VN16 Rebuild

[Cal Haines]

My Van Norman No. 16 mill has been waiting for its turn and I have finally gotten started on the rebuild. The bearings in the gearbox and cutter-head are shot and it's clear that I need to go through the table and most of the components in the knee before the old beast is ready for service.

Before I spend a lot of time posting and take up a space on the server, I want to make sure that there is interest in the subject. I'm planning on an illustrated, step-by-step series as I go through the machine, along the lines of Harry Beckley's epic posts over in the Monarch forum. I'll try to make it interesting for anyone interested in machine tool repair.

So far I have the gearbox torn apart and I would have liked to have known at the start what I have learned so far. Maybe I can leave something here so that the next guy will have a leg up.

So, who wants to play along?

Cal

 

[JacobS]

That sounds good. There's quite a bit on VN interest on here. I know the knee on my 22 is full of expensive parts and unfortunately I'm missing a few. It'd be nice to archive the rebuild if you're willing to write it up.

 

[sealark37]

Van Norman 12 & 16

Hey Cal- I, too, have a VN#16. Mine is in good shape, but I would very much enjoy watching a tear-down and rebuild. I will be waiting for your first installment. Regards, Clark

 

[Ferrous Antiquos]

My recently acquired 1956 vintage 16-S seems to be in pretty good working order, but you can count me in as an interested bystander. Prior to this I owned a #6, a #22-LU, and a couple of #12s, seems like a lot of the basics probably apply to these and other models as well.

 

[JBishop]

Cal, count me in also, have the 16's younger brother, the 1RQ-3-28. Jim.

 

[Cal Haines]

Introduction

The machine I’m rebuilding is a Van Norman No. 16, s/n 5310. A tags indicates that its finish meets “National Procurement” standards. I have no idea when it was built. Anyone know?

The No. 16 has three larger siblings: the 16M, 16L and 16S. All three have a bigger column with a larger table and work envelope. The No. 16 is most similar to the 16M; they use the same ram and 9-speed gearbox driven by dual belts; I like to think of my No. 16 as a 16M Junior. The 16L and 16S share a ram with a 2-speed gearbox driven by a single belt; 4-step pulleys are used to provide a total of 8 speeds. The 16S is probably the nicest of the four machines, with a power-fed quill. The 16M is the heavy weight of the family; it’s the only one with a 3HP motor, the rest have a 2HP motor. The 16L is the “Plain Jane” of the 16 series, but has the 16M’s heavy-duty cutter-head. All four machines have a Van Norman ‘C’ series spindle which accepts collets with a maximum capacity of 5/8” and horizontal milling arbors up to 1¼”.

My machine has a universal table, which means that the table can pivot right or left up to 45 degrees for special milling operations, such as helical milling. Universal tables were available on the larger 16-series machines as well.

 

[Mike C.]

"A tags indicates that its finish meets “National Procurement” standards. I have no idea when it was built. Anyone know?"

That means WWII, like a huge number of the VN machines. I think John Kasunuch's site has the serial number date list that includes the 16. My 12 is a 1942.

 

[Cal Haines]

... I think John Kasunuch's site has the serial number date list that includes the 16. ...

Thanks, Mike. I had forgotten about that. According to the table at John's site, Kasunich - Serial Numbers, my machine was built in 1952; so it’s Korean War vintage. Elsewhere on his site he indicates that a total of 1017 16-series millers were built between 1947 and 1961.

Cal

 

[Cal Haines]

REMOVING THE CUTTER-HEAD

We started by removing the cutter-head. It’s held in place by three T-bolts that run in radial slots in the ram casting. The two forward bolts are longer and have spring-loaded tubular nuts. I’m missing one of the springs and will want to replace it at some point.

The rear T-bolt is shorter and hides between the rear of the cutter-head and the ram. Mine has an odd-sized nut which seems to take a 25/32” wrench. I have more wrenches that anyone else I know, but not a 25/32”; a 20mm wrench did the job. I’ll be replacing the odd-sized nut when I put the cutter-head back on. The threads on the rear T-bolt were visibly stretched. I haven’t decided yet if I will make a new one.

The cutter-head was easily removed by placing it in the vertical position and blocking it up with 2x4 blocks. (For added security, I recommend using a couple of 1x2 blocks nailed to a 2x6 instead.) We raised the knee to support the cutter-head and removed the forward (tubular) nuts. The rear nut is trapped between the cutter-head and the ram and can’t be removed without pulling the cutter-head off of the ram. We moved the table to the left as the rear nut was backed off and the cutter-head came free with ease. The cutter-head weighs almost 70 pounds. One man can pick it up, but I would not suggest trying to remove it without supporting it in some fashion.

REMOVING THE OVER-ARM ARBOR SUPPORT

The over-arm arbor support consists of a 2-3/8” diameter by 36” solid bar with an aluminum casting clamped to the end. The casting contains a bearing assembly for the pilot on the end of some Van Norman 'C' series arbors. The bar and bearing assembly weigh about 55 pounds but I find it too unwieldy to handle by myself; you are advised to get help or appropriate rigging when removing it.

It looked like things would be easier if we got the over-arm arbor support out of the way. It hasn’t moved in many years and was frozen in place. After loosening the two clamps, we managed to free up the support by liberal application of a rubberized dead-blow hammer and WD-40. We started by striking the aluminum body of the arbor pilot bearing assembly, hitting alternate sides until the over-arm was rotating with relative ease. Then we changed to striking the end of the bar and working it in and out until it was free.

The hole in the ram for the over-arm bar is bored to a close fit to the bar for the first 6” and for about 4” around the clamp on the left side of the ram. Between the two bored areas and for the rear 8” the casting core is was larger than the bar and the casting does not contact the bar in those areas.

Cal

 

[Cal Haines]

Belt Drive

BELT DRIVE

The drive belt guard was removed to gain access to the gearbox. It mounts on three studs and is held in place with nuts and washers. The gearbox is driven by a pair of V-belts. I was surprised to find that the motor is equipped with a double pulley for two different belt ratios, whereas the parts drawing shows a single pulley.

The input shaft to the gearbox, however, has a single-ratio pulley, so the only way to make use of the dual pulley on the motor is to pull it from the shaft and flip it over. Also odd about my machine is the fact that it has the same shifter data plate as a 16M, which has dual ratio, dual belt pulleys on both the motor and the gearbox. Since the input shaft to the gearbox on the No. 16 and the 16M are the same (part number 16-1049), it should be possible to put a dual ratio pulley on the input shaft, despite the fact that it isn’t long enough to go all the way through the pulley.

Here's a scan of the shifter data plate from the manual. Mine is so battered and faded that I can't really read it:

We discovered that someone had been greasing the motor without removing the plug at the bottom of the bearing, perhaps because they were too lazy to remove the belt cover to get access to the plug. A large mass off excess grease had accumulated on the right end of the motor.

To remove the belts, we loosened the two SHCSs on the right side of the ram and drove the motor forward with a wooden block and hammer. The V-belts are A section, about 42” around the outside; I guess that makes them about an A40 trade size. Mine were marked “Truflex 2420”.

Cal

 

[Reeltor]

2-HP motor?

Cal,

May be a little off topic, are you saying that that big vintage motor on top of your mill is a 2hp? Did the criteria for measuring HP change over the years?

 

[Cal Haines]

Mike,

Yep, it's only a 2HP. It's actually 1" larger in diameter than the 7.5HP I use as an RPC idler (although its not as long). I don't know if the rating criteria changed, or if they just got better at making motors...

Cal

 

[Cal Haines]

Gearbox Top Cover Removal & Initial Assessment

REMOVING THE GEARBOX TOP COVER AND SHIFT LEVERS

The top cover of the gearbox carries the shifter for the gearing. It is secured with 5 socket head cap screws. Mine was also stuck down to the gasket with some sort of gasket sealer. We wasted some time trying to remove the forward clamp for the over-arm support bar but discovered that it is not necessary to remove the clamp or handle. Nor is it necessary to remove the small, rectangular cover behind the shaft of the shifter, to remove the main cover.

We broke the cover free by tapping upwards on the right side (which overhangs the ram casting) with a brass hammer. A pair of pry bars was then used to lift the cover upwards, freeing the gears that control the shift forks, and coaxing the cover free.


INITIAL ASSESSMENT

The machines serial number was found stamped on the right side of the gearbox, near the top cover and in front of the mounting stud for the belt guard. It matched the serial number on the data plate on the left side of the column.

The inside of the gearbox was disgusting! It was full of an odd-smelling substance the color and consistency of baby poop. We pulled the magnetic drain plug on the bottom of the ram (it’s located 3½” from the front and takes a 3/8” Allen key) and, over time, about a gallon of the vile substance oozed out of the gearbox.

All three shafts had a huge amount of end play, well over 1/8” for all three. All three sets of bearings are Timken tapered roller bearings. There was so much end play in the front/output shaft that some of the rollers had managed to escape from the bearing. At least two of the bearing roller cages had been destroyed by running the machine with loose bearings. The pulley end of the input shaft had rubbed against the end-plate and had significant wear. But none of the rollers were chewed up as you would expect for such excessive end play. I can only assume that the bearings were not properly adjusted when they were installed.

Despite the excessive end-play, the only evidence of serious internal wear was on the small gear [16-1052] on the intermediate shaft. It shows evidence of having run at about 75% engagement with the center gear on the input shaft. The gear pair to the right also shows evidence of running at about 75% engagement. It appears that whoever had the top cover off last failed to properly time the rear shifter fork to the handle.

Cal

 

[beckley23]

I've been into some nasty stuff, but that stinks just looking at it. Have you figured out what it is?
Looks like you're going to some fun, along with some surprises.
Harry

 

[locoguy]

Might I suggest that the improper gear alignment may have occurred because of the excessive end-play on the bearings and gear shafts, not improper timing of the shifting levers? Same thing happened on a smaller VN that I own.

Good luck with the resto.

Looks like some moisture got into the gear box.

Locoguy

 

[Ferrous Antiquos]

Gearhead studs

Cal,

When you took off the gearhead, can the T-bolts be removed easily from the ram face?
Mine is held on by 4 studs, all with nuts (M22 wrench worked great). The back bottom stud was butchered off and needs replacement.

 

[mark thomas]

I will enjoy the restoration. As you know, I have a 16S.

Btw, you wrote:

"All four machines have a Van Norman ‘C’ series spindle.."

But the 16 was also available with 30 taper.

 

[Andy FitzGibbon]

I will enjoy the restoration. As you know, I have a 16S.

Btw, you wrote:

"All four machines have a Van Norman ‘C’ series spindle.."

But the 16 was also available with 30 taper.

This comes from fuzzy memories, but I believe that in the later years all of the 16 series machines had switched over to NMTB tapers. The 16S I have definitely seen with a 30 taper spindle, and I'm pretty sure I have seen another in the series (16M or 16L) with a 40 taper spindle. I bet the "C" taper was still available as a special order, though.
Does anyone know if the "plain" 16 (no suffix) was made concurrently with the 16S, L, and M? I was always under the impression that the suffixed models were an evolution of the original machine. The 16 series was made for quite a few years.
Andy

 

[mark thomas]

This comes from fuzzy memories, but I believe that in the later years all of the 16 series machines had switched over to NMTB tapers. The 16S I have definitely seen with a 30 taper spindle, and I'm pretty sure I have seen another in the series (16M or 16L) with a 40 taper spindle. I bet the "C" taper was still available as a special order, though.
Does anyone know if the "plain" 16 (no suffix) was made concurrently with the 16S, L, and M? I was always under the impression that the suffixed models were an evolution of the original machine. The 16 series was made for quite a few years.
Andy

If this website is accurate:

Van Norman Milling Machine Serial Numbers and Dates

Then the 16 was made 1947 thru 1955, and the 16S, 16L, and 16M made concurrently from 1955 thru 1960. Since the main column casting changed for the suffix models, it seems like it's an evolution and I would doubt plain and suffix models were made concurrently, except briefly during transition.

My 1955 16S is "C" taper, which might have been more common in this first year of production. I know the 16S also came in 30 taper version, another PM member has one. I don't believe the 16S spindle is large enough to accommodate 40 taper however. But without quill, the M and L model might have.

Slight tangent... based on serial numbers on the website, the production quantities were:

16 : 554
16L: 93
16M: 88
16S: 229

I'm skeptical of that however. The 16S seems a lot more rare than these numbers would suggest.

 

[Cal Haines]

Cal and the Oobleck

I've been into some nasty stuff, but that stinks just looking at it. Have you figured out what it is? …

Harry,

I don’t know what it is. It has a mild petroleum smell, it’s thick as molasses, feels like oil, and the stuff that I drained out hasn’t really separated. (I’ve got it sitting in a jug, waiting to go to hazardous waste collection—I just hope they don’t cart me off to Area 51 for interrogation when I bring it in.) The stuff reminds me of the children's story Bartholomew and the Oobleck, except that Oobleck was black…

Despite the rust color, nothing inside the gearbox is rusty. There is a little bit of corrosion on one of the splined shafts, where some moisture may have gotten trapped, but that’s it; the surfaces that were in direct contact with the Oobleck aren’t rusted. If I dip a probe into the top of the jug, it comes out looking like regular oil.

There’s more Oobleck inside the cutter-head, only it’s thicker, more like soft ice cream. My buddy, who used to run screw machines, says it looks like the stuff that would accumulate in the bottom of the cutting oil sumps. Some sort of sulfur based oil, maybe? Maybe someone got lazy and topped the gearbox off with cutting oil?

Whatever the brown stuff is, it won’t settle out. Even the stuff in the drain pan, after I flushed it with about a pint of kerosene, won’t separate. The fact that it won't seperate suggests to me that it's NOT a machine tool gear oil, but an oil that's designed to work with a filter. A previous owner may have been of the "Ahl is Ahl" (Oil is Oil) camp, and used motor oil. Whatever the case, it sure looks like Eisenhower was president the last time the oil was changed...

Might I suggest that the improper gear alignment may have occurred because of the excessive end-play on the bearings and gear shafts, not improper timing of the shifting levers? Same thing happened on a smaller VN that I own. …

I guess that’s possible. However, the front shaft had the most end-play of all and it seemed to mesh well enough with the intermediate shaft. When I was looking at it, it appeared that moving the shifter rack by one tooth would correct the misalignment.

When you took off the gearhead, can the T-bolts be removed easily from the ram face?
Mine is held on by 4 studs, all with nuts (M22 wrench worked great). The back bottom stud was butchered off and needs replacement.

You must have a 16L/16M/16S? I don’t know for sure but it appears from the parts drawing that the T-bolts come out of the side of the ram casting, like they do on my plain No. 16. The No. 16 has three 90-degree T-slots arcs with a hole at one end for removing the T-bolt. The diagrams for the 16L/16M/16S show a single, 360 degree slot, but I don’t see a hole for removing the bolt head. The diagrams show a standard-looking T-bolt and I can’t imagine how else they could be removed, if not from the side. I’m comfortable in saying that it’s not a big deal to remove the cutter-head and have a look. The method I used, above, should work well for either the 16M or 16L; the 16S cutter-head looks pretty top heavy, so it will probably be a good idea to have an assistant steady it as it is removed. And the 16S cutter head has got to weight well north of 100 pounds.

This brings up something interesting: The Van Norman part number for the No. 16 ram is 16-1025; the call out appears twice on plate #2 of the No. 16 manual, with drawings showing the two sides of the ram. The manual for the 16L/16M/16S has a similar pair of diagrams on plate #3 and calls out the ram as 16-1025 for the left side view, but 16-750 for the right side. The 16M ram drawing with the 16-1025 callout is clearly not the same as that of the No. 16: it shows the circular mounting slot for the cutter-head. Anyway, I was wrong when I said, above, that the No 16 and the 16M use the same ram. The 16M has a longer ram, but the gearbox components are mostly the same, part number by part number.

... you wrote: "All four machines have a Van Norman ‘C’ series spindle.."

But the 16 was also available with 30 taper.

Thanks for the correction. My manual does show that the 16M was available with 30 taper or ‘C’ shank spindles; I guess I’m suffering from brain fade…

Have you seen any of the other models listed in VN literature with 30 taper, or do you suppose it was a special order option?

Mark & Andy,

Good information on the serial numbers, etc. I had missed the fact that the No. 16 came first, with a transition to 16L/16M/16S in 1955. I’ll have to update my summary for the PDF version of my rebuild log.

Looking at John's serial number table, it looks like each base model of miller had serial numbers starting around 5000. When a variation on the model was added to the line, they apparently dropped the starting serial number by 1000 (or more) for each new version. I know that Monarch would assign serial numbers when a machine was ordered. If the order was cancelled, the serial number was not reused, so you can't tell how many machines were actually built by subtracting serial numbers. Van Norman may have done something similar, which would explain things like the first No. 16 serial number being 5011 instead of 5001. Does anyone know the source of John's information?

Cal