K & T 2 C H -- the mill I have wanted . . .

K&T 2CH -- the mill I have wanted . . .

I am new to this forum, mostly posting in the Antique Machinery & History forum until now. Well, I am in the process of acquiring a K&T 2CH. (S/N: 7248 = 1954 -- thanks johnoder!) Right now I have to finish paying for it and bring it home -- I will post pics as soon as I can get some good ones. It is currently located in a warehouse behind tall piles of material -- I looked it over by standing on its table after climbing over all the junk around it. As soon as the way is cleared, I get to bring it home.

Over the last 25 years, in my former job of teaching manufacturing processes, I did more milling on K&T's than anything else except for Bridgeports. My first setup on a K&T was on a 2H universal, that was fully tooled, with low lead attachment (with all gears), model H dividing head, universal head (with drive gear!), slotting attachment, and rotary table. I used the slotting attachment and the dividing head to cut a 10-spline internal invoulte coupler for an old Renault transmission. The original coupling was stripped, but I had enough at the un-stripped end to make a form tool using an optical comparator. I did this job as a favor for a senior professor when I had only been in the department for about a year. It took half a day to make the tool, half a day to make the blank, and half the day to set up all the machine accessories -- I was doing this to become familiar with the machine. Then it only took an hour to make the part. The guy was delighted with the part and insisted on giving me $5 for my trouble! Later on I cut a helical gear -- no application, just for practice.

In addition to the 2H, we had a 3K, 2 or 3 K&T verticals, and a bunch of 1H’s which were to replace our five Index horizontal mills. When the decision was made to eliminate horizontal mills from the introductory machine shop course, the Indexes and the little K&T mills were all sold off. I continued giving the students exposure to horizontal mills -- every beginning student did a clean-up on the aluminum base of their air motor project with the part held in a fixture and a pos-pos carbide cutter throwing chips at the top rpm of the 2H. This was probably the highest material removal rate in the whole course!

I learned a bit of K&T lore I would share in a few more posts in this thread while I am waiting (impatiently) for my mill.

OK, here is a pic . . .



The rust seems to be pretty superficial.

I was standing on the top of the knee dovetail when I took this pic -- don't worry, I wiped my feet!

Delightful AC - thanks for sharing. That looks suspiciously like my 2CH plain, though I must admit I have yet to look at it from that perspective.
I envy you your "head hanger" on the right there.

John Oder

Sounds like some good times ahead.

Did they give you any estimate on how much time it would be before the way is cleared?
A coupla days or a coupla weeks?

AL

That's not all . . .

John,

On a shelf on the other side of the building: not only are there a few misc. arbors and the two arbor support bearings, but an arbor support brace. I do not plan on a lot of heavy hogging, but it cannot be beat for cool. The "head hanger" is also a cool deal, but I am thinking that the last owner never had the drive gear for the head, so I have "joined the club" of those with an non-usable universal head. I am much more interested in function -- making gears in particular, so I may consider using the brace and crane as "trading stock" to get the accessories I will actually use. (My jib crane will handle exchanging accessories.) I am not certain that I want to part with these items yet, so I would ask everyone not to get too excited -- unless you have an extra low lead attachment, complete with dividing head, & all gears.

Al,

I have to be patient -- this is a daughter liquidating her deceased Father's shop. She only wanted $300 for this mill, so I can wait. She still insists that it weighs less than a ton, but she set her price at scrap value, so I did not want to be too argumentative. I hope she "gets up a head of steam" and sorts the stuff out. (I am prepared to load an haul the whole 3,800#.)

AC - you probably know about this thread where WAThomas made himself a gear.

You are welcome to borrow mine if it is the right one when the time comes.

http://www.practicalmachinist.com/vb/showthread.php?t=160142&highlight=Helical+gear

John Oder

Drive gears . . .

John,

Thanks for the support -- I will probably be making a gear. I thought I had read almost every K&T thread in this forum, but I seem to have missed the one you provided the link to, so thanks again.

Am I correct that I am looking for a 32 tooth, 8 DP gear? (Note, I am hoping it will still turn up -- the seller has been notified that she gets an extra $100 if she can come up with it.) If I can get a definitive number on the helix angle and the pressure angle, I should be able to make the gear without borrowing yours. I will have the driven gear, so I can try to measure its opposite helix angle, but I would prefer the actual number the factory used if anyone knows it.

Just to put some "fuel on the fire":

I will await further comment . . .

There are differing version of the double swivel head. Mine is the plain jane whose base hangs on the overarms and clamps to the column dovetail. The first swivel is built into this base. This is a 2H head, serial 29 4575 from April 1943. It functions without issue on 12-7952 August 1956 2CH

Other versions of the double swivel head are remarkable in that the base is separate and the head itself is EXTENDABLE from that base.

My gear for the above head is 32T, 4.215 OD and if you lay the protractor head on the face of the gear, the teeth are inclined from vertical (I.E, in line with spindle axis) about 28°. This gear has integral drive lugs that fit in spindle face keyways, is pressed on a dedicated #50 NMTB shank and is emblazoned with 38337, plainly a part or assy number.

The driven gear in the head itself is identical except for details such as being opposite handed.

I.E. , this is a direct drive arrangement - no speeding up.

John Oder

Spectacular Archie! Love this kind of story, I'll be watching for updates.

I had one of those "of course" moments as I read your description.

The common error of calling a plain mill a universal, because it has a vertical attachment. A "universal" head attachment of course.

Bob

I make mistakes, but this is not one of them . . .

Bob,

How about another pic:



I guess my mill is a double universal -- triple when I put a full universal dividing head on it!

Actually the saddle was the first thing I checked after climbing onto the knee -- you can see my foot-prints on the top of the knee. (I was actually hanging up-side down with the camera at arm's length to take this pic because of the junk around the mill.)

Didn't doubt your table swings Archie, just how Reliable Tools et al manages extend the allure of a plain mill, by design or error?

Mine swings too, 2H.

Bob

What words can mean . . .

Bob,

Sorry to be defensive -- I thought I might not have been clear enough, hence the picture.

I also have to laugh at the machinery dealers and other eBay listings with their "universal" mills. Some of them are turret mills. A lot of semi-universal dividing heads are listed as "universal", a mistake that is a bit easier to make, but still deceptive.

I guess the same thing applies to machinery dealers as it does to politicians having ethics problems -- they are either:

Either way, they should be somewhere else . . .

P.S.: What is the top rpm on your 2H? My 2CH goes to 1,500 rpm. I'm told that this is the main difference between the machines. I presume that all accessories that fit one, will fit the other, not counting 2HL's, of course.

The "C" stands for "Carbide". I believe the CH mills have a bigger X axis feed screw. There are also other subtle differences, like the left-hand table end plates, but from what I've seen most accessories will interchange.
The standard range for the 2H mills was 35-1400 RPM, with optional ranges of 20-800 and 50-2000 RPM. I'm not sure if that changed for the CH mills or not.

Andy

Per catalog KT-57, the standard range for 2CH was 25 to 1500 with an added cost range of 35 to 2100

John Oder

Another difference are the tables, the CH has a larger table than the H. The column gearing does not interchange either. Overall the CH is a heavier machine, IIRC the weight tag that GE hung on my 2CH Universal is 4500 LBS.
Harry

Some K&T lore . . .

I learned a bit of K&T lore I will share while waiting for my mill to be accessible. I have seen some of this in the archives, but there are a few things I have to add. If I say something that is incorrect, please feel free to set me straight.

With regard to the direction of motor rotation, it has often been posted, the correct direction of drive motor rotation is important for proper oil pump operation. (The coolant pump will also be running backwards -- it is a gear pump and will not pump when running backwards.) This has already been discussed, but I would like to share some details I learned the easy way -- I was told by someone who learned the hard way. If the mill is one of the, non-clutch models that has a flywheel and the “clutch” lever controls a micro-switch to start & stop the motor, let me give a few details about how things work, at least on the mill I learned this on. It has been twenty-five years since I learned this so let me know if there is something missing.

K&T may have saved money by eliminating the clutch (& brake), but I believe that the main reason for the change was the addition of the spindle flywheel. I did not know that this was a common type of machine -- it was the only K&T I have seen with a flywheel, so I thought it was a rare machine.

Reason(s) for the flywheel: As carbide came into prominence, cutters had a coarser pitch. This leads to more cases when only one tooth is on the work at a time. When that tooth leaves the work, there is nothing to keep the elastic energy stored in the drive system from springing the cutter and spindle ahead of the gears driving the spindle. Not only is this noisy, but it beats the gear teeth to death. The 200# (I was told) flywheel stabilizes the spindle and keeps it turning at a uniform rotational velocity, keeping the gear teeth under load. Models that have the flywheel have an obvious cover at the back of the spindle around a foot in diameter.

With a flywheel, there would be a lot more load on the clutch when starting and on the brake when stopping. Industry wants productivity, so K&T eliminated the clutch & brake and used the high starting torque of the three-phase motor to spin things up fast. In order to bring things to a halt with equal efficiency, K&T used a system of reverse current to the motor when the stop/brake switch is triggered by the "clutch" lever. This certainly brings things to a halt rapidly, but then the whole running gear would accelerate to full rpm in the opposite direction. To avoid this K&T hung a small over-running clutch on the other end of the motor’s shaft. There is a small torque arm that is loaded by a spring and actuates a micro-switch. When the motor turns in the forward direction, the over-running clutch slips; when the motor is decelerated, nothing happens until the motor reaches zero rpm and starts to reverse. At that point, the clutch turns the torque arm against the spring ever-so-slightly, activating the microswitch, and dropping out the contactors.

What happens if you hook up the mill to the three-phase wiring to testing to test if it turns the right way?
The main solution that a big, modern operation uses is a strict definition of L1, L2, & L3, but smaller operations should take care to remove the sensing assembly until proper direction of rotation is established. There are probably a few missing details, but hopefully this gives you the general idea . . .

JOHN..... Is my 2hl a lighter duty machine?


John Fahnestock

Is my 2hl a lighter duty machine?

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Yessir John. 2 7/8 overarms compared to 3 5/8" and 2750 lbs compared to 3720 (2HL plain compared to 2H plain). Your 2HL also has 40 taper spindle, where you could get either a 40 or 50 in a 2H, and all the 2CH were 50.

A 2CH plain, says KT-57, is 4100, and Archie's 2CH Universal is 4300

A 2HL is identical to a 1H except for table length - 2HL is 6" longer

I knew my 2CH plain was a heavy little lump

John Oder

Archie Cheda said:

P.S.: What is the top rpm on your 2H? My 2CH goes to 1,500 rpm. I'm told that this is the main difference between the machines. I presume that all accessories that fit one, will fit the other, not counting 2HL's, of course.

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Sorry Archie out of town yesterday/last night, big Do-wop concert with my valentine/wife and good friends/musicians from the old days, reminiscing in the music of back seat exploration....ah boom' bopa boom' bopa boom' bopa boo-oom, why do fools fall in love...... and with wild castenet prelude, in falsetto La, la-la-la la, la-la-la la, la la la-ah, ah little darlin', boom di waddi..... man, they just don't write lyrics like that anymore. Funny, we thought it was rock n' roll back then, where'd do-wop come from?

My 2H Universal has 16 speeds, 35 to 1400RPM.
Table exclusive of end caps, 10 X 50, 50NMTB spindle.
Serial # 59-4996, on everything, including arbor supports A and B.
Tried to weigh it but it broke the bathroom scales, heavy and ....I like it like that.

Bob

What happens if you hook up the mill to the three-phase wiring to testing to test if it turns the right way?

o If you get the lucky “flip of the coin”, the motor rotates the right direction and things are fine.​

o If you are unlucky, it tears the torque arm, microswitch, & wiring to shreds. (I hope you took pictures first.)​

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There are PHASE ROTATION TESTER to check that things are wired correctly when you can't just turn it on to check. Maybe you know a electrician or industrial maintance man who would loan you one.

Nice Find by the way.