
timestamp: October 04, 2010, 07:00:11 am
content: Search for "router template guides", especially in terms of woodwork jigs and perhaps rethink your desire not to use a dremel.If you can mount the dremel so it can make use of a template guide this would have to be the quickest neatest way to make repeatable accurate holes of any shape you desire, effectively limited to the size (radius) of the router bit.Failing that expen$ive punches would be the quickest method, but they don't come cheap.

author: sonicj
author_rank: Frequent Contributor
timestamp: October 04, 2010, 07:39:44 am
content: does it have to be a 5-way binding post? or will just the banana jacks suffice?have you considered a star washer? you could drill the complete round hole and use the 1/4" flat's just to hold the connector straight while you torque down the lock nut. a spot of epoxy to the back of nut would help prevent it backing out. should remain reliable for a very long time unless used in a abusable manner/high vibration environment.-sj

author: thakidd
author_rank: Regular Contributor
timestamp: October 04, 2010, 07:59:23 am
content: Not sure what height you are working with but a drill press could work quite nicely...If you have a template setup out of plastic, paper, whatever, you should easily be able to knock out 50 units in an hour. Depending on how you drill and the bit you use, you can have a clean shot for each hole. In the US here...I picked up a drill press with a 1/2" > 7" depth at northern tool for $93 a year ago. Works quite well and can drill all kinds of sideways and what not. Also comes with a foot pedal so you can vary the speed depending on material.Example app...I use it mainly for through hole applications. I can drill a 400-500 hole board in about 3 minutes or so. Just my two cents on a possible proper tool to get the job done. Oh, don't know if it helps but I have used PCB software, CAD, and Microsoft Visio to make printout templates. That may help or may not.Another possibility if you have a Dremel laying around...they offer an option called a plunge router attachment (P/N# 335-01). The depth sucks, but may work on your application.

author: Zero999
author_rank: Super Contributor
timestamp: October 04, 2010, 08:08:16 am
content: I would choose a drill with the same diameter as the thin part, drill two overlapping holes and file.

author: GeoffS
author_rank: Unknown
timestamp: October 04, 2010, 08:20:48 am
content: Quote from: Hero999 on October 04, 2010, 08:08:16 amDitto. Or a round punch with 2 overlapping holes.[I did some similar holes recently on a small metal mill. Very quick and easy but probably not that useful unless you have a mill handy]

author: Zero999
author_rank: Super Contributor
timestamp: October 04, 2010, 09:08:16 am
content: Whoops, I've just realised I made a typo: the drill needs to be the same size as the thin part. I've editid my post.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: October 04, 2010, 08:00:37 pm
content: For professional looking, you need a small mill machine, to make the slots for these is pretty tricky, it has to tightly fix on the hole, otherwise the post will get loose, since the nut will not tight enough to the plastic.This is what I can do with a $200.00 micro mill machine:

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 04, 2010, 11:25:37 pm
content: May be worth investigating lasercutting, if the plastic is suitable.Failing that, find someone with a decent CNC router.

author: EEVblog
author_rank: Unknown
timestamp: October 05, 2010, 03:33:10 am
content: Quote from: Steve on October 04, 2010, 05:51:23 amI have the exact same problem for my latest project.The box costs $1.20 and the manufacturer wants $2.70 to drill the banana plug holes!Sorry, haven't found a reasonable solution yet.Dave.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: October 05, 2010, 04:16:20 am
content: I found out something the hard way with laser cutting. Cutting acrylic makes beautiful holes (even holes for 3mm screws) and the edges are polished when the cut is done, but surprisingly, it leaves the material highly stressed. If you wipe down the cut edge with alcohol, it may immediately have dozens of stress cracks. A hole for a "snap-in" switch may be surrounded by stress cracks when you snap the switch in.How bad this problem is depends a lot on the particular material used (all acrylic is not created equal) and seems to depend on technique too. I have parts cut at Metrix CreateSpace in Seattle, and get much different results depending on who actually does the job.Jon

author: semaphore
author_rank: Contributor
timestamp: October 06, 2010, 03:53:34 pm
content: Quote from: DavidDLC on October 04, 2010, 08:00:37 pmDo you mind sharing what machine is this? I've the same problem here.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: October 06, 2010, 05:49:53 pm
content: It's a cheap one from Harbor Freight Tools branded Central Machinery, unfortunately is not listed anymore, but you can try to get a used one. I'm happy what I can do with it for the price.The pictures are from a solid aluminum box.This is a video of a similar machine (Not my video), later on I will post the correct name since I'm at the office right now.

author: GeoffS
author_rank: Unknown
timestamp: October 06, 2010, 06:39:36 pm
content: Quote from: semaphore on October 06, 2010, 03:53:34 pmThe micro mill X1 bySiegis not widely available. The most commonly available small mill is theX2which is available from a number of suppliers world wide.

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: October 06, 2010, 06:44:34 pm
content: Isn't the Seig stuff LOT more than $200 though?

author: semaphore
author_rank: Contributor
timestamp: October 06, 2010, 07:05:37 pm
content: Quote from: DavidDLC on October 06, 2010, 05:49:53 pmWhere is the video?

author: GeoffS
author_rank: Unknown
timestamp: October 06, 2010, 07:13:32 pm
content: Here's an X1 mill that has had a CNC conversion. It should give you an idea of the size.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: October 06, 2010, 07:14:28 pm
content: Dangin it here is the link:

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 06, 2010, 09:20:39 pm
content: For plastic I wonder how hard it would be to make a custom shaped die for a punch press like thishttp://www.isimatlab.com/ManualPunchPress.htm

author: djsb
author_rank: Super Contributor
timestamp: October 06, 2010, 10:41:57 pm
content: They are called double D punches. Here is a link to a page from the mouser catalogue for Greenlee puncheshttp://www.mouser.com/catalog/636/2102.pdfI don't know how much they are though (unless it's on the above link-It's late and I'm off to bed).

author: DavidDLC
author_rank: Frequent Contributor
timestamp: October 06, 2010, 11:08:26 pm
content: Quote from: JohnS_AZ on October 06, 2010, 06:44:34 pmI got a deal on it, I order it and pay $350.00 and then when waiting for it, Harbor set the price to $200.00, I went and they gave me the differenceProbably they lowered the price to discontinue the item later on.I got a deal !

author: Steve
author_rank: Newbie
timestamp: October 12, 2010, 01:16:48 am
content: Quote from: djsb on October 06, 2010, 10:41:57 pmHello,Thank you for all the excellent advice.The double D punches are a bit on the pricy. But it might be worth it if I do enough boxes, and can get a good deal on one. How do they work? I was not able find any instructions on how to use them.When I envisioned using a dremel, I was thinking of doing all the cuts and routing by hand. On RayJones suggestion I googled “Router Template Guides”. I am going to make a wooden enclosure to firmly hold the project box and mount the router template on the wooden box. Then use a dremel to cut the holes. I should be able to get consistently good results (??). I have started work on it, but it will be at least the weekend before I can try it on a project box.I thought of using a mill, but sadly, do not have one. Although I have been looking for a reason to justify it to the wife, along with a CNC retrofit. Better yet, a laser cutter. :-)I also have contacted the box manufacturer and it was cost prohibitive to have them do the work.Steve

author: GeoffS
author_rank: Unknown
timestamp: October 12, 2010, 01:32:37 am
content: The panel punches I've used require that you drill a small hole in the panel to install the parts of the punch.The actual punching is done with a spanner or allen key.This image may help.

author: RayJones
author_rank: Frequent Contributor
timestamp: October 12, 2010, 06:50:19 am
content: Quote from: Steve on October 12, 2010, 01:16:48 amHi Steve,once you have fabricated a template, you'll be able to push through a heap of panels in no time flat.the best example is dovetail jigs for woodwork. They look hard to make, and they are if done by hand, but with a template guided jig all four corners of a drawer can be routed in a little over one minute once you have the knack of the router and jig.Adding a plunge attachment to your dremel will make it into a nice little template guideable machine and you'll be making panels REAL EASY, quickly and precisely repeatable.Glad you took the time to research the template guidesCheers, Ray

author: RayJones
author_rank: Frequent Contributor
timestamp: October 12, 2010, 07:15:21 am
content: I suppose a bit of elaboration on the setout of your template guide is in order.The biggest challenge you'll face is the need to enlarge the hole in your template to accommodate the required cutout shape (which can be very elaborate if you want).The starting point is to know how large the template guide's bush is (ie the actual stepped down part that will follow your template), and the diameter of your router cutter.Halve this difference to determine how far the inside edge of your template's hole needs to be brought out from the finished edge of the final hole.The smallest hole you can make of course in the panel is the diameter of the router bit, but you'll need a hole the size of the template guide's bush in the template.If you sketch down that concept and understand it, you'll be well on the way to drawing the required template holes.There is the possibility that the template holes may end up being overlapped.If that happens it is best to make two templates with the holes appropriately placed.When you use one, then the other you'll end up with the proper spaced holes in the panel.It may sounds like extra work to make another template, but you ultimately still will need the same number of holes in one or two templates!The template method is so quick and accurate you won't look back :-)Ray

author: RayJones
author_rank: Frequent Contributor
timestamp: October 12, 2010, 07:24:32 am
content: Here you go, page 9 of this shows the template guide usage for the Dremel Plunge attachment:http://mdm.boschwebservices.com/MDMCache/English%20%5BUS%5D//t10/0000000/r00523v-1.pdfWhat a mongrel URL to paste - spaces and square brackets = FUN FUN FUNI feel like I should get one now for my Dremel, my 2HP 1/2" collet woodwork router is tad large for the more delicate panel work I may do one day, but it would work fine for larger holes (router bits)Oh yeah, spiral up cut is the go for the router bit for smoother cutting action and swarf removal.Ray