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About DGentile

  • Birthday July 16

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    Walchwil, SWITZERLAND

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  1. Steve, I don't know whether anyone has ever attempted that, but at least to my knowledge this would be very difficult to implement in a pneumatic tool air system. The problem would be to use some sort of uni-directional valve on the inlet and outlet of the cyinder, then needing some sort of expansion tank on the outlet to handle the compressed air and prevent it from being over-compressed... you´d then need an overpressure safety valve in line... and that yet you’d need to feed in more air to the inlet... and that means some sort of exhaust at some point. I bet you could get it to be more “conservative” in its air consumption by trying to collect / feed exhausted air back into the system. but I doubt you’d add a lot of improvement whilst adding serious complexity and potential problems and cost to the system., Again, I have not tinkered with this. I briefly pondered building a self contained system, but gave up on it due to the complexity of the actual parts.... pefectly do-able but at the required time and tooling to get it done right, you might as well (or rather) buy an anyang new. So I believe the tool air operated hammers should be designed with a certain simplicity and all I’ve seen (my own included) are essentially based on the principals applied in constant pressure steam hammers..., old tech, newly implemented.
  2. Andre, Good choice on the nylon for the ram guide. On the cylinder: if it feels sticky or hard to move about, you have probably found your main issue already. again, as mentioned - whatever cylinder type you use - it needs to be moving very very easily, as pneumatic systems don't like to overcome friction if you want speed. For most cylinders you can buy rebuild kits that include a new set of gaskets, often the piston sliders and the rod bushings... you can get away with *some* DIY fixing if it's sticky... have you disassembled the cylinder yet and checked the insides? if it's air (I looked at the photos again, it's difficult to say, but it could be... I might have been wrong on my assumption of it being hydraulic) - you should really be able to move it almost freely if none of the ports is blocked. Also yes, the 1/4" line is certainly not idea, but I'd say it's not the main issue. Another thing that comes to mind: HOW do you operate the hammer - I mean what sort of ball-valve or other valve do you have installed to let the air out and get the hammer to move with I assume a foot-treadle or something? here's the thing, those hammers operate on "constant" pressure systems, not unlike old steam hammers, they start to move, once you let air escape and get the system to cycle - but air needs to be able to escape... if your EXIT-Valve (the foot-treadle, ball valve etc) is too small, or doesn't let the air pass QUICKLY the entire system will slow down.. here's my system: (with the support bracket removed) I use a 1/2" Ball valve and 1/2 pipe fittings - and most important the filter / muffler (I use a different one now, that has an oil-catch & drain...they are expensive, but last far far longer as the filter doesn't get clogged with excess oil from the oiled-air)... the muffler - if you have one (and I do recommend one for noise and because of the air pollution the oiled air would potentially cause in an indoor-shop) - needs to be rated for really large volumes of air being passed through. Again, anything that prevents the "trapped" air from exiting quickly will actually stop the hammer from being fast. My design uses a sprocket and chain to operate the ball valve - the entire thing is supported also by a ball-bearing live center (made from an old unused lathe live center tool).... Chain and sprocket allows for a fast, yet very precise control over the ball valve.
  3. I don't post often (actually hardly at all - lack of time mostly)... but I've been running a 110pound air hammer that I had built while back, very successfully... so I thought I might be able to provide some help... First, your cylinder looks like the hydraulic rather than the pneumatic type... this itself can be the main issue .. whilst functionality wise both are similar in what they have to do and how they achieve it, the air (pneumatic) cylinders are optimised for low friction gaskets and the piston moves very very easily (even by hand), where a hydraulic cylinder doesn't have any problems overcoming high-friction inertia by VERY TIGHT gaskets and fits... after all oil can not really be compressed... where air on the other hand is easy to compress...... I know that there are a number of builds out there successfully utilising hydraulic cylinders in pneumatic systems - but I figure there's some modding to be done, or at least a serious amount of piston-gaket lubrification to be added... So one of the factors you could easily and "affordably" change is to use a proper air cylinder... now Speed on an "tool-Air" power hammer is usually down to these factors from what I understand: air-pressure & volume being moved into the cylinder at speed... so a "slow" fill will result in a slow move of the cylinder,.... a slow move will also cause the return valve to be triggered in a slow cycle and then you get a slow move over all... as seen in your video. so with that in mind, the actual cylinder's bore has a rather big impact on the speed of the hammer. bigger bore -> more air needs to be cycled... also try to find areas which can generally reduce the volume of air being moved at speed: small hoses, small diameter reductions, small joints, etc... essentially beef up all the connecting hoses etc... also the inlet needs to be as large as it can be.. you want fast movement of air volume. and again, the cylinder... a pneumatic cylinder with the ports unplugged, can be moved VERY easily by hand... add friction and the entire system will slow down (this is my suspicion in regards to your hammer's issues)... so the standard hydraulic cylinder is most likely the main cuprit here ... pneumatic systems aren't great at overcoming friction inertia... the cylinder's rod needs to be able to be moved VERY easily and freely... otherwise it'll cause a number of issues. again, I myself use a pneumatic cylinder and have only seen a few adaptions of the design using hydraulic cylinders in an air-system.... I can only guess what can be done to get it running smoothly, like changing the gaskets for something with less fritction, adding more oil / lubrification... but again, that's just guesswork. Adding to that, the guides for the ram on your hammer: how tight a fit are they? if you look at most of the TOOL-AIR (external compressor) air hammers out there, the ram-guides are always a rather loose / sloppy fit (check out the videos from the bigblu power hammer and their gib adjustments on youtoube)... same as with the actual piston friction, adding friction by using too tight or not well lubricated guide systems to the ram will increase the drag and slow down the entire system because the pneumatics will have to overcome a lot more resistance to get moving. also from the looks of it, your guides are Steel with the steel ram inside... at least add some bearing bronze or HDPE plastics.. anything that provides better gliding abilities than steel on steel... at the very least add a LOT of grease... but again, steel on steel isn't optimal for an air hammer of that make.... it's quite ok on a mechanical spring hammer like the tyre hammer etc... but not on an air hammer. you want the least amount of friction on the moving components without having a wobbly fit.... My hammer uses a fully adjustable guide system made from self lubricating bronze and has a central lubrification system as well to easily and quickly lube all the guide-ways... If I adjust it too tight, the hammer will loose a lot of impact force and speed.. I find it quite crucial to carefully adjust the guides to have just a little bit of play - clamp them onto the ram, and the hammer just will not work proper. too loose and it won't be ideal either... hope that helps... here's my hammer and the video on youtube shows it doing some work: Build Photos: https://photos.app.goo.gl/2819hrkWQXS5l0n92 Videos
  4. Geoff, it didn't put me out of work - it gave me a third degree burn on covering about half of the length of my inner arm... that was a nasty nuissance and a bitch to keep clean... and I discovered I'm better at doing debridement than I would have expected ... the problem was anvil base had worked itself loose (only held in by bolts, on welded on brackets... they didn't take the constant beating well, two had loosened up mildly, and one had a crack that I had failed to register when I did some maintenance... So working a bigger billet held with tongs, the anvil shifted and it kind of grabbed the steel and spit it back at high velocity towards my arm (wearing a T-Shirt).... the rest you can imagine, a 2x4x5" billet of 1200°C steel getting thrown at your arm at speed... The hammer wasn't strong enough for what I wanted to do anyhow - so rather then spend time to repair and reinforce it, I had decided to junk it and build a 40t Forging Press - that I have been using ever since. The hammer you have built looks excellent though. And frankly if I'd build another power hammer I either go pneumatic or with a design such as the one you have pictured ... I believe on a self-built mechanical powerhammer it is one of the best designs (little-giant style) I've seen. Just one word of caution: get a cover for the front.... there's a reason the cages are around most of such commercially made hammers...
  5. re-linked / reinserted the previously broken photos... (had moved photo hosting... sorry)
  6. Guys, I've finally did manage to update the broken picture links... all should show up again. sorry.
  7. Danke dir Jokke, für die Links... (thanks Jokke for the links...) Die Firma (inzw. sinds zwei): http://berghuetten-gmbh.de/ und http://www.hightech-ceram.de/index-de.html hab' denen mal eine mail gesendet ... mal schauen. Beste Grüsse Daniel
  8. Tristan Thank you for your reply. I hadn't thought about the possibility to make my own crucibles... I'll have to look into that and the availability of the materials locally... I've got a good source for the graphite crucibles though - prices are "moderate" (not cheap)... and have had good results with those so far... But of course, they break - and if I could make my own it would be even better. Charcoal / coke / etc. is completely out of the question. I would need to install a completely different vent-system to the current shop and charcoal in such quantities is far more expensive than anything else I could use. Also I'd like to go with something I can rig a controller to easily - so I can get a more controlled, repeatable process. Personally I think I'll go with a Multi-Burner LPG Setup with forced Air maybe even compressed air (high pressure injection / mixing burner) as they're used in large industrial waste-combustion facilities. The burners & reaching the req. temperatures aren't my concern - I've built plenty different burners over the years that were able to deliver these temps. The "problem" I have at the moment is mostly about effective & lasting insulation of the thing. I'm in contact with a german company who supplies fibre insulation (vakuum formed fibre boards) up to 1800°C (3270°F)... but I have not yet seen the actual technical specs... so I don't know how well they'll hold up at about 1500-1600°C over longer periods of time. Also the other thing I'm not yet happy with is how I support the crucible inside the furnace at those temps. Something that's rigid enough to hold the weight (4-10kg + crucible) at those temps... here most of the ideas I have will not work upon closer examination and experimentation. The most practical solution so far is a composite build like this: Outer Shell from 2-4mm stainless sheet, Octagonal shape Inner insulation, outer-level from Ceramic fibre board to 1500°C about 2" thick Inside stable Insulation from Hight Temp Bricks (1800°C) with an included support for the crucible made from the same brick. Burner from Stainless Steel & Ceramic nozzles four Burners, Side mounted, with a 40° upwards tilt. Pointing at the lower third of the crucible Lid for the furnace made from stainless steel & 1800°C Fibre board. The whole furnace housing & lid can be raised, leaving just the base & crucible & burners "exposed" for easy removal & repairs. But again, most stones at those temps become quite "brittle" .... crack easy and don't handle weight that well... if the mass of the holder is large enough to supprt the crucible it's going to be a huge temperature "draw"... the other idea is electric: ... Advantage: less risk & easy to maintain. & easy to control I can get pre-assembled blocks of insulative material & heating wire (pre-mounted to the block) - ready to assemble for temperatures up to 1650°C... however the cost of those parts is a bit "prohibitive". it's going to be a huge power-sucker though.
  9. Well it's this time of the year again, when winter should have died half a decade ago and lil' birds should be singing... But it's still to cold. Well... that makes it the ideal tool-building time for me... as I'm not too keen on getting out of the shop Shitty weather aside: This is something I've been pondering for a long while.... I'd like to get something like a "production" wootz-making furnace. I've made wootz like three times (one time not that successful, the other too quite ok - but really just minor quantities for experimental purposes.) So I've got a slight bit of an idea on how the process works - but of course I'll need more experience. But I'd like to build a permanent furnace to make wootz. I'll be using graphite crucibles... those are easy to get. But what on the furnace... Would you go with Gas? Oil? Electricity? How about a controller? What type of materials? My idea / wish is a furnace large enough to make about 4-10 kg of Wootz with each run. As the process is quite time consuming - I'd like to make enough of it for at least a couple of blades with one run. Also the other thing is: the furnace should be able to last for a long time. As most know I've successfully built several kilns, forges, etc. over the past 15 or so years. So the question is not about "how do I make a furnace"... but rather specifically on one that works well for the wootz on a long run. Any inout welcome! thanks.
  10. Dan Impressive - beautifully impressive... one of the nicer looking shops I've seen ... must be a pleasure to work in such an environment. congratulations!
  11. JJ, The book is still very much valid when it come to practical stuff... sure it doesn't feature the latest info in Carbide-Cutters (changeable or full carbide), CNC, etc... but for basic machine operation it's a good ref. I've looked at that book, and reg. the PDF - check out pages (PDF) 34-62 (working meth. of a cutter) Page 163 (cutting Speed HSS) ... Stuff to look out for: What too for what purpose Cutting Speeds Mounting stuff and centering/aligning the cutting tool with the work-piece Also as Dan said, climb milling is a no-go on most normal machines... My Aciera can take it if I go really easy about it - and only if my tooling is really nice and sharp. but you risk ruining work-piece and tools quicker than you would believe it. it can yield much nicer surfaces on certain materials and with certain operations though but in 98% of the situation, "Conventional" milling is what you'd want.
  12. JJ, Yes you can cut external curves - but you need a special contraption: rotary table... Quick-Change collets... at least the one on my mill (an Aciera F3) doesn't add a lot of chatter / vibrations... it's actually true enough to keep stuff within a very good precision. But my ER32 collet holder was rather expensive... I had a cheap one before that - and it induced a lot of problems on it's own. ... I'd advise to take some machining classes or at least get a few machinists handbooks... these books can give you the basics on type of tools for what kind of job, setting up the work on the mill, adjusting speeds, etc. milling can be fun... the photo below shows my mill with it's table angled, head tilted, rotary table installed and I'm milling "knife-edge" inside slots on a venturi burner tube: And another bit of advice: if you buy tooling, don't opt for cheap - it'll cost you more than a good tool, as you'll run through it too quick and the results often will show it too. You don't need the highest grade stuff available for 90% of the work - but something in the middle....
  13. Give it a bit of TLC... the rusty aspect makes me cringe ;O)
  14. I'll keep this short: I'm with owen, Jim and Howard here on this topic - I find voting for stuff not in the best interest of the board... some sort of a pinned archive - maybe why not.... but hall of fame: there's simply too much "ego-gone-wrong-potential" in the mix of voting and stuff... I have never been to keen on social-networking features of the interenet expect "normal" Forums... Don't see a need for all that +like, rating,etc... stuff
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