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| andyf:
If the position of the job on the table permits the work to be brought close to the collet or whatever is holding the drill (this should be possible, or you wouldn't be able to drill the hole to full depth), I'd use a short, non-droopy drill of the same diameter to drill a few inches in, then wind the job away, fit the long drill, and proceed to full depth. Counsel of perfection (well, after a couple of pints, it doesn't seem too bad an idea :lol: ): arrange some crude support for the middle of the long drill, so it doesn't sag. Some sort of jack with a generous flat top, brought up to the drill near the collet and then moved out to the mid-point, might do the trick. Andy |
| AdeV:
Stormin - that's an interesting idea, I'll have to look into laser pointers. They seem to be cheap enough on eBay; I wonder how true they point when chucked up in a collet... Dave - I think the taper is the other way around to what you think - i.e. the "fat" end of the drill is the pointy end, and it narrows towards the shank. This makes sense from a chip-clearing perspective, and also it means you're never cutting on the full length of the drill. Mind you, it does make you wonder why they bothered fluting it all the way to the end... since I can only cut around 10mm at a time in the aluminium. Also, the drill does whip very alarmingly if run in free air (no prizes for guessing how I know this...), I'd reckon that a short block wouldn't offer much support after 1/2 the drill length had passed through it; also, because of the taper, it would start cutting oval in very short order, I reckon. Andy - I know it's a looong time ago, but way back on p4, that's exactly what I did with the wax model. I used a 16mm end mill (Not sure why, I have a 5/8" end mill... hm, maybe I don't have a 5/8" collet). I also did that when I did the trial hole in aluminium, which is on p5... I'll be doing it again this time too :thumbup: FWIW, and in case I'm being unclear, I'm only concerned with the drill bit drooping while I try to get the head set up perfectly horizontal. Once drilling has begun, the hole supports the drill, so it doesn't appear to wander at all. |
| usn ret:
Ade, a length of white steels/drill rod held in your collet would not sag and you can check squareness over the lenght of the rod to get the desired degree of trueness. Hope this helps. :beer: Ypur project has a much larger audience than you know. I am impressed with your progress ao far. :hammer: Measure mannnnny times cut once!!!! :wack: Cliff :beer: |
| Stormin:
--- Quote from: AdeV on March 22, 2010, 10:01:25 PM ---Stormin - that's an interesting idea, I'll have to look into laser pointers. They seem to be cheap enough on eBay; I wonder how true they point when chucked up in a collet... --- End quote --- Easy way to tell is watch if the mark dances about on the wall when you set the spindle revolving. Forgot to complement you on the machining and ingenuity shown so far on this project, keep up the good work. Be nice to see the finished car but it sems to be missing from your first post now. Edit: It's seems to be back again now. I'd forgot it was a Capri and not BMW this engine was going in. |
| DMIOM:
--- Quote from: AdeV on March 22, 2010, 10:01:25 PM ---Stormin - that's an interesting idea, I'll have to look into laser pointers. They seem to be cheap enough on eBay; I wonder how true they point when chucked up in a collet... --- End quote --- OK - if you get a self-contained laser pointer, you could pop it in a collet and then spin by hand or at low speed whilst watching the image on a card as far away as practical - at least as far away as your drill is long. If the spot gets bigger when its spinning, then its describing a circle and needs nudging to true it up. Then, when running true, "erect" a target which you can secure to the bed, mark where the dot is and traverse the table and check that the dot stays static. Dave EDIT cross-posted at same time as Stormin ! |
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