Nice job, good to see some feedback on a post that helped a successful outcome, ready for another 50 years use.

On 1 September 2024 at 19:10 DC31k Said:

Can we assume that the original machine was designed by a competent, experienced machine tool designer, and the components and materials designed (engineered) to give adequate service in an industrial environment?

 

Well, we all know what they say about assume.

The plastic part was most likely designed by a production engineer (I assume!) because it was cheaper to produce than a metal part, not because it was the best possible choice of materials or the only choice.

In the home workshop I’d be doing it in aluminium too. Very nice job done there.

Wade,

Did you make a drawing of it whilst you were about it?  If so I would be interested in a copy.  My mill was no spring chicken when I got it, still turns out good work and it’s done me very well on most of the bits for my half size traction engine – had to extend the table with a heavy plate when I machined to con rod!  Being able to swing and extend the head was a godsend!  Having the horizontal spindle also served well in cutting the gears!  It does have a rattle in the quill though depending on what you are doing and I am expecting it will stop turning one day!

Paul.

On 1 September 2024 at 19:10 DC31k Said:

designed (engineered) to give adequate service in an industrial environment?

You forgot “at a reasonable cost”. Injection molded plastics is very cost effective.

What has changed … that has made the original choice unsuitable?

That’s binary thinking. A more suitable option does not make the alternatives unsuitable, only less suitable.

On 2 September 2024 at 08:28 Wade Beatty Said:

Paul,

I will make a drawing up this week and post it for you. No problem.

 

Wade

That would be very kind, many thanks.

Paul.

On 2 September 2024 at 09:42 Circlip Said:

Correct answer JD2. NOT a cheapskate solution. What is the next weakest link in a jam up? How many 13A fuses are fitted to a 2A circuit? DoHHHHH

 

Regards  Ian.

EMCO V10 owner, (The one with the TUFNOL main drive gears)

I worked on a few Ford V6 engines (2.5L and 3.0L) many years ago and the camshaft gears were made of TUFNOL.

On 2 September 2024 at 11:47 Vic Said:

I worked on a few Ford V6 engines (2.5L and 3.0L) many years ago and the camshaft gears were made of TUFNOL.

I had a number of Scimitars over a period of some 30 years and the early V6 3l engines had the Tufnol gear, all the later ones had a nylon outer bonded onto a cast iron centre.

Apparently the Tufnol ones used to shred teeth until the gap between missing teeth was too great at which point the whole lot dynamited.
The nylon ones worked perfectly until they didn’t – no warning, just disintegrated. The cam gears drove the camshaft directly and clearances were such that a gear failure ensured that every valve was thumped by the pistons – I had one let go at not much more than tickover and another at around 3500RPM – same result, full strip to remove the debris, full replacement set of valves.

Many many moons ago I owned a couple of cars with the “Essex” V6 engine, with the Tufnel cam drive gear.

One day the engine started behaving very strangely, and, combined with the auto gearbox, it was doing weird things, sudden power, sudden no power, changing engine speed with no throttle pedal movement etc.

In trying to find out why, I eventually took the cam gear cover off and discovered that the oval plate that held the camshaft into the block had become loose and had been allowing the cam to move forwards and backwards. Because the drive gear teeth were helical, this movement changed the camshaft timing and therefore the power and torque curves of the engine.

I think that…….ahem……..perhaps I had not torqued or locktited the camshaft oval plate bolts correctly during my rebuild of the engine, but luckily, the cam gear cover prevented the camshaft moving too far, and it stayed within a range such that the cam followers did not “fall off” the edges of the cam lobes – which would have caused instant destruction – but stayed working and moving the valves.

So I owned the first ever engine with variable cam timing – although the timing was completely random and uncontrolled and useless !!!