[Jon Anderson]

Had a brochure years ago for a company that made worm wheels cut to use
standard threaded rod for the worm. Can't find it now. I might well end
up making my own, but at least want to see (if they're still around)
what an off the shelf worm wheel would cost.

Anyone run across, and remember the name of this outfit?


Jon

[Tim Wescott]

On Fri, 02 Dec 2011 08:47:33 -0800, Jon Anderson wrote:

Had a brochure years ago for a company that made worm wheels cut to use
standard threaded rod for the worm. Can't find it now. I might well end
up making my own, but at least want to see (if they're still around)
what an off the shelf worm wheel would cost.

Anyone run across, and remember the name of this outfit?

I'm guessing he

I think that such an assembly would be even more inefficient than a worm
drive. Additionally, it seems that getting proper mesh would be
problematic: a worm gear will have a sort of flat-ish spot that'd give
you a nice broad optimum, while a V-cut would require that you get
everything just right to work. Moreover, the V-cut would tend to always
want to push the gears apart, to a greater extent than a normal worm gear
tooth profile -- put that together with the extra need for accuracy, and
it'd be difficult to keep your assembly in tune.

It sounds like one of those deals that's just too good to be true.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

[Ed Huntress]

On Fri, 02 Dec 2011 12:38:33 -0600, Tim Wescott
wrote:

On Fri, 02 Dec 2011 08:47:33 -0800, Jon Anderson wrote:

Had a brochure years ago for a company that made worm wheels cut to use
standard threaded rod for the worm. Can't find it now. I might well end
up making my own, but at least want to see (if they're still around)
what an off the shelf worm wheel would cost.

Anyone run across, and remember the name of this outfit?

I'm guessing he

I think that such an assembly would be even more inefficient than a worm
drive. Additionally, it seems that getting proper mesh would be
problematic: a worm gear will have a sort of flat-ish spot that'd give
you a nice broad optimum, while a V-cut would require that you get
everything just right to work. Moreover, the V-cut would tend to always
want to push the gears apart, to a greater extent than a normal worm gear
tooth profile -- put that together with the extra need for accuracy, and
it'd be difficult to keep your assembly in tune.

It sounds like one of those deals that's just too good to be true.


I've made several of these things on my lathe with the milling
attachment. One of them is in use right now, on my fishing-rod
rotisserie, which I use for getting the layer of epoxy evenly
distributed on guide windings.

If you're in need of a light-duty worm gear, they work fine. You
chuck an ordinary thread tap in the lathe spindle. First turn a blank
for the gear in the lathe, drilling and boring a hole in the center
for a temporary spindle.

I've used a bolt for the spindle, polishing it up a bit on the lathe.
Chuck the spindle with gear blank in the milling attachment vise (you
can clamp it in a toolpost if you don't have a milling attachment).
Feed the edge of the gear into the rotating tap until it starts to
cut. It will self-feed.

If' you're lucky, it will cut clean, or nearly so, all the way around
the blank. If it's a little rough, keep feeding the blank into the tap
until you get a clean cut. You may have to turn a little bit off of
the blank's periphery to get a clean cut all the way around.

That's all there is to it. If you need an exact number of teeth on the
gear, forget about it. d8-)

--
Ed Huntress

[Jon Anderson]

On 12/2/2011 10:38 AM, Tim Wescott wrote:

I think that such an assembly would be even more inefficient than a worm
drive.

You are right. But for my ultra light and infrequent application, not an
issue.


Jon

[Lloyd E. Sponenburgh[_3_]]

Jon Anderson fired this volley in
:

Had a brochure years ago for a company that made worm wheels cut to use
standard threaded rod for the worm. Can't find it now. I might well end
up making my own, but at least want to see (if they're still around)
what an off the shelf worm wheel would cost.

Anyone run across, and remember the name of this outfit?


Jon


Jon, I don't remember the company, but I saw a neat demo either here or
on CNCzone that showed a guy making such wheels.

He pivoted the blank on a shaft on a vertical member in his mill vise,
then used a common tap of the requisite thread as a milling tool. He
simply advanced the tap sideways into the edge of the blank a few thou,
and let it cut all the way around, then advanced again, etc., until the
profile was cut full depth.

It was simple, elegant, and worked perfectly.

LLoyd

[Jon Anderson]

On 12/2/2011 10:40 AM, Lloyd E. Sponenburgh wrote:

He pivoted the blank on a shaft on a vertical member in his mill vise,
then used a common tap of the requisite thread as a milling tool. He
simply advanced the tap sideways into the edge of the blank a few thou,
and let it cut all the way around, then advanced again, etc., until the
profile was cut full depth.

Yeah, that's the technique I'll be using if I end up making it.

The intended use btw, is a vertical column for my macro photography rig.
I'm big into recycling what I got, and I happen to have a Sherline Z slide.
I'll use a different screw with a RH thread. The worm wheel will have a
knob at the end of it's shaft and when this knob is turned, it'll act
like a rack and pinion. When this shaft is locked, I can use the screw
for fine adjustment. Loads will be very light and use rather infrequent
really. I hesitated to mention intended application as that just invites
a lot of input on other ways to do things. I have a lot of options and I
know what they all are. But I like to do things a bit different. I know
what I'm doing and why I'm doing it and not really open to debate.
(however, if someone has a focus block like the vertical one pictured
below they would sell REALLY cheap, I'd jump on that!)

Overall, this is more or less what I'm building:
http://www.photomacrography.net/forum/viewtopic.php?t=8247

Except I'm using linear slides instead of expensive focusing blocks for
linear movement. And the slide my bellows/camera mounts to will be
driven by stepper motor via a dedicated and purpose built controller.


Jon

[[email protected]]

On Dec 2, 2:23*pm, Jon Anderson wrote:
I hesitated to mention intended application as that just invites
a lot of input on other ways to do things.
Jon

Not so much giving you an input on other ways...............Well yes
it is, but then..........

Can you not use a regular worm gear and Acme threaded rod with the
same pitch?

Dan

[Jon Anderson]

On 12/2/2011 2:12 PM, wrote:

Can you not use a regular worm gear and Acme threaded rod with the
same pitch?


Don't see why not, but I'm looking to either use as much as I can from
my scrap and parts bins, or buy something that'll do the job. If I have
to go buy acme screw stock and a worm wheel and add labor to that, I'm
getting close to the tipping point of just buying a focusing block.
If I could get a post mount focus block for $50, I'd just do that, but
cheapest I've seen one on ebay is around $90.
Spend money and save labor or spend labor and save money. Don't want to
do both... And, I do like the idea of doing something a bit different...


Jon

[[email protected]]

On Fri, 02 Dec 2011 15:19:47 -0800, Jon Anderson
wrote:

On 12/2/2011 2:12 PM, wrote:

Can you not use a regular worm gear and Acme threaded rod with the
same pitch?


Don't see why not, but I'm looking to either use as much as I can from
my scrap and parts bins, or buy something that'll do the job. If I have
to go buy acme screw stock and a worm wheel and add labor to that, I'm
getting close to the tipping point of just buying a focusing block.
If I could get a post mount focus block for $50, I'd just do that, but
cheapest I've seen one on ebay is around $90.
Spend money and save labor or spend labor and save money. Don't want to
do both... And, I do like the idea of doing something a bit different...


Jon

Greetings Jon,
I have made for myself several worms and wormgears using the tap
method. If you decide to go this route use a high spiral tap if you
have one. These taps stay engaged in the work constantly. I have had
no trouble getting the exact numbers of teeth I wanted. I have used
3/8-16, 5/16-18, M8 x 1.25, and other taps of similar size but
different pitches to cut the wheels. I just hold the tap shank in a
collet. The wormgears (AKA wormwheels) I held with a screw screwed
into a piece of steel stock held in a toolholder on the Aloris
toolpost. Making the gears out of brass is easy and I bet you could
make your first one in less than 1/2 hour.
Eric

[axolotl[_2_]]

On 12/2/2011 11:47 AM, Jon Anderson wrote:
Had a brochure years ago for a company that made worm wheels cut to use
standard threaded rod for the worm. Can't find it now. I might well end
up making my own, but at least want to see (if they're still around)
what an off the shelf worm wheel would cost.

Anyone run across, and remember the name of this outfit?


Jon


Here is Chris Heapy's procedu

http://www.astronomiainumbria.org/advanced_internet_files/meccanica/easyweb.easynet.co.uk/_chrish/worms.htm


Kevin Gallimore

[Martin Eastburn]

V ? Most threaded rod is a V.

I think you wanted the square based thread used on lathes and mills.
A flat end screw rides in it or a half nut clamps on them.

Either a square thread or an Acme screw thread (most common).

http://www.techno-isel.com/LMC/Products.htm#SCREWS

MSCdirect also has screws.

On 12/2/2011 10:47 AM, Jon Anderson wrote:
Had a brochure years ago for a company that made worm wheels cut to use
standard threaded rod for the worm. Can't find it now. I might well end
up making my own, but at least want to see (if they're still around)
what an off the shelf worm wheel would cost.

Anyone run across, and remember the name of this outfit?


Jon

[Jon Anderson]

On 12/2/2011 9:25 PM, Martin Eastburn wrote:

I think you wanted the square based thread used on lathes and mills.
A flat end screw rides in it or a half nut clamps on them.

No, I want a V based worm. As mentioned, I know what I want and why I
want it. It's a very low stress application. I like designing things
that work a bit different. Also known as, I enjoy being a weirdo
sometimes... G

Actually I'd use acme rod if I had any suitable acme taps laying around.
But the cutting of light duty vee thread worms is not all that uncommon.
There is a fellow not too far from me that makes tracking mounts for
telescopes. He uses V thread based worms. If it's good enough for
telescope use, it's good enough for me!


Jon