| Gallery, Projects and General > How do I?? |
| Another boring question... |
| << < (2/3) > >> |
| AdeV:
Update: Hmm, it's looking like the gun drill might not be the answer after all :( They need forced lubricant to work, apparently, and I don't have that; and it's not worth spending £1200 to add a suitable unit, just to drill a few holes. The gun drill chap is looking into some alternatives for me, should have an answer tomorrow. Another chap reckoned a D-bit might do the job, and that's certainly worth investigating if the gun drill source isn't fruitful. |
| Jonny:
Done similar things in aluminium and about that size, unfortunately that was on a lathe. Reckon method 2 but you will need to extend a couple of drills. What you want to do is drill a smaller hole say 13 to 15mm tops then same size with extended drill, it will self centre previous drilling but will have to keep pulling drill out for swarf clearance ejection. Drill again dependant how accurate it needs to be if using reamer say 15mm down to depth. Same again with 5/8" extended reamer it will straighten out if at all any hollows and follow the hole. Never done that deep but cant see any reason why not. What you dont want is the swarf sticking to the drill so use coolant and keep removing the drills after a certain depth, you will get the feel. In this case on Bridgeport you can lock the quill and wind in the bed with job on, so much easier, just clock the job up. |
| Bernd:
Here's another alternative. Make a spade drill. The shaft can be smaller than the drill bit end taking care of chip build up. Make up size to suit. Bernd |
| Bernd:
I'd use a regular drill press mounted to a table or floor model if you have one. I would then swing the drill spindle so it would clear the bench. The part can sit on the floor. Make up some long drills by using extentions silver soldered on the ends of the drill to make a longer drill. There's more detail to this than I've written but it should give you the idea. Wish I had some pics of what I mean. Would be a lot easier to understand than typing 1000 words. Bernd |
| AdeV:
Thanks for the extra ideas, please keep 'em coming. I'd like to do this myself, rather than outsource it; especially as the aluminium billet is going to be a tad expensive... For what it's worth: - Hole size accuracy is not critical; some kind of fitment will be tapped & screwed into the ali after the other machining operations are finished. The current pipe stubs are 5/8" (16mm) ID, so I'm aiming for about that size. - Hole location & direction accuracy doesn't need to be super-accurate, although it does need to be "near enough". The idea is, the three channels run alongside each other (but aren't joined); and have holes cut in the top of them for each 3rd of the pan. So long as the tubes stay within the aluminium block, and ideally don't break through into each other, then that's near enough. - Hole straightness - again, not critical, so long as it doesn't break through the bottom of the block, or into another channel. I reckon the Bridgeport, with a suitably long drillbit of whatever the "correct" form ends up being, should be well capable of the accuracy required. Whether I buy or make the drill bit remains to be determined.... Bernd; Interesting idea with the spade bit; Wikipedia reckons they're good to 10x diameter (which would give me ~6.25" depth), but maybe I can go deeper within the tolerances I've got. Also, I do have a (heavyweight) drill press, which would be big & ugly enough to cope with the job... but it's got wobble like you wouldn't believe. Fine for roughing out really big holes, but I wouldn't trust it with this job. |
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