Hofmann indexer?

Topics include, Machine Tools & Tooling, Precision Measuring, Materials and their Properties, Electrical discussions related to machine tools, setups, fixtures and jigs and other general discussion related to amateur machining.

Moderators: GlennW, Harold_V

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

Hofmann indexer?

Post by SteveM »

In the process of digging thru my dad's stuff, I cam across this.

It has the name Hofmann on it, and it looks like a 5C or some other collet in it.

My guess is that it is some kind of indexer, but I can't figure out how it works.

Anyone ever seen one of these?

Steve
Attachments
Hoffman(1).jpg
Hoffman(2).jpg
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: Hofmann indexer?

Post by SteveM »

Actually, the collet isn't 5C. It's quite a bit larger and it comes in from the top, with the large plate on top being the closer.

I've attached a picture with dimensions.

Anyone recognize this?
Hoffman(4).jpg
Steve
jcfx
Posts: 713
Joined: Sun Aug 09, 2009 1:24 pm
Location: NY

Re: Hofmann indexer?

Post by jcfx »

I did a quick check on Google, it's a work holder.
They're still in business ( Hofman ) and this is one -

https://www.hhw.de/en/Shop/Clamping%20e ... th_3-42_mm
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: Hofmann indexer?

Post by SteveM »

jcfx wrote:I did a quick check on Google, it's a work holder.
They're still in business ( Hofman ) and this is one -

https://www.hhw.de/en/Shop/Clamping%20e ... th_3-42_mm
Thanks. Sent them an email with pictures. We'll see what information they have.

Steve
jcfx
Posts: 713
Joined: Sun Aug 09, 2009 1:24 pm
Location: NY

Re: Hofmann indexer?

Post by jcfx »

It may be an indexer of some sort, looking closer at your pics there is a scale engrraved on
I don't see where indexing plates would go.
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: Hofmann indexer?

Post by SteveM »

I got it to work - there was a setscrew underneath that needed to be loosened. Not sure what that screw does.

Anyway, there is a circular segment that slides in a track and has a lock. You set the degrees on that and lock it in place.
20170130_215741.jpg
When you move the lever one way, it ratchets, when you move the other, it rotates until it hits the segment.

Steve
spro
Posts: 8016
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Hofmann indexer?

Post by spro »

That Hofmann is looking like a really neat indexer. I thought the swing arm had some sort of ratchet but I didn't understand how it worked until your last pic. At first I thought the right side knob lever was to lock the table but there is that threaded hole in front. I think you should be able to adjust one semicircle to allow a set "arc" of degrees between the swing and then lock it, without lifting the unit. Pretty slick.
I've seen collets which "look" like those on Ebay. I think they are used with B&S screw machines. They used to be very inexpensive.
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: Hofmann indexer?

Post by SteveM »

spro wrote:At first I thought the right side knob lever was to lock the table but there is that threaded hole in front.
That lever IS the table lock. Once you move the arm to rotate the set arc, you lock the table before performing any operations.

The whole top of the thing is actually the locking ring.

Steve
jcfx
Posts: 713
Joined: Sun Aug 09, 2009 1:24 pm
Location: NY

Re: Hofmann indexer?

Post by jcfx »

SteveM wrote: When you move the lever one way, it ratchets, when you move the other, it rotates until it hits the segment.

Steve
It's an interesting tool, I suppose that the segments you mention are like detents so the
graduated ring hits on every mark ?
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: Hofmann indexer?

Post by SteveM »

jcfx wrote:It's an interesting tool, I suppose that the segments you mention are like detents so the
graduated ring hits on every mark ?
When I said "segment", I was referring to the semicircular arc (it's 120 degrees and sits in on the left side in a channel). It just hits up against the end of the segment, which acts as a stop.

The arrows in the attached pic show the ends of the segment and the lock.
HoffmanSegment.jpg
Steve
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: Hofmann indexer?

Post by SteveM »

I found out from the manufacturer that it takes a 455E collet.

Yea, I've never heard of them either, and the manufacturer stopped producing them 25 years ago.

A google search doesn't even show up a picture of one.

The top ring that holds the collet in screws off and is threaded 110mmx2.

There are four bolt holes in the top that are 8mmx1.25 thread.

My guess is that you could mount a chuck or face plate to the top and have a nice indexer. That piece could either be threaded or simply bolt to the top with some socket head cap screws.

You could make a fixture with a 5/8" spigot on it and mount it in the collet, or grind the collet out to a larger size to hold something bigger.

It is very heavy and won't fit in a flat-rate box.

If anyone locally is interested in it, make me an offer and get it off my workbench.

Steve
Attachments
Hoffman(8).jpg
Hoffman(7)a.jpg
Post Reply