| Gallery, Projects and General > How do I?? |
| Accurate Drilling - centering microscope, USB cam, optical punch? |
| (1/8) > >> |
| raynerd:
One of the things I`ve always struggled with the accurately drilling holes in sheet metal, where I want them!! As most of you know, I`ve been playing at building a clock and feel I`m getting there slowly in terms of the skills needed but of course drilling pivot holes exactly where they are marked is critical! Also, these holes are drilled sequentially as the back plate is built up as and when the wheels are made and so it would be sole destroying to muck up the drilling of a later hole, and mess the plate up for the rest of the holes drilled! I need to come up with a better more reliable method of spotting and drilling holes very accurately on sheet brass. I`m currently accurately marking out, punching and then drilling. Firstly, my punch mark isn`t always perfect (do I need an optical punch), if I do punch accurately, the next issue is aligning that punch hole up to be drilled on the mill (do I need a centering microscope). I often find that my holes a little out of the centre ligns marked when I look back at the drilled spot. This doesn`t really matter at present but soon when I get to drill out for pivot holes I`ll need to be "spot on!" I`ve been thinking about an optical centering microscope for a while as hemingway sells a kit for £100 but I have also seen these USB webcams with this free software: http://www.miketreth.mistral.co.uk/centrecam.htm There seems to be lots on the web about people building these USB cams and using CentreCam but all the posts seem to be between 2006-2009 and nothing more recent! I can`t seem to find any more recent USB cam developments but this looks to be a serious consideration. Any advice or info welcome! |
| John Stevenson:
If you are drilling on the mill why not use the dials / DRO [ if fitted] to lay the holes out ? John S. |
| modeldozer:
Hi Chris, Something like this? If you want I can search for my build pics and plans, it uses one of the Logitec VGA webcams. Abraham |
| HS93:
yes Please Peter |
| PekkaNF:
I struggling with accurate placed and geometricly true as well. I don't know what size of holes you do, but I imagine small. It makes a difference. I usually work bigger than about 1 mm. Most often between 3 to 12 mm. I had a lot of trouble popping the centre mark and then getting the hole there. I only work either markking and I read no dials, or marks first hole and then there are only permanet marker crosses to eliminate complete mistakes if I use dials. 1) Drawing the line. I found out that I'm better off scribing the lines straight and holding the scriber straight, note that this will require some off set from the rule, if you are using it. Canted scribe line does not "crab" the punch to correct location. Something to do with the burr or something, hard to imagine that slighty inclined groove would send it on the other side. 2) Popping the mark on the right place: a) Use small sharp 60 decree to get the punch on the right place. b) Locating the intersection: I'll draw the punch on the line until I'll feel the "intersection", you probably want to draw the line you draw last, othervice you'll bump the "wall" of the other line. c) Punch absolutelu upright and LIGHT tap to get very small pip. 3) Inspection: mark can be driven with a gentle taps close the final location. If driven or uneven burr, I always file the surface smooth, the uneven wall will play havoc 4) If the hole is large I finaly pop centre with larger 90 decree punch and check it again 5) I aim that punch visually, larger drills will pull light objects centre, when gently touched with a drill, but wiggler works also for me. 6) I have found that using spotting drills will put the hole exactly where aimed. Pop rivet drills come close second, but I have no luck with normal drills, they wander all over. There are many different types of drills, many will drill happily after they have good centre to start, but on thin drills only spotting drills seem to get the start right (I use 3 mm quite often). Sometimes I'll locate first hole with a wiggler and then work from there a dial indicator, works only a very small distance, but with very good accuracy. Biggest improvements I had was to learn to make the punch right, most of the time I'll file the "crater" even and the correct drill will make or break it. I'm not sure if this helps, but when I drilled PC boards and such, learnt little about drils. Pekka |
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