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  1. K

    Plasma cutter setup

    Hi All I have a large 240v plasma cutter, which, when new, cut 4mm steel like a hacksaw cut, with very little slag under the cut. I can no longer get that quality cut and the tips need replacing very often. Like about one metre of cut and replace the tip. The copper part seems to gouge out on...
  2. K

    Face Cutter Woes

    I bought a cheap 2", carbide tipped face cutter on Ebay from China. Most of my tools are Chinese and are fine, but this thing just does not cut. A light cut just squeals across the top without cutting, leaving a heavily scratched surface and quickly making the work piece too hot to touch. It...
  3. K

    More slag and cast iron

    I've been doing some more cast iron castings. Skim the slag off the top, ok, but after pouring, there is a huge amount of slag stuck to the bottom of the crucible. A few questions. Is this actually slag? Can I add something like borax to act as a flux. I thought all the slag would float to the...
  4. K

    Removing sodium silicate sand

    I've just done some cast iron locomotive wheels, first time using sodium silcate. It has set like concrete and I'm having great difficulty removing the sand. Is there a solvent of some kind. Also perhaps next time I should dilute the sodium silicate with 50% water?
  5. K

    Casting shrinkage voids

    I do my own castings for my 5" gauge locomotive and most things work ok. But I'm having a lot of trouble with the cylinders. Quite a large lump of bronze. 4" long with a 1 3/4" bore. I used a 1 1/4" core for the bore. The first one turned out great, but the second one had a large depression...
  6. K

    Slag and cast iron

    I do a few cast iron castings for the model steam trains that I make and I find that the slag that floats on the top is rather difficult to remove. sometimes I pour the molten metal and the slag blocks the runners. Is there a flux or something that makes the slag removal easier.
  7. K

    Thermite casting

    After much trouble I've finally managed to melt cast iron with an oil burner. It takes a long time to melt and is very noisy (upsets the neighbours). I've been watching thermite welding of railway lines on Youtube an thought this could be adapted to casting. Any thoughts.
  8. K

    Drill Chatter

    I bought a new milling machine the other day. For Aussie readers it's a Hare and Forbes HM48. A machine at the upper end, size wise, of the home workshop uasage. Trouble is, it wont drill holes without very bad chatter. I have a smaller milling machine and a pedestal floor drill. Both cut...
  9. K

    Flame temperature of Propane vs Oil

    I have a small propane furnace that I use for casting aluminium and bronze. It works fine but I need to do cast iron. Research suggests a waste oil burner, but why? The flame temp of propane is 1960C. 600 degrees higher than the melting point of cast iron. The flame temp of oil is 2100C. Only...
  10. K

    Sharpening carbide tips

    I usually use 1/4" tool steel in a holder for turning, or preformed carbide inserts. Neither of which are ideal for me. I've seen videos of people maching with the carbide tip brazed on to a steel shank. This looks good for me as overhang is minimal and I can form my own cutting shape. However...
  11. K

    Loctite and brass

    I have a 32mm dia brass disc, 1mm thick and need to drill accurate holes at 24PCD. The plan was to glue it to the end of an aluminium bar and drill it in the rotary table. I used 7471 primer and 680 loctiite and allowed to set for 2 days. The first touch of the drill and it broke away. Tried...
  12. K

    V8 Cylinde head

    Hi I'm new to model engines. My history is 5" gauge live steam locos, but my next project will be a 1/4 scale V8. So much new knowledge to gather. Today's question. Are the heads water cooled. I can see the cooling between the cylinder liners, but not in the head. Link to pics would be nice...
  13. K

    Casting using bronze swarf

    I have access to a lot of bronze maching swarf at a cheap price. However when I fill a pot with solid and swarf, the molten bronze can be poured off, but the swarf is still solid in the bottom of the crucible. The same alloy for the two. I've tried a couple of times, same result. Would be nice...
  14. K

    Expanding fire tubes

    I'm building a Briggs type boiler for a 5" gauge loco in steel with copper fire tubes. I'm new to this and a liitle unsure. The boiler code says the only connection between the the tubes and the end plates is an expanded fit. No soldering. I assume this works, but I'm a bit worried about it...
  15. K

    Shrinkage holes

    As a background, I'm bulding a 5" live steam loco and doing all my own castings. Small ones are ok, but I'm trying to cast the body for the boiler hand pump in brass. It's about 28mm dia, 70mm long with a few bosses and mounting lugs here and there. (I would supply pics but cant find USB cable)...
  16. K

    Forced ai propane burner

    I have a small furnace with a self blowing propane burner. It keeps blowing back and burning inside the tube. Works "ok" for aluminium, but seems when the temp gets up to bronze melting it's a constant battle to keep it working. Anyway, I read a few posts on forced air burners and they seem a...
  17. K

    Northumbrain boiler

    I've decided to build a Northumbrian locomotive from the plans in Model Engineer. I've managed to accumilate most of the old issues but can find no details of the boiler. Does anyone know which issue this is in.
  18. K

    Green sand binder

    I'm having trouble with my moulds staying together. I've made my sand according to guides on the web. Fine sand with about 10% bentonite. But the moulds are very delicate and fall apart easily. I can cast aluminium and brass in them but quality is not good. I bought my bentonite on Ebay as a...
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