Mark, Copied to PICLIST as there may be others there with some knowledge of this. >The next hurdle after that is to drill some REALLY tiny >holes (like 0.005") for ullage vents, I REALLY am not looking forward to >that! The flute drills are ~$7ea. and only come in packs of 10...I'm >positive that I'll be breaking a few of those(probably off in the work >:-(!) I haven't tried this but you may find that spark eroding is a viable method for such small holes and you may be able to make an eroder at lowish cost and without too much effort or electrical knowledge. I'm an electrical engineer but have only noted spark eroders "in passing". I believe they mechanically offer up a work-piece to the surface with an appropriate source of current connected. For a very small diameter workpiece the current requirement could be quite small to get a large current density at the contact point. It may well be that a capable plug pack ("wall wart" where you are I believe) would suffice or for a little more go a car battery charger. Perhaps add a large surplus capacitor to either for more initial current. I don't know the relationship between stylus area and hole size but I imagine the hole is "somewhat" larger. You may need something like an 0.0025" (0.1mm) dia stylus. This can probably be a "whisker" of high tensile wire. The ullage hole dia is probably not too critical. Russell McMahon _____________________________ >From other worlds - www.easttimor.com www.sudan.com What can one man* do? Help the hungry at no cost to yourself! at http://www.thehungersite.com/ (* - or woman, child or internet enabled intelligent entity :-)) +++++++++++++++ Left intact for others' interest. -----Original Message----- From: Mark Casteel To: AROCKET@ITC.UCI.EDU Date: Monday, 7 February 2000 17:20 Subject: Re: [AR:] Lathes and Lasers >Hi Al > >Also being the recent proud recipient of a chunk of chinese supposed >cast iron doubling as a lathe... I also need a MT2 drill chuck. >Staring off into space after huffing ways too many cosmolene/kerosene >fumes, I noticed that the ancient chinese drill press came with a MT2 >chuck...now I positively remeber this because it kept falling out and >wouldnt stay in the press either... might check around the tool refurb >shops for one. > >Another option to make the taper is to offset the tailstock some known >amount, cut a piece of steel some known exact calculated length to get >the taper you want. If you have powerfeed you can then make a tapered >piece far longer than your cross slide travel, still relatively easy w/o >powerfeed. Another option might be to get a precision 12" rule, put a >round true reference piece in the lathe, build a jig to hold said >straight edge, get an accurate enough mic, and measure out the distance >that the 12" rule needs to be off the reference, and then somehow >transcribe this to the cross slide. Yet another option(which might be >the far easiest) is to get a buddy that has a milling machine and have >him cut a thick refernce block with the angle needed that you can align >between the travel and the cross slide. I personnaly am going to have to >get a block made like this but square since that appears to be the >easiest way to square up the cross slide for doing a square facing >operation. > >My current personal fiasco is to figure out how to turn some 0.030" >stainless steel on the lathe to form some large washers to back up the >nozzle... so far my best idea is to secure the stainless to a piece of >hardwood attached to the face plate... theres gotta be a better way >though. The next hurdle after that is to drill some REALLY tiny >holes(like 0.005") for ullage vents, I REALLY am not looking forward to >that! The flute drills are ~$7ea. and only come in packs of 10...I'm >positive that I'll be breaking a few of those(probably off in the work >:-(!) > >mark > >al bradley wrote: >> >> I wrote: >> >To our machinists on Arocket on a matter I wrote of to the list earlier: >> > >> >I have verified to my own satisfaction that a common laser pointer on a >> >homemade bracket can be accurately targeted to show run-out and/or >> >out-of-round on rotated lathe work. My target was at 14 feet, but if your >> >lathe is in a good location to a longer target distance, accuracy would be >> >even greater. >> > >> >Next mind-bender (for me) is to find a way to mount the laser pointer so as >> >to set the cross feed exactly parallel to or at a given angle to the lathe >> >rails. >> > >> >Thoughts, ideas would be appreciated. >> > >> >respectfully >> >al bradley >> ------------------------ >> and Paul Kelly responds: >> >> >Two lasers! one sits on the bed, just clamp it to an angle, the other on the >> >slide. Measure the distance between the dots. >> > >> >> I have an error in what I wrote above -- I really wish to set the >> *compound-rest feed* to parallel or angle! >> >> >I gotta know, what angle needs to be so precise that the micrometer scales >> >don't cut it? >> > >> > >> >PK >> >> ------------------------------------------------ >> >> Well, I expected to have a number of spoiled-pieces as a beginner working >> out of American text books on a Chinese lathe but the one project that I >> spoiled a number of pieces in a row was when I wanted to mount a Jacobs >> chuck to the tail stock. The threaded end was no trouble on the lathe but >> I also needed to turn a Number 2 Morse Taper for the other end. >> >> No. 2 Morse taper shows a taper of .5994 per 12 inches. Trigs out to an >> angle of 2.8 degrees if I haven't screwed up the math. The half-angle the >> compound rest would need therefore should be 1.4 degrees and the micrometer >> scale for that doesn't fill the bill by a long shot. The travel of the >> compound-rest is only 2.362 inches, and I am not absolutely sure that the >> screw feed is parallel to the side of the compound rest, so when I tried to >> make up an adjustable gauge to set my angle I still didn't get a really >> good, tight fitting Morse Taper. >> >> Therefore lies my interest so far in cutting angle work and being able to >> set the compound rest by extension of a laser beam. Maybe I am making a >> hard job out of it. Nozzles don't seem to be near so fussy to make. >> >> Another area that is consistently troublesome is to get a really accurate >> center-punched countersunk hole in the workpiece to fit the tail-stock >> center. Seems to move off center during the drilling. Ideas? >> >> Best regards, >> al bradley >