I`ll be waiting and watching for your daily progress
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:
(http://www.lister-engine.com/pics/lathe/qctp/001-RemovingTheRust.jpg)
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:
(http://www.lister-engine.com/pics/lathe/qctp/002-ShinyCube.jpg)
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
(http://www.lister-engine.com/pics/lathe/qctp/003-Shiny4point7inchCube.jpg)
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):
(http://www.lister-engine.com/pics/lathe/qctp/004-UsingTheEdgeFinder.jpg)
Then, use a large-ish centre drill to make the V-shaped hole I'll need for the next step:
(http://www.lister-engine.com/pics/lathe/qctp/005-CentreDrilling.jpg)
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
(http://www.lister-engine.com/pics/lathe/qctp/006-SetupInLathe.jpg)
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:
(http://www.lister-engine.com/pics/lathe/qctp/007-DrillEm.jpg)
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.
: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
It probably started life more this sort of shape, so its shank could be set parallel to the lathe's axis, but repeated sharpening has removed the part outlined in red. I think it's time to raid the piggy bank and treat yourself to a new one.
(http://i689.photobucket.com/albums/vv257/andyf1108/015-BoringBar-2.jpg)
Hi AdeV,
Nine hours boring, that must have been truly boring. :lol:
I do think you have to revise your methods and quickly.
I was going make a recommendation for a tip, but on looking at current on-line catalogues for Iscar and Sumitomo, the ones I use are not to be found, curse this craze for modernizing everything. Anyway, the ones I would have recommended are truly magnificent. They allow a near chrome like finish, even with very small depth of cut, on all the metals that I use. I shall have to be careful with my remaining stock, as replacing them might prove difficult. :( :(
Hi AdeV, the easy way is to put a torch to your boring bar, remove the small piece of carbide, and replace it with a much larger one, which you can grind to match the picture you show of Andy's suggestion. The long way is to get a boring bar that takes inserts, as it will cut better, and will have good chip control, something difficult to accomplish with the plain brazed bar. Good chip control can double or triple your boring speed if the edge is right. The one I use most has a TPG insert, and gives a good finish, and empties the cavity pretty well when there's room. :thumbup: mad jack
Can't believe you used your nuts for that!! :jaw: :lol:
I'd have thought that the centrifugal force would have kept them all to one side? How fast was it spinning?
Doesn't a tumble polisher move slowly with as stated "abrasive stuff" doing the work over many hours?
Just wondering.... Never tried it myself.
Looking good though Ade :thumbup:
I'm no help what so ever on the technical dimensions question though sorry ::)
Ralph.
O...I just picked a speed where I could hear my nuts rattling around & left it at that...
:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :doh:O...I just picked a speed where I could hear my nuts rattling around & left it at that...
Now I have to clean my keyboard. Soda everywhere! :lol:
Enjoy Spain.
Eric
another excellent write up!
i really am impressed with your work. ignorance is bliss, but also gets the job done!!
as we say at work, if it gets the job done its ok!
Your QCTP is beginning to look very good! :clap:
Regarding your issue when setting the shaft up in the v-blocks. Would it not be possible to set a DI / DTI to the tapered surface, run the X-axis back and forth and adjust the part until you got no dial movement? Just asking because I don't have such a fancy digital angle gauge.. yet ::)
Hi Ade, I keep a starret level on my mill table, it has two bubbles at right angles, and is pretty accurate matching up bubbles pretty close with my machine level, and I often use a level to get a piece in the vise close enough for regular kind of work, like putting a handle on a tool post.
As to dimensions of a large tool block, I suggest you find one you feel is the right size, lay a couple of dowel pins in the female dovetail, use an appropriate sized adjustable parallel to tighten up the dowel pins (they need to be about two thirds the depth of the dovetail slot for accuracy), and measure off the parallel, and use the same pins and parallel when you make your slots. I'd suggest making a "master slot" blank, and use it for testing all your future tool holders, to keep from creeping larger or smaller, incrementally.
Hi Ade, were I me, which I am, I'd use a piece of aluminum bronze if I had one laying around, stainless does gall easily, particularly 303, and the aluminum bronze is about as hard a bronze as you get, and would probably give the best bearing surface for the eccentric. It's probably going to be turned a few dozen times at least, I'd say. Worth taking account for some friction.
I expect once you've got a few tool holders, you'll be as well off as if you bought them, and from then on, all the ones you make, will be as if you'd bought the original post, so you didn't lose much of anything in not finding dimensions. I looked through my catalogs, and books, and didn't find any reference with dimensions of the dovetail in any of them. As long as it's big enough, it'll get you through the day.
I think that spline issue would about drive me crazy, my tractor was doing that a few years ago, ended up having to make a new clutch for the PTO so it'd stay engaged and cut. One of these days I'm going to buy a few roughing cutters, I keep reading about people using them, and they sound like a good piece of gear. Looking good so far :beer: :bugeye: mad jack
.....How does one transfer oil from the big can to the little can, without spilling any, when you've not got a handy assistant to hold the funnel? ......
.....How does one transfer oil from the big can to the little can, without spilling any, when you've not got a handy assistant to hold the funnel? ......
(http://www.lister-engine.com/pics/lathe/qctp/055-PistonIn.jpg)
Eee, just like a bought one :D
Ade,
I meant to show you the adjusting bits I made for my tool holders when you called yesterday.
Instead of making a washer to go under the nut, just get a length of bar the same diameter as your 'washer', knurl the outside for a few inches (50 to 75mm), then drill and tap the same thread as you are using. Part them off to about 3mm thick whenever you want a new length adjuster. Once it is screwed onto the thread for exact height, your nut is then used to lock it into position.
Like shown in the last few pics of this post.
http://madmodder.net/index.php?topic=2323.msg24924#msg24924
"L8r" :scratch: :scratch: :scratch: Oh, "Later" :bang:
Hey Ade, at least your close on those dimensions. I won't think you'd ever notice once the tool holder is done. Quite a pruduction you got going there. :dremel:
Sounds like a new vise is in order here. Make up a few of those aluminum sumps and I'm sure you could get a hansome price. Enough to afford a very nice vice. :)
Bernd
Hey it's 8:30PM here and your still awake at 1:30AM?