Gerhard Gerber Posted March 15 Share Posted March 15 https://youtu.be/VEVmXViW34c Algorithm sent this video my way over the weekend. The machinist that trimmed my contact wheel needs work, and the mounts on my new grinder makes this easy to fit, I really like the look of this Link to comment Share on other sites More sharing options...
Pieter-Paul Derks Posted March 15 Share Posted March 15 I do like that design and I am a dedicated freehand grinder. Looks nice and simple and adjustable for different knives. Notice that he does use a mist coolant system, without I think thin blades would get hot fast. 1 http://mefecit.nl/ Link to comment Share on other sites More sharing options...
Gerhard Gerber Posted March 16 Author Share Posted March 16 I noticed that, but didn't consider it, you have a point. Perhaps rough grind with the jig and freehand for the post-HT grind. Maybe a finder on the blade in front of the bearing to keep you honest with the heat? Link to comment Share on other sites More sharing options...
Jaro Petrina Posted March 16 Share Posted March 16 18 hours ago, Pieter-Paul Derks said: I do like that design and I am a dedicated freehand grinder. Looks nice and simple and adjustable for different knives. Notice that he does use a mist coolant system, without I think thin blades would get hot fast. I have ground freehand for years and now I have ground few blades on free moving jig and you can literally go one whole side without cooling, because it does not burn your hand. Link to comment Share on other sites More sharing options...
Alan Longmire Posted March 16 Share Posted March 16 4 hours ago, Jaro Petrina said: I have ground freehand for years and now I have ground few blades on free moving jig and you can literally go one whole side without cooling, because it does not burn your hand. That's what I have found with my folder blades. Then again they are tiny... Link to comment Share on other sites More sharing options...
Jerrod Miller Posted March 16 Share Posted March 16 4 hours ago, Jaro Petrina said: I have ground freehand for years and now I have ground few blades on free moving jig and you can literally go one whole side without cooling, because it does not burn your hand. I think the fear is that you would over heat and ruin the temper. Keeping your bare hand on the blade is a thermometer to prevent problems. Too hot for you means time to cool it to ensure you stay below temper temps. Link to comment Share on other sites More sharing options...
Simon W Posted March 16 Share Posted March 16 Interesting to see a few different grinding & jig layouts. I've been struggling to be consistent & even freehand, so I may have to try some of those out. To be fair, I've not had a lot of practice on a belt grinder. Link to comment Share on other sites More sharing options...
Gerhard Gerber Posted March 17 Author Share Posted March 17 My first mentor preached freehand only, and I believe it's a necessary skill. I've never felt the urge to use the normal type of grinding jig, and my work rests aren't suited I believe, but I feel my skills have regressed from where they were. Maybe a physical issue, or simply lack of practice, but I feel I need help because I'm struggling with symmetry between left and right hand. What gets me is the problem seems to be when my right hand is supporting the blade, left hand is a tool in that situation, right hand stupid and useless. Link to comment Share on other sites More sharing options...
Will Robertson Posted March 17 Share Posted March 17 On 3/15/2023 at 8:03 AM, Gerhard Gerber said: https://youtu.be/VEVmXViW34c Algorithm sent this video my way over the weekend. The machinist that trimmed my contact wheel needs work, and the mounts on my new grinder makes this easy to fit, I really like the look of this Thank you very much for posting. I grind freehand but I've been thinking about something like this for the future. The risk of heating and damaging the temper of the steel is an important subject in sharpening professional chainsaw chains. I usually sharpen by hand but when saw chains are sharpened by machine it's important to take light cuts and make sure that the temperatures reached aren't hot enough to damage the temper of the steel and wreck the chain. I reckon that the mist cooling may be a good idea - I see that used in lathes and mills as an alternative to flood cooling in some situations. Link to comment Share on other sites More sharing options...
Bob Ouellette Posted Thursday at 09:43 AM Share Posted Thursday at 09:43 AM On 3/17/2023 at 9:11 AM, Will Robertson said: I reckon that the mist cooling may be a good idea - I see that used in lathes and mills as an alternative to flood cooling in some situations. I have a mister set up on my grinder. I'm addition to keeping the heat down, it also keeps the amount of dust in the air down. I also have a catch hooked up to a cyclone dust separator powered by my shop vac. The biggest problem I have is not having a way to direct the runoff water that doesn't make it into the vacuum tubing. Bob O "When I raise my flashing sword, and my hand takes hold on judgment, I will take vengeance upon mine enemies, and I will repay those who haze me. Oh, Lord, raise me to Thy right hand and count me among Thy saints." My Website Link to comment Share on other sites More sharing options...
Gerhard Gerber Posted Thursday at 02:03 PM Author Share Posted Thursday at 02:03 PM I watched a video by a South African maker who does a lot of straight razors, by necessity he uses water but I hesitate to call it a mister, more a dripper in his case. Can't imagine the mess that would cause without a good catch system, something I don't have space, time, money or energy for. Link to comment Share on other sites More sharing options...
Alan Longmire Posted Thursday at 04:42 PM Share Posted Thursday at 04:42 PM Peter Johnsson has a continuous flow water cooled grinder, just a KMG chassis mounted on an old milling machine table. The milling table was designed for flood cooling, and has the drains built in. The used water goes through a settling tank and filter and gets recirculated. That would be my ideal, but I don't know if I could deal with the mess. Plus I like 3m Trizact belts, and they can't be run wet. Link to comment Share on other sites More sharing options...
Jan Ysselstein Posted Thursday at 06:02 PM Share Posted Thursday at 06:02 PM (edited) Alan ...I spray some water on a mounted trizac belt and do a short grind and repeat and so on. The belt holds up pretty well. Edited Thursday at 06:03 PM by Jan Ysselstein Link to comment Share on other sites More sharing options...
Alan Longmire Posted Thursday at 08:29 PM Share Posted Thursday at 08:29 PM Are they the gator-grit textured ones that look kind of like tire tread? Every time I grind a wet blade on one of those it just turns to mush... Link to comment Share on other sites More sharing options...
Will Robertson Posted Friday at 01:42 PM Share Posted Friday at 01:42 PM 14 hours ago, Bob Ouellette said: I have a mister set up on my grinder. I'm addition to keeping the heat down, it also keeps the amount of dust in the air down. I also have a catch hooked up to a cyclone dust separator powered by my shop vac. The biggest problem I have is not having a way to direct the runoff water that doesn't make it into the vacuum tubing. What about taking water, sludge and everything from local extraction into a wet and dry vacuum cleaner? There are cheap wet and dry vacuum cleaners at a farm supplies company over here that sort-of do a primitive cyclone separation followed by optional filter. They use universal motors so their speed and the suction can be controlled by a cheap SCR speed controller (there is pressure to phase out this sort of vacuum cleaner motor and replace them with more expensive, more efficient motors now though so not sure how that picture will evolve). Having traces of abrasive particles getting into the motor would likely wreck the bearings fairly fast but at the moment they're cheap enough that it may be OK to live with that and replace them when needed. Link to comment Share on other sites More sharing options...
Will Robertson Posted Friday at 01:48 PM Share Posted Friday at 01:48 PM 17 hours ago, Alan Longmire said: Are they the gator-grit textured ones that look kind of like tire tread? Every time I grind a wet blade on one of those it just turns to mush... The undisputed masters of mist cooling are maybe dentists - the modern high speed dental drills have an air supply for the turbine and independently adjustable air and water supplies which combine to form a jet which cools the bur and the tooth as the dentist works - without that the heating caused would cause significant pain and necrosis of the living parts of the tooth. Handpieces with this capability are surprisingly inexpensive now. Link to comment Share on other sites More sharing options...
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