Member postings for Jeff Dayman

Or a digital fridge....

it would be fun to make a warranty call on a digital toaster and say "My digital toaster is not working, it never imprints the correct time on the toast. (Pause a few seconds for it to sink in) It's five minutes fast, or ten minutes slow......."

Too much time on my hands I guess....

I'd suggest drill rod / silver steel for the stems, with drilled discs of same for the heads, tig welded in place. One carefully placed tig fusion weld (no filler) in the centre of the head on the combustion side would seal it and provide more than adequate strength in a valve of the noted size. In this case with a welded joint a threaded fit would be counterproductive. Just a slip fit would be good. Ideally the weld penetration would be at least 80% through the head and well into the stem. After welding the disc is turned and the seal face ground at 45 degrees while holding the stem in a collet.

I made a few this way years ago for Saito 4 stroke RC plane engines (no Saito parts available at the time locally) and as far as I know they are all still running, and I talk to the people I did them for regularly, they never mentioned any issues.

no doubt about it - things have got stupid with cars and trucks. They have been 4 wheeled computers for many years now, and are not designed for service at all. I have no idea what I will replace my current vehicles with - nothing I see on the market meets our needs and the prices are outrageous. An equivalent new truck to the one I bought in 2010 for $35000 CDN is now over $80000! Never get done paying for it!

I have been seriously considering just giving up the search and buying a $25000 CDN throwaway Korean made base model car, use it and in 5 years when it is worth nothing at trade in, decide to run it till it quits or scrap it. Much cheaper than an $80000 choice! (but no comfort for tall people, poor driving quality with the electronic "assists", and iffy safety in collisions)

European made vehicles are not an option for us, with prohibitive initial cost and outrageous repair costs here, a friend with a BMW 6 yr old was just quoted $8200 to replace some fuel injectors and ignition coils.

Cars and trucks have become appliances, boring as hell generally. Just my opinion.

last one I bought was made in Mitutoyo's Brazil factory. Bad quality mechanism, slide full of greasy grit too. Poor value for money, I was very disappointed as they were a brand I trusted before. Very unlike previous ones I bought over the years (for me and for firms I worked for) made in the far east which were very high quality. I won't be buying any more Brazilian made Mitutoyo instruments.

Beware of yout ubers showing exotic processes that are hard on equipment. Chances are you can do any job several other ways that are simpler and easier on your machines.

Same goes for the yout ubers chasing millionths of an inch measurement or grinding oilstones and surface plates for sub-tenths of a thou accuracy - sure it's a neat mental exercise and skill test but you can have just as much or more fun building steam and other engines and many other things with nothing needing anywhere near sub-thou accuracy.

Life is short, have fun with semi worn out junk! (as much of my equipment is)

You can buy a lot of expensive adhesives from people whose job it is to sell it, and spend lots of time experimenting, only to find out:

1. it kind of just barely adheres to the low surface energy acetal parts, a very weak bond.

2. if the parts flex at all, or any load is applied, weak bond breaks.

3. If the temperature changes, weak bond breaks.

4. You then spend many hours in calls to the manufacturer / salesmen listening to excuses about field conditions being different from test lab conditions, questions about did you get it clean enough, dry enough, rough enough, with the right additives / accelerants etc, did you wait long enough, and looking at beautiful test charts. Bonding Failures will always be your fault, not the adhesive makers.

5. The salesmen will start to suggest special treatments to change the surface energy of the parts, like laser etching or corona discharge. If you go down this route, expect huge equipment costs and no tangible improvement, and no warranties or return policy whatsoever on the equipment.

6. After some time interval doing the above you will not be able to reach the sales people any more, or you will be told they have moved on to a company selling toilet cleaner, artificial fingernails, cars, etc (or prophylactics, in one case)

The above is based on multiple experiences trying to glue polymers in industry, much of the time spent trying to glue acetals and polyethylenes .

Acetal is NOT like other plastics that glue well, or metals that bond well with anaerobic adhesives.

"PPS Luck your house has all the walls at Exactly 90deg"

As if that has ever happened! (I'd settle for 'somewhat planar' in our house)

Glad it's running Martyn!

Good point Neil, inlet and outlet ports for slide valve steam engines are both useful items but are hardly interchangeable......to paraphrase Col Potter on the old MASH show, talking about something else.

Beautiful detail work Steve! well done.

In my experience there is no adhesive that will work on Delrin / acetal. One of its' most useful properties is its' anti friction self lubricating quality, particularly when run against metals.

It will need to be pinned or clamped mechanically to a mandrel. Washers made from sandpaper can help.

Just a second thought - did you check for cracks between steam ports and exh port? or for erroneous drillings too deep from steam port into exhaust port? as unlikely as they seem these things have happened from time to time. (especially if you have taken over a partly finished project - no idea whether your engine originated that way)

Don't forget the good dollop of heavy steam oil - this often helps first seatings of slide valves. Good luck.

Why you are still allowed to make belligerent posts about ignorance is beyond my comprehension.

Perhaps you could share some factual references to the works / thoughts of Mr. Goss, Young, Ell, and Koopmans instead?

sandblaster or wheelabrator should shift the tea can muck (and maybe the tea can)

I will always remember his "secret life" episode on the car engine, poking the oil filter of a running 4 cyl engine with a chisel. I remember yelling "noooooo!" in front of the tv before he got a 10W30 bath! He is truly a mechanical genius, and great fun.

Edited By Jeff Dayman on 23/03/2021 19:42:28

As Jason suggested it could be the valve not seating. I suggest you make sure it is free to move on the nut, sitting on the port face, but not sloppy, and apply a good dollop of steam oil, then re-test.

If you truly need an exact 45 degree angle as you say, I suggest a sine bar setup to make an accurate jig to hold the work in a surface grinder. You will get an exact 45 degree angle very accurately positioned from an edge with this method.

Faffling around with plastic toy tools as you show in the pics is much less likely to produce accurate results repeatably.

Ivan's a hoot, well worth a look if you are into cars at all.

Oh and the rope will plug any water leak, in a pinch!

Looking great Bob!

Given the low cost of "4 way" so called "Universal" drill chuck keys such as the one at the link below, I would suggest you save your shop time for your model engineering projects rather than making your own key. There are many sizes, as the data sheet shows. I am sure you COULD make your own, with a lot of careful measuring and multiple trial and error tests, but not sure why your would want to, for a mass produced item.

https://www.mcmaster.com/3175A36/