Van Norman 7-1/2 dividing head plates

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SteveM
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Location: Wisconsin

Van Norman 7-1/2 dividing head plates

Post by SteveM »

What dividing plates did the Van Norman 7-1/2 dividing head come with?

How many plates and what holes were on each plate?

Also, what thread is the nose?

Steve
spro
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Re: Van Norman 7-1/2 dividing head plates

Post by spro »

First off, we may not be talking about the same dividing head. I cannot believe what I measured for TPI. The thread gages had become slightly tarnished so I measured what fit and it was 15 TPI. The diameter, outer diameter of the nose register- OD of threads is about 1.744" . This uses the 5V type collet. I'll recheck later and try to convince myself it is 14 or 16 TPI. but we are in the ballpark.
pete
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Re: Van Norman 7-1/2 dividing head plates

Post by pete »

I don't know anything about the Van Norman DH's. But if it's the usual 40-1 ratio then the B&S information in Machinery's HB and many other places would give you what most of heads had for plates for that ratio. They would have supplied the most used number of holes to give the best number dividing possibility's.If it isn't 40-1 then just ignore all this.
earlgo
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Re: Van Norman 7-1/2 dividing head plates

Post by earlgo »

I know this advice is not exact for a Van Norman, but I'd look at what is supplied in modern dividing heads and assume that they will produce the most commonly available indexes and replicate those. The old supplier's information is most likely what the new suppliers use as a basis for plate hole counts.
JMHO
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
applescotty
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Location: Wellsville, KS

Re: Van Norman 7-1/2 dividing head plates

Post by applescotty »

According to the Van Norman Attachments, Arbors, and Accessories catalog, the 7 1/2 Horizontal Swivel Dividing Head came with 3 plates (plus a rear mounted plate for direct indexing). Those plates provided all divisions from 1 to 50, all even divisions and multiples of 5 from 50 to 100, and some other divisions up to 360. If I'm reading the Index Table for that correctly, the three plates are:
1: 18, 24, 28, 30, 34, 37 holes
2: 38, 39, 41, 42, 43, 46 holes
3: 47, 49, 54, 58, 62, 66 holes

The Van Norman yahoo group has the index table:
https://groups.yahoo.com/neo/groups/vannorman/
It's under files, the name is "Index_Table_for_VN_Dividing_Heads.pdf". Page 3 has this information.

Scott
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: Van Norman 7-1/2 dividing head plates

Post by SteveM »

Thanks, Scotty.

We have the rear-mounted plate and the 19-37 plate.

Now I know what it's missing.

Steve
Bill Libecap
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Joined: Wed Nov 15, 2017 8:55 pm

Re: Van Norman 7-1/2 dividing head plates

Post by Bill Libecap »

I need the worm gear for mine, any one have one? I would like to buy one or at least get some details from one like the OD and any other measurements you can provide.
I need the gear part and any thing else that is extra.

Please see pictures
Thanks

Bill in Cincy
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spro
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Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Van Norman 7-1/2 dividing head plates

Post by spro »

It looks like you have the worm wheel. The worm section is 1.125" OD , ~ .85" ID, 5 TPI . Worm length 1.425"
To make sure we are talking the same head, see your pic #3 . There is a bore of 1" for the boss of the worm fixture. The fixture OD is 2" at the face.
You may already have the fixture, not shown but the # 230 or 238 is stamped in the face.
spro
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Re: Van Norman 7-1/2 dividing head plates

Post by spro »

There is more to this of course. The worm and shaft are one piece, 5.7" long. The shaft is .875" OD. IT is difficult to describe, as simple as it is. The shaft continues to the end with .275 surface extension then fine threaded for locking rings, Inner one having a collar (for trueing the play and locking collar) ending with a rectangular projection and a coarse threaded end. This follows normal practice for the vectors and drive handle.
spro
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Re: Van Norman 7-1/2 dividing head plates

Post by spro »

It is my opinion that the entire shaft began with a section of threaded Acme or similar mating thread and was cut and machined to length and milled and threaded. The evidence is there, the dimensions are there. The section was put between centers for later operations. This gets screwy but there are marks on the "worm" which are inconsistent with use. Between centers is one thing and driving/holding this part through the final machining is something else. The evidence of holding the worm is there but it doesn't matter for only the PA was in contact.
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