Neat way of drilling centre holes in round bar....(non ranty political)
Had a fill in teacher at school last week, showed me a quick and easy
way of drilling a hole through the centre of a piece of round stock, using a drill press and an ordinary drill press (ie, non precision) vise.... 1.Centre punch the bar on the plane where you want to drill. 2. Clamp job in vise, preferably at 90 degrees to drill plane....(use a parralel(sp?) if you want to be fussy, I did it by eye and it was pretty close) 2. then, with a drill bit the same size as the bar, in the drill press chuck, position the vise so it is centered round the drill bit. Clamp vise down with G-clamp. Do this as close as possible to end of job. 3. Swing the table around till the proposed hole centre is under a small pilot drill (I used 1mm, as the final hole was 2mm, and 1mm was the smallest available without hassling the storeman)- how come storeman are universally grumpy buggers? 4. Drill the hole - voila, it will be dead centre. Swap out bits to final size, go for it. Andrew VK3BFA. Yes, I know there are a lot more precise ways of doing this, but it was only a tommy bar for a clamp screw, so was pretty good - especially compared to previous efforts. Was for the clamp for a V- block I had made as part of me Fitting and Machining course....something practical to use at home, while getting a good intro to basic milling and surface grinding.... |
Neat way of drilling centre holes in round bar....(non ranty political)
On Oct 19, 9:22 am, wrote:
Had a fill in teacher at school last week, showed me a quick and easy way of drilling a hole through the centre of a piece of round stock, using a drill press and an ordinary drill press (ie, non precision) vise.... 1.Centre punch the bar on the plane where you want to drill. 2. Clamp job in vise, preferably at 90 degrees to drill plane....(use a parralel(sp?) if you want to be fussy, I did it by eye and it was pretty close) 2. then, with a drill bit the same size as the bar, in the drill press chuck, position the vise so it is centered round the drill bit. Clamp vise down with G-clamp. Do this as close as possible to end of job. 3. Swing the table around till the proposed hole centre is under a small pilot drill (I used 1mm, as the final hole was 2mm, and 1mm was the smallest available without hassling the storeman)- how come storeman are universally grumpy buggers? 4. Drill the hole - voila, it will be dead centre. Swap out bits to final size, go for it. Andrew VK3BFA. Yes, I know there are a lot more precise ways of doing this, but it was only a tommy bar for a clamp screw, so was pretty good - especially compared to previous efforts. Was for the clamp for a V- block I had made as part of me Fitting and Machining course....something practical to use at home, while getting a good intro to basic milling and surface grinding.... Essentailly the same as putting the work into the chuck, clamping the vice, releasing the work, and lowering the table? Dave |
Neat way of drilling centre holes in round bar....(non ranty political)
On Oct 20, 12:32 am, wrote:
On Oct 19, 9:22 am, wrote: Had a fill in teacher at school last week, showed me a quick and easy way of drilling a hole through the centre of a piece of round stock, using a drill press and an ordinary drill press (ie, non precision) vise.... 1.Centre punch the bar on the plane where you want to drill. 2. Clamp job in vise, preferably at 90 degrees to drill plane....(use a parralel(sp?) if you want to be fussy, I did it by eye and it was pretty close) 2. then, with a drill bit the same size as the bar, in the drill press chuck, position the vise so it is centered round the drill bit. Clamp vise down with G-clamp. Do this as close as possible to end of job. 3. Swing the table around till the proposed hole centre is under a small pilot drill (I used 1mm, as the final hole was 2mm, and 1mm was the smallest available without hassling the storeman)- how come storeman are universally grumpy buggers? 4. Drill the hole - voila, it will be dead centre. Swap out bits to final size, go for it. Andrew VK3BFA. Yes, I know there are a lot more precise ways of doing this, but it was only a tommy bar for a clamp screw, so was pretty good - especially compared to previous efforts. Was for the clamp for a V- block I had made as part of me Fitting and Machining course....something practical to use at home, while getting a good intro to basic milling and surface grinding.... Essentailly the same as putting the work into the chuck, clamping the vice, releasing the work, and lowering the table? Dave Ta Muchly Dave - wish I had thought (or been shown) that one. In memory bank for future use..... Andrew VK3BFA. |
Neat way of drilling centre holes in round bar....(non ranty political)
On Oct 20, 12:52 am, "Robert Swinney" wrote:
Andrew sez: "2. then, with a drill bit the same size as the bar, in the drill press chuck, position the vise so it is centered round the drill bit. Clamp vise down with G-clamp. Do this as close as possible to end of job. 3. Swing the table around till the proposed hole centre is under a small pilot drill . . . " It seems to me "swinging the table around" even in a small arc would introduce enough error to spoil the accuracy. Bob Swinney True, was aware of this error potential - (my maths is crap, so no idea what the actual error would be, I couldnt SEE it, so was happy..) the method described by spamTHIS is going to be the one used in future, especially as its independent of having the exact same size drill bit as the material being drilled... I had already cut the thread in the bar, so was limited to clamping the rod on the plain portion. Will do the thread last next time, so I can position the drilling point of the vice better. Hey, it was a quantum improvement on my previous methods, so was feeling pretty good about what accuracy I did achieve.......glad this group is here, get basic information that comes in real useful..... Andrew VK3BFA. |
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