Yes, he’s an entertaining chap, is Norm.

There’s a lot of stuff on his channel about restoring a traction engine – interesting if your only hands-on experience is with model ones.

Great video, not many left that can comprehend and set up a machine like that anymore.

Thankyou Jason!

Beautiful to watch.

It’s not really until that accelerated section near the end that we see the principle, as at normal speed the two modes of rotations of the blank, and the lift of the cutter-head, are not obvious.

There is a slightly similar technique, in principle, for cutting small gears on a single-point shaper, though I have not seen it described or done.

I noticed the adjacent machine is a big slotter. Though perhaps mainly cutting internal keyways, splines and polygons those will also produce longitudinal through-slots, and by rotating the table continually rather than by divisions, arcuate slots such as through expansion-links.

We admire and respect (and quite rightly so) the skilled craftsmen that make things, but tend to forget the equally, if not more skilled craftsmen that make the machines that allow them to make the things.

On 8 November 2025 at 15:04 ChrisLH Said:

Not to mention the ingenious chap who thought up the method and designed the machines to produce true involute gears, Mr Sam Sunderland of Keighley – just along the road from Dean, Smith and Grace famous makers of high quality lathes.

Or was it William Edwin Sunderland in 1905, British Patent 16,857?   Possibly brothers, working for the same firm, started by their father?  I can’t find a copy of the patent on the web to see who the patentee was.

Never mind craftsmen, the real glory goes to whoever did the maths.  Rack cutters are easy to make, the hard part is understanding how they generate involutes and proving it.

Rack cutters are my preferred method – no need to buy hobs or a gear-cutting machine, and well within my basic skill set.   The disadvantage is they take longer to cut gears than hobs, so buy hobs if loads of gears are wanted quickly.

I believe big gears are almost always rack cut because giant hobs are hard come by, and big gears are only made in small numbers.

Dave

SOD,

I couldn’t find anything about British patent 16,857 either. All the American patents are attributed to Sam (not Samuel) Sunderland.

On 9 November 2025 at 09:59 ChrisLH Said:

SOD,

I couldn’t find anything about British patent 16,857 either. All the American patents are attributed to Sam (not Samuel) Sunderland.

I think it’s a family. Any genealogists? An earlier Sam Sunderland was a very successful mill owner and philanthropist.  The second Sam (Mr Involute) links to the Sunderland Gear Company, which was a spin-off from an textile machine and tool company founded by John Sunderland.

I’m wondering if the mill owner had sons, one of whom, John, went into making textile tools, and had sons who became engineers.  The American Sunderlands might be brothers or cousins: same name, similar business interests.

‘Sam’ keeps popping up, possibly the family remembering clever old grand-dad.  Or just a coincidence – Samuel Sunderland could be a common name.

Pity the patent isn’t online.

Dave

The American patents are all attributed to Sam Sunderland of Keighley, Yorks, England. Sunderland is quite a common name in the Keighley area and is apparently not associated with the town in Co Durham but comes from the nature of the land in the K. area. I’m not a native of those parts so ………..

Here’s a chap who has made a gear planer from scratch. A hero in my book

https://www.modelengineeringwebsite.com/Spur_gears.html