Little Atlas 618 with a BIG cross feed dial.

[Takdashark]

It broke almost at the center line. I attached some pics. I'm going to explore some options, I have silicon bronze filler rod for my tig, and aluminum brazing rod for making AC lines. Ok I'm done hijacking your thread. Thanks a bunch David!

Taki,

 

[makeparts]

Making the dial. I won't describe the actual machining..just standard stuff. I had to figure out how to make the graduations....100 in all.

First was to make an index wheel. Using Viso mechanical design I made a index wheel with 100 graduations, every 3.6deg apart. I color coded the graduations. Red for the 10s, green for the 5s and black for the thous. Printed in in hi res on glossy photo paper and mounted it to a thin aluminum disc with double sided tape. Fortunately for once I thought ahead a bit and before I set up to machine the actual dial I installed a collet in my spindle and snugged it up with the draw bar. Now I could remove the draw bar and use it to lock the index to the back of the head stock spindle. To make the graduations I decided to engrave them. Installed the headstock and milling column from my Unimat lathe onto the cross slide of the 618, centered it and locked it down by tightening a gib screw on the cross slide.

I don't have a way to lock the atlas chuck from rotation. I used sort of a prony brake with a piece of webbing, fixed to the bed, wrapped around the chuck with about a three pound mass on the free end, and always turning the chuck backwards to index.

Graduations were down in three passes / rotations. First for the 10s cut in to about 1/2" set the carriage stop and did the remainder, then moved into about .3" for the 5s, and finally the thous.

All is good so far. By the time I was done...well I was just glad to be done. Tore the set up all down, and then said "damn" I forgot to mill flats under the 10s so I could use numeric marking punches to mark the major graduations. Ended up trying to punch them on the round and didn't do so good on some.. so not going to show that....embarrassed.

Index set up
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Unimat mounted on cross slide for engraving

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At the zero mark I used a thumb screw to lock the dial to the shaft. It is drilled all the way through with a #36 drill bit and then the dial is reversed and a #25 drill is drill back to just inside the collar below the locking screw, so that an intermediate piece of brass is installed to do the locking on the shaft to prevent galling.

To make it more readable for my ol eyes I put nail polish in the 10s and 5s graduations.

Finals here

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David

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Saw this old thread, and am contemplating building something similar. I don't have a Unimat, but I do have a working MICA undercutter for my lathe (sleeve bearing Craftsman 101). The way these undercutters mount, the blade rotates perpindicular to the workpiece (parallel to workpiece rotation).

I guess I am wondering if I could use the undercutter to engrave the graduations... if I can, would I need to use a different type of blade other than those supplied with the undercutter? (It came with 1 blade that is very small in diameter, so I probably need to get some new blades from clausing or some other type of very small arbor cutting blades, or make my own arbor for the undercutter, to fit whatever blades I might use).

thanks in advance for any advice
David