K&T 5-axis HMC

I am currently running a K&T HMC and after reading Skunkworks post I was wondering if anyone can tell anything about it. It has 45" travel in X,Y,& Z with a approximately 40" tilting rotary table. I can't find a model number but the Ser. No. is 85-1027-01 (if I read my scrap of paper correctly). It uses 2.250" straight shank holders. It came out of the Bendix (now Allied Signal) plant in Kansas City. The company also has an identical mill that came out of California. They have been gone through and retrofitted with new controls. They didn't spend a lot of money on the rebuild but they work fine for older machines.

Anyone know an approximate age? Why the straight shank holders? Approximate price when new? They had to be fairly sophisticated "back in the day".

At the very least, I thought the guys with ties to K&T would like to know they are still being used every day. Mine is dedicated to reworking headers for the Abrams tank power plant. I have been told the rebuilds done at Ft. Riley using the headers we do have a life of 1200 hours versus 200 hours for other rebuilds. I can look forward to being on it for awhile. I am the most junior guy in an union shop.

TIA, Jon

Interesting, the only straight shank holders I knew of were Sundstrands 2" straight shank. Supposedly when Sundstrand came out with their 2" in the '50's, they wanted something that would tool change and hold .00005 at (maybe?) a 6" gage projection. None of the taper shank connections were that good at the time.

The 2" shank was held in a collet, and used a drive key that went thru a slot in the collet to bolt into the spindle bore. There was a groove in the tool shank for tool changer grippers. The minor diameter of the groove was 1.700, so the toolholders were slightly weaker than a #40 NMTB.

One of the other advantages of the straight shank was adjustability of the tool length. The Sundstrand tools had a pull stud that also served as a length button. The pull stud had about 1" of adjustability. This was very convenient in the early NC machines with very primitive controls. It was also indispensable on the machines that had a contouring (rotary axis) spindle, as the tool length had to be hard coded into the program and could not be comped at that time.

Sundstrand also recognized the weakness of their shank, and came up with a solution. Some machines, such as the 5 axis OM4, had a second set of grippers that could tool change a 6" face mount. It still used the 2" straight shank as a pilot, but used the pull stud to seat a 6" face against the spindle nose.

I don't know why K & T used a straight shank, but those are the reasons I've been told that Sundstrand developed theirs.

K&T 5 axis machine

The machine is Milwaukeematic Model III 5 Axis. These were built from the early 60's through early 70's. The serial number suggests that it was a late model.

The straight shank tooling was a patented K&T design that was used on all Milwaukeematics until the mid 70's when 50 Taper became an option. Straight shank was discontinued in the late 70's.

When new, the machines used Bendix Dynapath controls with all hydraulic servo systems.
All had linear feedback using Inductosyn scales. Positioning accuracy of + or - .0005.

This was a high end product and sold for over $400,000 in the 60's. Most were sold to Aerospace companies making jet engine parts. Several were making parts for the Appollo program.

The machines were very heavy and structually stiff. New machines don't come close to the mass of these old work horses.

K&T Old Timer

Thanks K&TOldTimer

It is a well-built machine. Bendix in KCMO made parts for nukes. This mill does has an Army property tag with Bendix name on it also. I know some guys that worked there at that time (70s) and it was cost plus 10 so they would have bought the best.

There are also some smaller straightshank holders that must have been bought in the same lot. Not sure what they went with.

Straight shank small

The small tool holders were used on the MM Model II, MMEa, and MMEb.

we have never had a tool pull out of the spindle.. We have made some pretty heavy cuts with it. IIRC there was some sort of mechenism that was supposed to grab the back of the tool holder to keep it from pulling out. (I don't think we ever got it working.. And I could be wrong.)

You can see from this picture http://www.electronicsam.com/images/KandT/conversion/toolchangerspindle.JPG
where the tool shank was keyed.

sam

Some of the holders have a "cap" that screws in the back and there appears to be some sort of mechanism in the back of the spindle to pull them in. There is a hefty key. Some holders have a different grooves in between where the tool changer grabs on. I suppose this is for identification like mentioned on Skunkworks mill.

What was the advantage with the straight shanks? My 1939 K&T 2H uses 50 tapers.

Straight shank tooling

The main reason for the straight shank tooling was to provide random tool selection using the rings in the tool grip area. The code rings were of different diameters. 16 code rings were placed on the tool hoder and represented a binary code read by a reader containing micro switches. Tapered tool holders had no place to present code numbers that could be read by the control. Without random selection tools had to be sequentially loaded into the tool magazine. No verification was possible.

The tool retention devices were used to help keep tools from pulling out of the spindel under heavy load. Many customers disabled/revoved this feature.