A pleasant afternoon's project.

[GrahamC]

I don't post very much but I do read just about every thread on this forum. My workshop experience goes way back to high school with three years (six semesters) of machine shop practice, an interlude of many years with only a bit of hands on machine work but lots of model making and wood working. The last six years or so has seen me spending much more of time putting together a small home machine shop and I have progressed from a small Taig lathe to a much larger 10 x 22 (or 5 x 22 in English money) size lathe of Asian origin. Also have a drill press, an off hand grinder, and Myford milling attachment for the lathe.

I quickly outgrew the Taig as it had no screw cutting capabilities and as I pondered adding said feature and the cost of doing so I decided to just get a larger lathe with that capability and I haven't looked back since. The Taig is a wonderful little lathe but I simply outgrew it rather quickly.

That is a bit of a long introduction to a pleasant afternoon spent in the workshop. One of my interests and what drives me as to what I machine is my interest in small model glow, ignition and diesel engines. A recent project has given me the need to make several duplicate parts with the requisite desire to make them all the same size. I have a 5C collet chuck for my lathe and though what better way to start making these parts than to use the 5C chuck but if only I had way of indexing the parts so that I could make them all the same size? A collet stop is the answer of course, a stop for the 3 jaw chuck would work too. So, my pleasant afternoon project was to make a 5C collet stop.

The first picture shows the result, the holder which screws into the back side of the 5c collets and two rods that are used to set stop location. A grand total of about four hours of work - one hour of actual machining and three hours of putzing, fussing over details and setting up. All pieces are made of 12L14 or maybe 1018 steel, all came from the scrap bin. I didn't make any drawings, I just measured as I went and machined off any bits that didn't belong to the finished piece. The dark finish of the holder may be of interest. It was done by nothing more fancy than just heating the piece with a Turbo Torch and quenching in oil - I heat the piece for a couple of minutes, quench, immediately heat for several more minutes, quench, immediately heat until a dull red, then quench and let cool in the oil. I do this to almost any project I make of 12L14 or 1018 and it gives a good serviceable dark blue/black finish. The oil I use is a quart of synthetic 2 cycle (Amsoil something or other) - I don't know if the oil being synthetic is advantageous to the fairly dark colour I get or not but I have been using the same quart for quite some time, the results are repeatable and if ever I feel the need to replace the oil I will replace it with the same thing - no need to fix something that isn't broken)

The second picture shows how machine the flat onto the stop bar using a holder in my AXA size QCTP. The rod is held in a 3C collet that is held in the standard AXA size boring bar holder. The photo actually shows the milling of a flat on a much shorter piece of rod. The third picture shows the boring bar holder, a 3C collet and the two pieces needed to hold and tighten the collet. The collet holder pieces are made of 12L14 or 1018, again pieces from the scrape bin. Why I haven't blued/blackened them yet I don't know - maybe one evening this week for something to do.

The last picture shows how I machined the flats on the holder to use with a wrench for loosening the holder from a 5C collet.

All in all, a pleasant afternoon spent in the workshop - now on to making the parts that I couldn't make until I made another piece of handy kit and so the cycle goes on.

cheers, Graham in Ottawa Canada

[dsquire]

Graham

Glad to see that you had an enjoyable Sunday afternoon. Sometimes making jigs, fixtures and tooling is as much fun as making the end product. I too have done the woodworking and Radio Control bit and really enjoy it. I will be watching to see what you build with this tooling. 

Cheers 

Don

[bogstandard]

Graham,

Very nice work indeed, and some good getarounds. It is marvelous how people can come up with ingenious ways of doing a little bit of machining.

I would just like to give you a little warning about your collet backstop. Do not rely on it to give accurate repeatability. The way those type work, is dependent on how tight you tighten up your collet, I always use a marker on the chuck so that I turn the handle on the chuck key to the same mark.
The only way to get true repeatability is to use a spindle mounted backstop. Very easy to make, and while you are in the making mood ............

http://madmodder.net/index.php?topic=1649.0


Bogs

[GrahamC]

John,

Agreed on the repeatability issue. However, any big of tooling or jig can suffer from repeatability if care is not used, even a chuck back stop (ie tiny bit of swarf where it shouldn't be).

That said, I index everthing and have very consistent working habits. My lathe chucks all have index marks and a carefully selected number 1 jaw. I position the chuck the same way each time I open or close it, I mount it the same way and tighten and loosen it's mounting the same way each time it is mounted or dismounted. Any bits of extra tooling and jigs have indexing marks so that they can be used in the same relative way each and everytime. This is not to say that is how reduce error to zero but it does help to reduce potential errors by introducing consistency to how I work.

So far in a few off hand tests, repeatability is my 5C collet stop is acceptable and meets my required target. When I set up and start making the half dozen parts I will initally need to make I perform a bit closer QC and modify any of my process steps appropriately.

I like your posting of the chuck back stop. However, my lathe has a 4mt spindle and I cannot fit a 4mt arbor through from the front of the chuck. I will need to make an expanding chuck stop of some sort that I mount from the headstock side. Easily done and on one of my "to do" lists but an immediate need has never prompted me to make one up.  Incidentally, I purchase a couple blank end 3mt and 2mt arbors every time the local supplier has a sale. I keep a couple of each size "in stock" as they are very handy for making jigs and tooling as you have noted - slitting saw arbors and mini faceplate/work holding jigs to name a couple. I use the 3mt with a 4mt to 3mt adapater in the spindle - the adapter suitably indexed as are the arbors so I put it in the same way each time even though several careful measuresment have shown it makes little difference as the runout is always very near zero regardless.

cheers, Graham