Van Norman dividing head

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

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Glenn Brooks
Posts: 2930
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: Van Norman dividing head

Post by Glenn Brooks »

Earlgo and Pete, thanks much for your suggestions and background on the ER series! I’ll definitely look into this ER thing again. I didn’t realize you could get an Er chuck with MT3, but makes sense to look at that route.

One update. I remeasured the taper at a slightly different set of locations, and came up with 1.300” and 1.100”, which works out to slightly under 1:50 with a 4.09” taper length. Still doesn’t match any commonly published taper- but I need to remeasure and verify length again tomorrow.

Also, I did find a mention of “old style 10” DH” and “new style 10” DH” in the links BIgDumbDinosaur sent. And a DH 10 patent date of 1941, with mention of this style DH as early as 1935. So I think this unit is a mid to late 30’s unit. There were lots of proprietary collet sets made in that era, most of which have long since disappeared. And the 2” -5 TPI thread on the nose is definitely a pre WW2 VN thread style.

Anyway, I’ve got 4 existing sets of collets in the shop and an ever increasing managery of odd sizes that have walked in the door with my old antique machine tools. R8, 5C,3C, VN C -similar size to 3c, but of course incompatible , 3A, some off the wall things with AD stamped on them. And a bunch of orphans. Probably no different than anyone else in the hobby. So, ive been a bit hesitant to buy an additional collet series.

Also, Turning tapers that fit correctly is not something I’ve had great success with- so my first inclination was to score something easy, off eBay. But now, the No 10 seems to be at the top of the no find list- at least cheap, old originals. Plus, there’s still a good chance if I buy one, it won’t work, as the numbers still aren’t quite right.

Anyway, my original goal is to restore my old VN 12 universal miller with original tooling, so probably still worth an effort to see if this is doable. In addition to the ER collet, One other option is to make an adaptor sleeve for the DH that fits my existing VN C collets, that the mill uses. I do have a complete set of NOS VN C collets that fit the mill. All in all it sounds like making the MT3 ER collet chuck is a vastly more effective route. Having fallen into the restoration black hole I will undoubtedly try the more difficult route first, just to see if it will work...or even do both...:)

Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
pete
Posts: 2518
Joined: Tue Feb 10, 2009 6:04 am

Re: Van Norman dividing head

Post by pete »

Everyone has different opinions Glenn and this is just mine. A MT ER collet chuck for a mill spindle with that taper then an obvious yes, for a lathe? Ok it's quick to set up and completely usable with fairly short cut to length parts. But I place a high value on a lathes hollow spindle. And wouldn't give it up without good reason. If it will fit through that spindle then a spindle nose mounted ER collet chuck can hold and do long parts or multiple parts machined and parted off the same length of bar stock just like any 3 or 4 jaw can. Something maybe worth considering anyway. My lathe has an MT 4 so that 40 size goes just barely above what my spindle through hole is. I kept the not great ER 32 and MT 3 chuck my old X2 sized mill used and it also fits my lathes tail stock. One other item I forgot to mention about ER's, there far better at holding drills than anything else I've ever used including an Albrecht. It's an extremely rigid method and the drills even sound a bit different as there cutting. Again not fast to swap out for different drill sizes, but if your trying for decent location accuracy and hole size they really work well. ER's have some pretty high torque requirements for tool holding, about 100 ft. lbs for the largest ER 32 collet and 130 ft. lbs for the biggest 40. For tool holding those are maximum numbers and as the collet hole size drops so do those torque numbers. When used for part holding those numbers can obviously be far less and still work just fine.

And if you've never used them there is a trick to inserting the collet into the nut before it's screwed onto the chucks threads. https://www.google.com/search?client=fi ... Tj77u4CA31 he's not clearly showing it because on the better ones the collet needs to go into the nut on a slight angle until the nuts eccentric ring grabs one side of the groove in the collet, then the collet gets snapped over so the whole groove at the upper end of the collet is then grabbed by that ring inside the nut. Removal is just the reverse of that.That ring is used to both help compress the collet down to the tool shank or part size as it pushes the collet into the chucks taper. It's also used to release the collet on whatever it's holding or fully extract the collet out of the chuck taper. But I have zero idea how he's saying the 7 ER 40's he's showing cover the full holding range. Yes they'll probably hold whatever you need in a mill, but a full set is 24 collets. https://www.maritool.com/Collets-ER-Col ... _info.html Some time ago I think a post on here did mention that a set of metric ER's covers the same holding range but I think they can do so using 2 less collets? I'm unsure of that detail though. I don't think in metric so glancing at the collets marked imperial size is worth the extra 2 collets to me anyway.
Glenn Brooks
Posts: 2930
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: Van Norman dividing head

Post by Glenn Brooks »

Pete, very interesting about holding drills, and fitting the nut and collet. I was on the verge of buying a set of ER32 two years ago now, then stumbled across a set of really high grade NOS US made 5c collets at an estate sale. Think I paid $25 for the complete set in a wooden box. So that sort of ended my collet quest - until recently. Of course mounting in the tailstock is a real asset, which I had not thought about.

BTW, I have a very nice MT 4 dead center that I have no use for. It’s left over from. My old Standard Modern big iron lathe. I think it has a carbide tip. Doesn’t fit anything I have now. Happy to send it to you, if you can use it. PM your address

Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
earlgo
Posts: 1794
Joined: Sat Jan 29, 2011 11:38 am
Location: NE Ohio

Re: Van Norman dividing head

Post by earlgo »

Pete is right about the #3MT ER chuck in a lathe, it requires short parts or stock. Little Machine shop sells the #3MT ER chuck and also an ER chuck that requires a spindle adapter but leaves the lathe bore open. https://littlemachineshop.com/products/ ... &category= If I weren't so impecunious I would have bought one of them. But I spent far more time fiddling with a cheap chinese #3MT adapter from ebay than the LMS ER chuck would have cost. :oops:

As an aside, I tried to grind the jaws of the Atlas 3 jaw chuck and it was within .004TIR at 1/2" and out .010TIR at other sizes. Tried it twice with 2 different methods and got the same result. My friend and I decided that the scroll plate was not concentric with its mounting boss. Yes we took it apart and cleaned it and there was absolutely no damage inside and all the parts fit snugly. Still a mystery to me.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
Russ Hanscom
Posts: 1955
Joined: Wed Mar 15, 2006 11:10 pm
Location: Farmington, NM

Re: Van Norman dividing head

Post by Russ Hanscom »

Matching tapers can be done without too much effort - well maybe some effort.

My process has been to take a convenient piece of stock and set up for turning between centers. Using the compound, or taper attachment if so blessed, turn a taper. smooth with abrasive cloth. Remove from the lathe and test in the socket. Adjust the taper and try again. After several iterations, you should be close. Now get the engineer's blue or a felt tip marker and determine the tight end. adjust the taper minimally until you have contact most of the length.

Once you have matched the taper, turn one for real. When I have made a match, I usually turn a bunch of blanks so I do not have to go through the discover process too often; still have a few MT 3 ones left from a batch done years ago.
earlgo
Posts: 1794
Joined: Sat Jan 29, 2011 11:38 am
Location: NE Ohio

Re: Van Norman dividing head

Post by earlgo »

A friend turned me on to a different method of setting up for a taper. He puts a relatively large (1" or so) ground cylinder in a 4 jaw and sets it center. Then he determines the taper per inch. Then he puts a DI in the compound with the DI on the CENTER line of the cylinder and adjusts the compound until the correct taper is indicated. if the TPI is .300 then when the compound traverses 1.000 inch the DI should read .150. The TPI is the included angle. NOTE: if the DI is tracking high or low on the cylinder, the taper won't be exactly correct. The cutting tool has to be on center, too.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
pete
Posts: 2518
Joined: Tue Feb 10, 2009 6:04 am

Re: Van Norman dividing head

Post by pete »

Well off the topic of identifying Glenn's taper, but since were talking about how to machine one to fit that taper as closely as possible. Without a proper bed mounted lathe taper turning attachment there's a couple of different ways. Few forum posts ever seem to mention these lathe accessories so there's probably many who don't yet know about how they work or what they can do. So maybe it's worth adding some information about them.Finding one would take some time, and I've yet to ever see one at a fairly cheap price or I'd already have one myself. Royal among a very few others made what were referred to as an off settable tail stock center. Pictures in this post link https://www.practicalmachinist.com/vb/g ... ost2112385 I've got one that works in the same way but not made by Royal that I bought a number of years ago from the UK with a MT 1 shank to fit my little Emco C5. I got forced into buying one because that tail stock is one piece and can't be off set. But mine is without most of the niceties and what your really paying for with those Royals. What I bought is still made very well and wasn't cheap but unfortunately it's still no Royal.

The type and brand shown in the link are extremely well thought out, designed, and made. They do have a proper live center, a very easy method to dial in the exact off set required, but they also have the all important hardened and ground ball tip. Off setting the tail stock center from the head stocks center results in having only a very small point where both sides of each centers 60 degree point will actually touch within the drilled 60 degree centers during each part rotation on each end of the part, so standard 60 degree centers will only have very small contact patches. In reality both head and tail stock centers should have those ball tips for the best results. They work pretty much like a simple drive shaft universal joint. It becomes a ball joint.

The Royal design also has a built in level for setting up. As the tail stocks center is being off set, the slide it operates on requires that to be exactly horizontal to the lathe bed to maintain your tail stocks C/L height. Mine doesn't have the ball tip, it only has a dead center, there's no screw adjustment for the off set amount, and no built in level. I set it's slide in a true horizontal position using an indicator on the cross slide to run the indicator tip back and forth on that tool slide and keep slightly rotating that MT shank within the tail stocks female MT until it is correct. A bit of a time consuming pita if you ask me. :-) but it does work. I'll then measure what my calculated off set on the tools center with an indicator as it's moved into position. I also use Earlgo's method of actually verifying on the already parallel machined part with an indicator what my exact taper per inch of travel is that those calculated settings say it should be as the lathe carriage travels that one inch.Then I'll final adjust until those numbers do agree. But even then no machine tool is perfect, what the lathe will then cut will still only be very close as Russ mentioned. Those unavoidable machine deflections under the cutting pressures will change things just enough that a further but minor correction is almost certain to be required.

There's many posts on various forums about just using a boring head in the tail stock to do the same, and yes it does work. Unless you were to build a live center for insertion into one of the heads boring tool bores and also add that ball tip and do the same for the head stocks dead center it won't work nearly as well as that Royal one would. But it's still a method of allowing very accurate spindle tapers to be fully machined with a lathes standard longitudinal power feed. And yes off setting the tail stock as most lathes already have as a built in feature will do the same thing. These accessories just provide a method of not needing to disturb that setting and getting it back to the exact same place. However it's done, I've still yet to see any lathe user manual mention it when showing how the tail stock can be off set about even using those ball tipped centers. Those can reduces the chances of a very poor surface finish due to the very limited support of the standard 60 degree centers. Anyone that has a lathe with a factory taper turning attachment and a built in telescoping cross slide feed screw for use with it should be very happy they do have that ability. Yes that top slide can also be used, most don't have the amount of travel required for any of the larger tapers. And like RSG's post about surface finish when using the top slide, the usual powered carriage feed is a lot easier and almost for sure gives a much better and more accurate surface finish.

Everything Russ mentioned I'd agree with 100%. But I'll add just one detail that I think is worth mentioning when turning multiples of the same tapers and using the exact same settings on the lathe while turning between centers. All your lengths of the parts your starting with should be as close to the exact same length as you can manage. Whatever center drilled into each end should again be drilled to the exact same depth as closely as you can. It's the length of the part and that distance between exactly where those male centers touch within those female centers that allow repeatability when machining the exact same taper angle each time. A few thou difference it mathematically will show only a very small difference in that taper angle, but starting with the taper blanks matching as closely as possible will make it easier and more repeatable. It's a small detail that's easy to get caught by if you didn't already know about it.
wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: Van Norman dividing head

Post by wally318 »

Glenn if you go to the Vintage machinery site they have brochures on pdf of all the old VN machines
and acc's. The vertical 10" DH is listged as a 50 taper.
But the DH you have if it is a 10" is very similar to the horizontal 7-1/2" and is listed as a VN #3 collet taper.
Maybe this helps?
There is a website Tools n gizmos they have a section there on machine tapers.
I couldn't find a taper there that was that shallow. You might give that a look
just for the sake of gaining knowledge.
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