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John N

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Everything posted by John N

  1. go for it! Ive not done that much twisted patternweld, but if it makes a creak noise stop and re-heat!
  2. That may well be an option going forward! - Ive had people asking for power packs without the press as well Re the tonnage calc above, in Europe we work on 2240 lbs to a ton, so the Coal is sub 8 metric tons. Ive got some nice photos of the Massey '12' first batch in work, I've put them on instagram (@non_jic) - Ill post them up here soon. Im too tired to remember how to do it now! wife has the covid so cant do the school runs etc, so Im doing Daddying from shit o'clock in the morning - work for a full shift, then daddying to fall asleep time. grrrrrr
  3. I jump as many grits as possible. I regard each successive grit as only removing the 'ridges' from the previous one, not grinding 'virgin' steel, just knocking the ridges off. I dont see the point in doing this progressively. I don't get on with 24g belts, but never tried a quality one, on a suitable machine. 36g ceramics sometimes. I generally go 60 / 120 on the belt grinder. Its only a couple of passes at 120 to move the ridges from the 60 grit. All the work is done with the coarse belt. I then hand sand (or use a wet stone grinding wheel, but that's not relevant to this conversation!) A 120 grit 'hand sand' is a totally different finish to a 120 machine belt finish. The trick to efficiency for me is getting it 'true' and accurate with the coarse belt, everything else is a finishing operation, 120 machine grit is a couple of passes, and if your accurate, hand sanding takes no time at all. (ie, not chasing a wobble out of it for hours hand sanding)
  4. Knives look great (beautiful) - I'm in the camp that the edges are probably too flat for general purpose board work on 2 of them. (chefs are fussy buggers!) I played around with lots of edge profiles, and the ones that seem to work best are similar to all the popular and well regarded Japanese and European blade shapes (production and custom, they are similar). My opinion is they evolved over hundreds of years to that shape, as that's the shape they work best.
  5. I would 'buy and try' - it looks good to my (virtually) untrained eye. It can always be sold again, and you are only out the shipping!
  6. As has been mentioned, a hammer like that needs to be about 300 bpm. You have no real mass in the ram, so need to get some velocity into it to get forging energy. Spring rate is wrong, among lots of other things, but get it wound up to a decent speed, then address the other issues as they will make themselves known.
  7. thanks Alan! - if you push hard enough it will start to move eventually!
  8. I'm working on these two machines at the moment! they are just so pretty I thought they should get their own thread! The 2 cwt is my personal hammer, now rebuilt after the fire. The 1 cwt is off to a customer. In the UK both of these machines are regarded as 'Rolls Royce' Not often you see them side by side in nice condition They are both ready for testing next week. Busy busy!
  9. kind of agree (but disagree ) If they are going to be regularly used, use a bit of 'good stuff' for the dies if you can! You will get deformation, and scale is very abrasive. They will end up looking like a dog chewed them, after a while, if they are soft. Beauty of a press is you can get away with sub optimal dies for a lot longer than you will with a power hammer though!
  10. Good honest review, it confirmed a few thoughts I had about the press capacity (I worked it back to 7.75 metric tons from the available data online) It will be worth keeping hold of the small cylinder, as the bigger 8" stroke one has stolen 2" or more of your 'daylight' - which might be a PITA if you want to use the press for punching operations etc! In the UK 'stop blocks' are commonly called 'kiss blocks' - they are usually positioned well off to the side of the die block in use, you really only want to 'kiss it' as it will ramp the press slide over if there is any excess clearance in it, which is bad practice! edit, just re-read what Alan said about using 2 stop blocks, one each side of the workpiece. This would be best practice, but in reality you would end up only putting one side on when 'in the heat' of forging
  11. put some clothes on the blade I posted up last week! Handle is micarta, and Walnut. Im not 100% convinced, but its growing on me a bit.
  12. new machine day is a happy day! Congrats Your cart might need beefing up a bit, the hoses will push and pull a bit when they are loaded up!
  13. I would strongly recommend leaning back and squinting when you load that up! please don't put 20 ton on it, even if you re-weld it. Welding over a bad weld is still, errrm, you know. Not easy to visualise the forces involved, but if a 20 ton anvil block was hanging from a crane, with your press frame as the link, would you stand under it?! - I don't mean to be 'that guy' but better to excercise a bit of caution!
  14. A 'log splitter' press is a very good option, just try and brace the frame, and remove some slop from the moving parts, the frames are really not designed for the 'dead stop' every 1 second you get forging! The power pack on this press is basically 'log splitter' with non standard pump / motor configuration!
  15. A lad I have got to know quite well, Josh, is making some very nice grinders, and accessories. Small outfit, but Josh really cares about making stuff 'right' at a good price point! https://manchestergrinders.co.uk/
  16. not quite yet. there is some heavy spread sheet action going on at work! I have substantially improved and simplified the design, and need to finalise that, and grow a bit of confidence to 'pull the trigger' to make them in batches. Its a bit outside my current comfort zone, as we generally work on 'one off' very big forging machines
  17. Its all quite interesting when you get into it a bit! I am quite liking the simplicity of hydraulic formula! This press is 90mm bore cylinder, which from memory gives 12.3 metric tons (not american short tons!) @ 2500psi. (thats about 8.5 amps, on a 240 volt single phase supply) 1.5 kw motor. Cant remember the ram speed, but that 'is what it is' - the press was designed with power & tonnage in mind, the speed is the 3rd part of the formula, so is what it is! The frame is grossly over engineered, but its functions are more than 'stretch resistance' - We modelled the frame in solid works (FEA analysis), and there was not a hint of stretch, or any hot spots, until 115 metric tons loading! - The thickness of the frame is an easy way to give guide surfaces for the ram (slide). The frame is one piece, it is an 'H' frame, but more accurately described as a ring frame, which has the optimum elastic circuit. I went this route, as I have an unbelievably good profile supplier who grinds to thousandths for incredibly reasonable cost. Material costs way more than fabricating a frame for sure, but its less labour, and technically vastly superior! (and looks cool ) Column stretch is an over simplification of press frame design, you need to consider the entire elastic circuit. If you ran a model on a fabricated frame the stress / strain on the weld interfaces would be crazy! edit for clarification! - the frame of the press is an elongated 'O' profiled from a single piece of 55mm (2 1/4" ish) thick plate (no welding), which is then lumsden ground to 53mm thick. The 'ring' is then welded to a baseplate, with 4 ribs (more for aesthetic reasons than strength!)
  18. gave her a lick of paint to smarten things up a bit. Im not 100% convinced with the colour , but it will look very different when the front and back plates are fitted to cover all the working bits!
  19. Got the knifemaking wind in my sails for the first time in about a year! ground this 240 gyuto I had previously forged, and did a surprisingly neat job! It will probably all be down hill from here, but nice to be making again!
  20. The maximum (whilst fully supported by the frame and ram) is 2" x 6". I codged the dies together from scrap for the prototype to test it, so they are 'sub optimal in many ways'! They are 45 x 140 mm You can have a much wider die on this press than some other designs, as they are held by the front and back clamps (rather than screws going up into the ram, and down into the bed). Ive designed it so you can make dies easily by welding bits onto a plain flat plate, and the clamps locate onto that. The wider dies area should be useful, as you can work off centre as its very solidly constructed, and well guided (minimal 'ramping')
  21. Link will take you to the video! - cant embed thumbnail. I really don't like technology sometimes!
  22. Started this project 6 months ago, its been very stop start due to other commitments, but finally got her under power! A full 12 metric tons, placed inside a 'ring frame' - this is the simplest and strongest design I could think of. I wince when I see presses flexing and ramping under load, so wanted my design to be tight and right! We ran a FEA analysis on the frame, and it does not flex at all until its got over 100 ton loading Press has a 2 horse motor, running at 8.5 amps from a single phase 240v supply (which is the max FLC of the motor) - seems to work nicely. Hopefully we will build these for sale if I can get the cost out of them a bit, if not, it has still been great fun to see it from fag packet sketch to working machine! https://imgur.com/gallery/0ePhypK
  23. When I last did my forges I bought 1600c rated refractory cement from ebay, and cast the floor, and walls with that. It was 1/2 the price a few years ago though! - https://www.ebay.co.uk/itm/264332519138?hash=item3d8b7226e2:g:KhkAAOSwqF5bl-Da It mixes up like lumpy concrete, but is bomb proof once you have gone to the effort! edit to add, I use a couple of inches of insulating wool, with the refractory cast inside that. The refractory cement takes much longer to heat up than wool, but holds the heat when you put the workpiece in, and is flux resistant!
  24. This is the newest power hammer in my stable! - had to downsize things a bit since the workshop whoopsie last year Tod is very good at videos, I just stand and grunt on command - hope you enjoy!
  25. @jamiemackie Footnote to this little heat treat oven design, I did suspect the stainless hangers might have a metallurgical effect on the blade steel in contact with it, on discussion with Jamie at the weekend, he also had a suspicion that an area on a 1095 blade, that was heat treated with clay, polished for hamon had lower carbon where it rested on the hanger. (on a larger version of this deign oven he built) I *think* we concluded (but beverage had been consumed!) - that a bit of ceramic tube slid over the hanger would be an easy solution.
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