Re: [CAD_CAM_EDM_DRO] Cool Worm Gear

Hi Alan,

The tap size is the same as the worm thread so it depends on how big you
want the whole lump of worm and wheel to be. I have uploaded a couple of
files to the egroups site (link at the bottom of the message) showing one of
the worms and wheels I made using a 1/2" whitworth tap - i.e. the worm is
1/2" diameter and the wheel has 60 teeth and is a shade under 1 5/8" overall
diameter. It is best to use a fairly coarse pitch thread or the teeth get a
bit weak but there is really no constraints on the sizes you can use.

Ian
--
Ian W. Wright
Sheffield UK
www.iw63.freeserve.co.uk

----- Original Message -----
From: "Alan Marconett KM6VV" <KM6VV@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: 03 November 2000 19:35
Subject: Re: [CAD_CAM_EDM_DRO] Cool Worm Gear


> Ian,
>
> I get how the tap can hog out a gear, but what size taps are suitable
> for this? You must run the lathe slow? I can calculate the proper gear
> blank size (well, for normal gears). I want to try this!
>
> Alan
>
> Ian Wright wrote:
> >
> > Hi Smoke,
> >
> > With the tap method its quite simple - make some sort of fitting to go
in
> > place of the tool holder which will allow you to put the blank on a
vertical
> > axle, freely rotating and at centre height (in my case with the Harrison
> > lathe that involves removing the tool holder and putting a stack of
packing
> > washers on the bolt which normally holds the toolholder down. Now with
the
> > blank free to rotate in a horizontal plane, put the tap you want to use
in
> > the chuck or collet, set it going and wind the blank into it (in the 'Y'
> > crossfeed direction). Let the tap
> > cut its own teeth and, as it does so it will rotate the blank
automatically.
> > Just keep feeding the blank into the tap a bit at a time until the teeth
are
> > cut to full depth (whatever you want that to be). I normally cut them to
> > almost the full depth of the tap teeth then just tidy the top edge up
with a
> > bit of emery paper and cut a chamfer on each side to make it look
pretty.
> > That's it at its simplest. As another correspondent said, it can be
useful
> > to have first gashed the blank with the right number of teeth but it
isn't
> > really necessary if you have the size of the blank about right. This
method
> > can be quite useful if you want to make a worm and wheel with an unusual
> > ratio - one that I needed was 127:1 - not a particularly easy number to
> > divide.
> >
> > Ian
> > --
> > Ian W. Wright
> > Sheffield UK
> > www.iw63.freeserve.co.uk
> > ----- Original Message -----
> > From: "Smoke" <Smoke@...>
> > To: <CAD_CAM_EDM_DRO@egroups.com>
> > Sent: 03 November 2000 00:06
> > Subject: Re: [CAD_CAM_EDM_DRO] Cool Worm Gear
> >
> > > I wish some one would draw up both of these methods of generating
these
> > worms. No one seems to be explaining it very well.
> > >
> > > Smoke
> > >
> > >
> > >
> > > I have seen a method for cutting worm gears that looked real
interesting.
> > > The gear is held on the lathe carriage in a manner that you can index
it
> > for
> > > each tooth. The gear is heldhorizontal so it's centerline is inline
with
> > the
> > > center of the spindle. A boring bar is paced between centers with a
tool
> > > ground to the worm profile. The gear is fed across this tool using a
> > > threading operation that is the pitch of the worm, using the cross
slide
> > to
> > > set the cutting depth. This generates the correct tooth profile. I
hope
> > this
> > > explination is good enough to understand, if not I'll have to try and
draw
> > > it up.
> > >
> > >
> > > -- Greg Nuspel
> > >
> > >
> > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
> > discussion of shop built systems, for CAD, CAM, EDM, and DRO.
> > >
> > > Addresses:
> > > Post message: CAD_CAM_EDM_DRO@egroups.com
> > > Subscribe: CAD_CAM_EDM_DRO-subscribe@egroups.com
> > > Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@egroups.com
> > > List owner: CAD_CAM_EDM_DRO-owner@egroups.com, wanliker@...
> > > Moderator: jmelson@... [Moderator]
> > > URL to this page: http://www.egroups.com/group/CAD_CAM_EDM_DRO
> > > FAQ: http://www.ktmarketing.com/faq.html
> > > bill,
> > > List Manager
> > >
> > >
> >
> > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
discussion of shop built systems, for CAD, CAM, EDM, and DRO.
> >
> > Addresses:
> > Post message: CAD_CAM_EDM_DRO@egroups.com
> > Subscribe: CAD_CAM_EDM_DRO-subscribe@egroups.com
> > Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@egroups.com
> > List owner: CAD_CAM_EDM_DRO-owner@egroups.com, wanliker@...
> > Moderator: jmelson@... [Moderator]
> > URL to this page: http://www.egroups.com/group/CAD_CAM_EDM_DRO
> > FAQ: http://www.ktmarketing.com/faq.html
> > bill,
> > List Manager
>
> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
discussion of shop built systems, for CAD, CAM, EDM, and DRO.
>
> Addresses:
> Post message: CAD_CAM_EDM_DRO@egroups.com
> Subscribe: CAD_CAM_EDM_DRO-subscribe@egroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@egroups.com
> List owner: CAD_CAM_EDM_DRO-owner@egroups.com, wanliker@...
> Moderator: jmelson@... [Moderator]
> URL to this page: http://www.egroups.com/group/CAD_CAM_EDM_DRO
> FAQ: http://www.ktmarketing.com/faq.html
> bill,
> List Manager
>
>