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| AdeV:
I'm still waiting for those pesky taps to dissolve from my aluminium sump, and I can't muster up enough enthusiasm to finish off the spindle sleeve taper thing just now, so - what better than another new project :) I was going to try to keep you all guessing as to what it was, but there's a total giveaway in one of the photos, so I'll just come clean now. It's yet another quick-change tool post... My 4-way TP drives me mad, it's a complete git to get the tool height correct, and somehow 4 tools just ain't enough. Anyway, on with the fun. Ages ago, I picked up a roughly cube shaped lump of Mystery Steel (plain carbon steel as far as I can tell). It machines well enough once the thin layer of mill scale & rust was removed: For those who are interested: 0.100" deep cut, approx 10-12mm width of cut, using an 18mm rough cutter. Coolant is regular cutting oil. Anyway, it took a couple of hours, but I ended up with this: It's not quite cubic: It's about 5"x5"x4" - well, it was... it's about 4.8" x 4.8" x 3.8" now :D Next up, a bit of on-material C-o-C work, just to give me the rough positions of things. The centre point of the eccentric cam is punched & the circle scored, just for reference. Next up, pop it back on the mill & use the edge finder to get a datum point (the corner): Then, use a large-ish centre drill to make the V-shaped hole I'll need for the next step: Annoyingly, the centre drill then did what John Stevenson always says they do, and broke it's small flutes off. Grrrr. So, turn the piece upside down, repeat the edge-finder step, turn the centre drill over & pray that this side doesn't break too.... It didn't luckily, so I could move it over to the lathe: In the pic above, I've squished the piece into the two parallels (which are up against the back of the chuck - and are obviously removed before switching the lathe on!) using the dead centre in the tailstock. This allows me to really quickly do up the 4 jaws to grip the piece nice & tight, and I can be sure that - within the sort of accuracy I need here, which is pretty slack TBH - the hole is centered. The parallels are there because, when I come to bore the hole out to dimension, I need to be able to get the boring bar all the way to the back (top) of the piece. Since the chuck centre is less than the 3" diameter I'm aiming for, I couldn't have the metal right to the back of the chuck.... Anyway, without further ado, I started drilling. Eventually, I got to the biggest drill I have. Here they all are, in the order I used them: There's a couple of scary-big steps there, but all went well. The drill sizes are: 6mm, 8mm, 10mm, 1/2", 21/32", 3/4", 53/64", 7/8", 31/32" and 1". I kept the speed down to 190rpm to avoid throwing that block of metal anywhere... It would do a lot of damage I reckon... Tomorrow I must re-mount the boring bar (YAWN) and open the hole out the rest of the way. [edited title for search engines] |
| raynerd:
:clap: :dremel: :clap: :dremel: :clap: :dremel: :clap: :dremel: :clap: :dremel: Nice one AdeV! This is going to be a 100% definate project for me and fairly soon as well. I did start one a while ago but mucked it up on the shaper when cutting the dovetails. This time I`ll do it on the mill. That being said, I`ve no steel big enough to make it and although I like a good project :proj: I do have others that I`d rather do, so I`m just working out by the the time I`ve purchased the steel block, it may have been worth just buying the QC tool post and making some holders! - but then where is the pride and fun in that :dremel: I`ll be waiting and watching for your daily progress :whip: :whip: :whip: |
| AdeV:
Thanks Chris :) --- Quote ---I`ll be waiting and watching for your daily progress --- End quote --- Hmm, it won't be daily for long.... I swan off on 2 weeks holiday after the weekend, so I may not have it finished by then... will try to, though. |
| madjackghengis:
--- Quote from: AdeV on August 09, 2010, 04:34:14 PM ---I'm still waiting for those pesky taps to dissolve from my aluminium sump, and I can't muster up enough enthusiasm to finish off the spindle sleeve taper thing just now, so - what better than another new project :) I was going to try to keep you all guessing as to what it was, but there's a total giveaway in one of the photos, so I'll just come clean now. It's yet another quick-change tool post... My 4-way TP drives me mad, it's a complete git to get the tool height correct, and somehow 4 tools just ain't enough. Anyway, on with the fun. Ages ago, I picked up a roughly cube shaped lump of Mystery Steel (plain carbon steel as far as I can tell). It machines well enough once the thin layer of mill scale & rust was removed: For those who are interested: 0.100" deep cut, approx 10-12mm width of cut, using an 18mm rough cutter. Coolant is regular cutting oil. Anyway, it took a couple of hours, but I ended up with this: It's not quite cubic: It's about 5"x5"x4" - well, it was... it's about 4.8" x 4.8" x 3.8" now :D Next up, a bit of on-material C-o-C work, just to give me the rough positions of things. The centre point of the eccentric cam is punched & the circle scored, just for reference. Next up, pop it back on the mill & use the edge finder to get a datum point (the corner): Then, use a large-ish centre drill to make the V-shaped hole I'll need for the next step: Annoyingly, the centre drill then did what John Stevenson always says they do, and broke it's small flutes off. Grrrr. So, turn the piece upside down, repeat the edge-finder step, turn the centre drill over & pray that this side doesn't break too.... It didn't luckily, so I could move it over to the lathe: :bugeye: AdeV, I always use the smallest center drill I think will work, while rotating the work or drill as fast as possible, with a very light touch, hoping to get a single edge cut, as that establishes an accurate center, and only then move up in center drill size. I have also found that with magnifying "optivisors" I can re-sharpen the small edges of the center drill pretty accurately, and keep them cutting cleanly. This is something I've only recently began to do, having too many experiences with broken off center drills. Keeping the center drill sharp, and letting it essentially single point the center has saved lots of center drills in the past couple years and improved my accuracy of hole location. :poke: mad jack In the pic above, I've squished the piece into the two parallels (which are up against the back of the chuck - and are obviously removed before switching the lathe on!) using the dead centre in the tailstock. This allows me to really quickly do up the 4 jaws to grip the piece nice & tight, and I can be sure that - within the sort of accuracy I need here, which is pretty slack TBH - the hole is centered. The parallels are there because, when I come to bore the hole out to dimension, I need to be able to get the boring bar all the way to the back (top) of the piece. Since the chuck centre is less than the 3" diameter I'm aiming for, I couldn't have the metal right to the back of the chuck.... Anyway, without further ado, I started drilling. Eventually, I got to the biggest drill I have. Here they all are, in the order I used them: There's a couple of scary-big steps there, but all went well. The drill sizes are: 6mm, 8mm, 10mm, 1/2", 21/32", 3/4", 53/64", 7/8", 31/32" and 1". I kept the speed down to 190rpm to avoid throwing that block of metal anywhere... It would do a lot of damage I reckon... Tomorrow I must re-mount the boring bar (YAWN) and open the hole out the rest of the way. --- End quote --- |
| AdeV:
--- Quote from: madjackghengis on August 10, 2010, 07:44:04 AM --- :bugeye: AdeV, I always use the smallest center drill I think will work, while rotating the work or drill as fast as possible, with a very light touch, hoping to get a single edge cut, as that establishes an accurate center, and only then move up in center drill size. I have also found that with magnifying "optivisors" I can re-sharpen the small edges of the center drill pretty accurately, and keep them cutting cleanly. This is something I've only recently began to do, having too many experiences with broken off center drills. Keeping the center drill sharp, and letting it essentially single point the center has saved lots of center drills in the past couple years and improved my accuracy of hole location. :poke: mad jack --- End quote --- Hi Jack, That's definitely what I did wrong with the first hole, I only had 550rpm on the spindle. I upped that to 1200 or therabouts for the 2nd hole. Most of the time, I reckon I can just use a stub drill for hole location (in the future), but this is one time when I actually needed a real centre drill... Thanks for the info on sharpening; this is something I've not yet dared try my hand at... I still have loads to learn before I try sharpening drills & end mills... |
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