Quote " For reasons that still escape me, the text was heavily edited in the introductory sections, and the bits that were edited out made their way into a letter from me in the Scribe a Line page of issue 175."

Tony,

Whippets are a protected species in certain parts of the country.

Graham;

I debated for years, then Neil Hemingway was in il-health, and I thought I had missed an opportunity.

Finally, about a year ago I purchased a kit, had it sent overseas (including metric frame 220v motor) and think it's great.

Is it worth it? Is the brass for my Ivatt 2-6-0 cab worth it?

I ponder the costs so much that my wife just says "life is too short, just buy it"

Current project is doing the Thomas Rolls from Hemingway; nice to have all the bits in one box, as (for me) purchasing materials is long-winded and expensive proposition.

I do have some bits on the Worden on my web site: http://cnc-for-model-engineers.blogspot.com

Just my boxing-day opinion;

Another Johns.

Whippet in, whippet out, and wipe it.

Dennis

Clive,

If I understand correctly what you describe … this can only give support along two diametrically opposed lines.

If there were two pressure pads (say 30° to 60° apart), then there would be three-line support, and therefore much better stability.

Note: This may be bonkers, if I have misinterpreted your description!

MichaelG.

John, with respect, having been self employed as both a wholesale supplier and a retailer for more years than I care to remember I don't think I am missing the point.

I just think that this – for me – is not a value for money package. I would certainly encourage somebody to "go for it" as competition is a terrific thing for the consumer but it is not something I could do right now as I am quite busy thankfully. It is certainly something that is an opportunity though.

The model engineering community is often thought of as a bit of a "target audience" but look at the size of the attendance to the shows, these people could easily be customers. And God knows I think we could all use a drill sharpener that a) works and b) is affordable.

graham.

Clive,

Not built a Worden or used one or even studied the drawings but i do have a good grasp of modern electric motors and the way they are built up today isn't conductive to a precision grinding technique.

For a start modern motors have very loose bearing fits by engineering standards. When I strip a motor down for mods it's very common to just be able to pull the rotor with bearings on out of the end shields.

Also to aid manufacture and tolerances there is rarely any method of controlling end float, the usual way is a wavy washer at the non business end.

This means any axial load on the shaft will push the rotor backwards.

If I was using one of these modern motors for this application I would secure the front bearing into it's housing with a keep plate such as older motors used to fit.

Failing this I would secure the rear bearing into it's housing with a bad of loctite and relocate the wavy washer to the front housing, basically pushing the rotor back as far as possible from the start.

For a start modern motors have very loose bearing fits by engineering standards. When I strip a motor down for mods it's very common to just be able to pull the rotor with bearings on out of the end shields.

Also to aid manufacture and tolerances there is rarely any method of controlling end float, the usual way is a wavy washer at the non business end.

The whole idea of the wave washer is to put a controlled axial preload on the bearings. As the force exerted by the washer is not very large, the bearing next to it (normally the non-drive end) has to be a sliding fit in it's housing.

The reason for the axial preload is to ensure that the bearing balls rotate & don't skid when the motor is run unloaded. This has been standard electric motor design for many decades.

I can't recall the motor shaft on my early Wordon moving under load, but I will check next time I use it. I think that mine has an East German motor fitted. It came "finished" from a Myford open day sale – IIRC I paid £75 for it. Whoever had built it obviously wanted to use it quickly – no paint & rather rough & ready worlkmanship all round. A query on a forum (can't recall which now) brought forth a set of the original drawings, which show that the original builder modified the machine from the published design.

The original design has the bearing block & guide rail next to the grinding wheel, where it picks up grit and gets stiff very quickly. I have only used iy to finish turning tools, as I have no confidence that i could control the table feed accurately enough to try thr ends of end mills. On the "jobs to do" list is to replace the plain cast iron bearing block with a linear ball bushing and design a stop arrangement (the original builder's modification to the angle setting arrangement removed the "as designed" stops).

Nigel B,

Not if you want spare ribs!

Good read

Thank you

" The end result is that I can gently touch the diamond wheel with a fingertip when running and feel no vibration at all."

Just the smell of burning flesh

Martin P

On my Worden, I reamed the wheel arbor when drilled/machined, and as such it is a very tight fit on the main motor spindle.

I have not had any issues with the wheel coming loose.

I have not had any issues with end float, etc. – maybe because cuts are light.

I can see issues if the arbor is slightly too large, but that's not how I machined mine.

I really like it – certainly I do wish that I did NOT have to use it, but somehow tools in my workshop do not magically sharpen themselves, unless an expensive UPS or FexEX package arrives at the takes-two-hours-to-drive-round-trip courier depot. The Worden ends up being both cheaper, *and* faster!

Is it a perfect design? Nope, but then, nothing in my workshop is, including me.

Off to finish my ER25 holder for it –

Another JohnS.

I may have mentioned this before but a nice finish on the Worden top plate can be done with an oscillating sander.

Regards the wheel becoming loose in use, I tighten it up correctly and later find the screws have loosened and then I can move the wheel on the shaft. Re-tighten and its fine,

I am going to re-do the fixings and use another 2 screws at 45 deg. to the center line. Its the obvious answer.

Clive