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| C3 Upgrade and improvement - I hope |
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| PeterE:
Hi Andy, I have a metric machine so both the dials and the markings on the tail stock plunger are in mm. The lead screw is an ordinary Rihgt-hand thread, menaning that I have to wind the new handle counter_clockwise to send the saddle towards the head stock, quite contrary to the tailstock or the slides who have proper LH threads (moving the item away from me when turning clockwise). A crazy thought passed through my head to use a gear to change rotation to make it more natural and perhaps at the same time make that gear an angled gear so that the hand wheel is oriented like the saddle hand wheel - I think one of the WABECO machines do it that way. But that is for the next round there is still things to do until finished with this round. Thanks for the link to the graduation document. Very informative. I have also read up on the subject in George H Thomasīs books and as well tried GHTīs way of engraving the graduation lines, works well. The biggest problem will be to calculate the proper number of divisions to get a useful dial. 0.025 mm / line seems to be a common target that works both for metric and imperial machines, hmmmm. For stamping numbers I will use GHTīs Universal Pillar Tool of which I have made my version of. Work continues ... |
| andyf:
Gosh, Peter, I never realised minilathes had RH leadscrews! Have looked at a pic of the change wheels set up on one, and they obviously do. I stand corrected! I modified Mike Burdick's method (the one in my link) with a crude but effective depth stop to get the dial lines to uniform lengths for the units and the 5s and 10s, respectively. If you're interested, details 3/4 way down this page: http://andysmachines.weebly.com/miscellaneous.html I like your pillar tool. The base and column of a very antique bench drill have been hanging around my garage for 10 years, asking me to make something similar. Andy |
| PeterE:
Well I didnīt think so either until I got my machine. The lead screw on my MJ-189 is a LH thread so I just took for granted that it would be the same on the C3. It was a surprise to find the contrary. If I could make a wish I would wish for a 2 mm pitch LH ACME thread lead screw. That would be extremely useful compared with the 1.5 mm pitch. The MJ-189 have a 1 mm pitch LH thread that works beautifully. Distance calculations are so easy to do as required. When it comes to graduating I have already made a tool to set the lines, the right one in the picture below. ... I tried it when graduating a micrometer stop and it works well. The three pegs are pre-set for the different line lengths and the "star" is turned forward for 5īs and backwards for 10īs. Clips on like a saddle stop on the bed. For setting up I use a suitable distance between the 1īs peg and the saddle when the graduating tool is just in position to start graving the line. Removing the distance the other lines are automatically correct in distance. The old bench drill sounds like a good base for a pillar tool. A lot of work will be spared and can be concentrated on the important bits :thumbup: BR Peter |
| andyf:
Hi Peter, Ooh err! That depth stop is a bit sophisticated! I suupose you might be able to source a 2mm pitch LH trapezoidal (Acme style) leadscrew of similar diameter to your existing one, but the half nuts to suit that and yiour apron might be a little more taxing. A project too far, perhaps. I'll have give Ye Olde Bench Drill a proper coat of looking at, and consider how much of the column needs to be turned away before what comes off changes from rust-red powder to swarf. Andy |
| PeterE:
Hi Andy, The depth stop perhaps look sophisticated, but it works, thatīs enough for me. Well, the 2 mm pitch lead screw idea is probably a bit too mad for a project, you are right there. On the other hand, your bench drill to tapping tool conversion seems to be slowly advancing, a project in the making? Don't forget pictures :D BR /Peter |
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