Countersinks angles

I enjoy the challenge of making parts for my model helicoters and have had great help on this site with learning how to perform simple engineering tasks. My problem is that whilst I enjoy the practical side, I don't have my own machines and rely entirely on using a neighbours workshop. Add to this that I usually end up buying my own tooling and large pieces of stock, it works out extremely expensive. What is the best way to find a small workshop that is happy to perform small jobs? The drawing below is an example of the type of parts I need.

Hi,

For work on carbon you need a carbide or better still a diamond cutter as HSS has a very short life. Another way I have found OK is to make a solid point on a piece of MS or alloy bar and super glue some wet and dry abrasive paper to it. It does not last long but it's cheap and the paper is easily replaced. When counter sinking I use a hand brace, that's fast enough.

Cheers

John

Edited By elanman on 19/02/2012 17:02:12

All metric countersunk screws should be 90 degree.

You might find that the North American screw threads are 82 degrees; although I live where the UNC/UNF reign supreme, I use solely metric, so don't quote me on other threads, like BA and ME!

I generally use a 90 degree countersunk; most of mine are about 6 flute. Take it slowly for metal, the cutting surface is rather large. (don't know about fiberous non-metalic surfaces)

In theory, you should have a countersink that matches the OD of your screw head so that there is a very slight parallel where the widest part of the screw head is, so that the screw head goes flush, but the countersunk hole does not look overly large. I generally just don't bother worring about this part!

Another JohnS.

pgrbf,

Even if you can find a "local" jobbing workshop, you will still be paying for minmum purchase of material to suit your job and also be paying their overhead costs (wages, rent, tooling etc), so I doubt it willbe cheaper for small jobs.

K

If I could find somewhere local I'd be happy. I can't!

Even if tools and materials are relatively inexpensive, a company like MSC charges £10 for delivery to Ireland. So if I need a 2.05mm jobber, and can't get one locally, ordering from UK costs a fortune.

I'd rather give the money to someone who knows what they're doing and not have to worry about when my neighbour will have time to help me out.