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  1. Cogsy

    Parting tool chatter

    Which bit are you claiming was a typo? The 40 thousand feet was supposed to be 4 thousand maybe, or the 40 seconds was supposed to be 400?? - so why did you ark-up when I mentioned the 7 thousand foot per minute climb rate of the F8? It was at best an exaggeration and at worst an outright lie...
  2. Cogsy

    Parting tool chatter

    A meteor was experimentally fitted with non-standard turbojets in 1948 and went on to set a world climb record in mid-1951 of just over 39,000 feet in just over 3 minutes. Well documented and claimed as an official record by the Brits'. I doubt they'd have been crowing so hard if they'd achieved...
  3. Cogsy

    Parting tool chatter

    There's plenty of documentation that is far more accurate than anecdotal recollections of a single person. Case in point - the F8 Meteor had a maximum climb rate ~ 7000fpm and took 5 minutes to climb to 30,000 feet. Documentation from multiple sources is indeed 'first class evidence' and exists...
  4. Cogsy

    Squaring off the bottom of a blind hole

    Well if you want to get really technical (and speak in the language of true geometry) a hole cannot have a 'bottom'. A drinking straw has only one hole and a drinking cup has none. If we drill or bore into a piece of material we don't make a hole unless we go all the way through. Language is...
  5. Cogsy

    Free plans for a larger, simpler, beam engine

    Tiny, nowhere near the micron size but in the Angstrom range. With a molecular weight around 500g/mol then each molecule weighs around 0.0000000000000000000008 grams - that should give you an idea of the size
  6. Cogsy

    Free plans for a larger, simpler, beam engine

    Toothpaste abrasives take many forms, surprisingly even hard compounds like aluminium oxides. Don't brush your teeth too vigorously or for too long or you remove too much enamel.
  7. Cogsy

    270 Offy

    H-section rods abound and have for a long time but there are still significant deviations in some specialised applications (especially high-level racing). Have a look at the profiles used for top-fueler dragsters for instance. Strength and clearance considerations could easily be the reason...
  8. Cogsy

    270 Offy

    I think you missed the point - look again at post #424 which has a picture of the actual rod from a full-size engine. The rod design is obviously staying as close to true scale as possible. As the full-scale engine was a well refined racing engine, I would say the rod design was optimised for...
  9. Cogsy

    LTD Stirling

    Although it's unlikely to make much of a difference on a tiny bearing like that, most bearings are only dimensionally stable to around 110 Celsius (230 ish Fahrenheit) and shouldn't be heated above that or they may permanently deform. SKF 'Explorer' bearings can handle a bit more (about 150 C...
  10. Cogsy

    Marks Holt 75

    I have started a new thread for Johns' Holt and cleaned this one up a bit. Please continue your story Mark - I've been following along and really looking forward to the completion.
  11. Cogsy

    Putting some grip (stippling) on an aluminium drive pulley.

    All snakes in Australia are protected species and it's illegal to kill them for any reason. I have a few living in my house - they make great pets, not smelly at all and don't eat much. Reasonably friendly beasts too. I haven't been bitten in weeks.
  12. Cogsy

    DEMON 2X

    It seems a lot of people use a similar method to you when 'seating' rings but industry suggests it is the opposite of what you want to do to actually get a well sealing ring. The combustion pressures are required to get the rings to 'bed-in' and wear into a good seal. Here's a couple of links if...
  13. Cogsy

    Putting some grip (stippling) on an aluminium drive pulley.

    If I'm only doing something like working on a car or fixing the mower, and it's a hot enough day, then the full uniform is a pair of stubbies, wife beater and thongs. If I'm machining or messing with heavy stuff I switch the thongs for steel caps and if I'm welding then I try and add a long...
  14. Cogsy

    Yet Another Webster Begins

    I was going to suggest the same tool Brian did (we know them as 'side-cutters' down here). Looking at the picture, I would have thought there was enough pin sticking out that the cutters wouldn't even need modifying. Many times I've used side-cutters to grab and manipulate heavy springs, mostly...
  15. Cogsy

    Chinese Vertical Hit and Miss

    Barely any running so far. I've been tied up with real life a lot lately. I have a friend (just the one!) who has the horizontal version and he's had that running for hours at a time without any noticeable loss of compression. He does put a few drops of oil in his fuel to keep it lubricated.
  16. Cogsy

    veterans day

    I think you'll find it was 11:00am precisely (Paris time) on the 11th of November 1918. Had the war finished in 1917 my great-grandfather would not have perished in it...
  17. Cogsy

    ??? Making Setups

    The internet archive supposedly considers itself a library and it holds many physical copies of books, both in copyright and out of copyright, which it digitally 'lends' to users. The way these digital copies are provided to users has long been a point of contention with publishers and copyright...
  18. Cogsy

    Chinese Vertical Hit and Miss

    I'm not sure that flash point has much to do with combustion performance (and my intuition, which is often wrong, suggests WD40 wouldn't burn all that well compared to petrol/gasoline). Anyhow, petrol/gasoline has a flash point around negative 40° Celsius so if flash point==combustability then...
  19. Cogsy

    ??? Making Setups

    I wasn't suggesting the link to the specific publication was breaching copyright, simply that the site itself is jam-packed full of material which is covered by copyright. Simply viewing the posted link will present the user with other "you may also be interested in..." materials which...
  20. Cogsy

    Acceptable castings from Kit suppliers.

    Charles has much more experience with this casting so I'd take his advice and all I can give is my impression - The surface finish on the first, except for the defect, looks good, but the blue one looks like something I would cast in my back yard (and then promptly remelt and try again).