Lathemaster 5-C Chuck

This is the new Lathemaster 5-C Collet Chuck and the adapter back plate. The parts in front are also supplied but I had no need for the shorter bolts. The 8x14 Lathemaster lathe uses a set of shorter mounting bolts to hold chucks and back-plates in place.

A closer view shows the superb workmanship on these two items They look accurate just setting there. Note the one piece chuck body.

This is a picture of the stock four inch 3-jaw installed on the lathe. I always place a piece of wood or folded towel padding on the ways when changing chucks. I wanted to show that I have the board over the front V-Way as in most of the other shots, the board is moved back. I should put a groove on the bottom of the board, then it wouldn't move.

The new head is so accurate, the old 0.001" indicator (on the left) isn't accurate enough. I bought a new Grizzly 0.0001" (that's one ten thousandths -- sometimes called "tenths") indicator.

I am indicating the original outside diameter of the lathe spindle flange. Variation was 0.0002" total! "Not too shabby" as I used to remark when I was a kid.

The face didn't fair as well, but still pretty darn good for stock. The raised face shown here was 0.0010" total run-out. This surface is non critical as it only interfaces with air. The outside step-down edge indicated 0.0007" Total run-out. This is the surface the chuck or adapter plate seats against.

I took very light "skim" cuts off both faces. In the picture is visible the very fine curls the tool made on the facing cuts. Both cleaned up to less than 0.0001" run-out. A "dusting" cut was made on the edge of the smaller flange just to clean it up.

This step is actually unnecessary. I wanted to make sure all sides of the adapter were as true as possible. I don't have a surface plate and gauge so I came up with this. I mounted the adapter backwards on the now true spindle flange. If I had seen significant run-out I would have quite right here. The raised face against the flange could be way off, and that face is one of those "air interface only" surfaces. The measured run-out in this setup was only 0.0003". It cleaned up to less than 0.0001

With the adapter properly mounted, the indication against the edge shown here was again 0.0003. I could have created that run-out myself from the previous clean-up action. I lightly cleaned-up both the faces here to less than 0.0001

The back view of the 5-C chuck shows the inside "air interface" in the center recession and the real interface which is the outside face perimeter. On the inside edge of the flange (pointing inward) you can see the four setscrews that do the final very exact adjustment for centering the chuck on the adapter plate. This is one tool I have NOT totally disassembled to clean and re-lubricate. There is only machine oil on this chuck, but I can't say how later shipments will be preserved.

I made little "pip" marks on the flange and adapter so that I can get them back together in the same relationship next time. The head does not have a mark in this picture because I considered the setscrews allow for adjustment. However, there is a relationship between the the two faces, so I will add another mark, just to be sure.

Here is where I measured T.I.R. when setting up the chuck. I don't have an inside indicator, but since the chuck is machined in one piece and must have been turned in one setup, this is very accurate. I easily got it down to LESS than 0.0001 T.I.R.

This is one of the four set screws to adjust for accuracy. Actually this was the LAST thing I did. I just left these set screws loose, snugged up the mounting screws slightly and used extremely light taps with a plastic mallet to adjust run-out. Then I played with all the bolts to tighten everything up. I did not, and could not use my hand on the chuck to rotate the chuck for these measurements. I went into the drive (belt) side of the lathe head and rotated from there.

The collet wrench can be used in any hole. It rotates a threaded ring inside the head. I don't see any reason why one socket hole will have any advantage over another. The collet is prevented from turning in the chuck head by a pin, so the threading action is simply drawing the collet directly back into the head.

With a collet chuck of this accuracy, I feel it is almost a sacrilege to use cheap 5-C collets. But that is what I have. These are from Enco and of course are made in China. They are only about $5.55 apiece. I have heard of 5-C's as expensive as $35.00 or more each. My plan is the same as end mills. I'll buy a cheap set to begin, then when I find a problem or need a replacement, I'll buy higher quality in the sizes I use. Sounds reasonable to me.

This is a piece of 3/8 TPG rod I bought for my CNC machine project. It is probably the most accurate rod I currently have in shop. The T.I.R here was IMMEASURABLE! A little wiggle on the pointer. Gads! I don't think it gets much better than this. I check it six times to make sure the indicator wasn't broken.

I am about to make the first cut with the new toy. There is almost nothing better to accurately hold stock than a collet. There are many sizes and shapes of 5-C collets in the catalogs. If you are looking for the best in machining accuracy, this is the way to go.

Here is an overall view of the chuck on the lathe.