dps9999 Posted December 13, 2015 Share Posted December 13, 2015 hey guys so i got a new kmg grinder. i know this question has been asked before but i think maybe it might be a question with a evolving answer as people try new things and new products. i would like to know where every one weigh's in on grinding belts. the first set of belts i got was a mix of a couple different companies that was suggested to me so i just did what was suggested as i wanted the belts asap...however i was told these belts go fast using 1 or 2 of many different grits on one knife. i guess that changes on design and size of a knife. so i did some reading and i am torn am i better getting cheap belts and going though them like crazy or spending more and maybe being able to stretch them for more than one knife...i think the answer might be somewhere in the middle and different on each grit...the 3m "gator belts" seem interesting any one use them? so basicly what does every one use?...any advice relating to this topic for someone starting out? thanks guys Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted December 13, 2015 Share Posted December 13, 2015 Get the best belts that you can afford! I usually forge my knives very close to final shapes and could easily rough grind a half dozen small to medium knives with ONE of my ceramic belts! I do like alox belts for final sharpening... and they do wear out quickly! Quote Link to comment Share on other sites More sharing options...
dps9999 Posted December 13, 2015 Author Share Posted December 13, 2015 bigfoot...on the blades you forge how close do you get them , how much material are you removing....i have only done one by forge and a couple stock removal (in the middle of one now) but i am still new Quote Link to comment Share on other sites More sharing options...
TacticallySharp Posted December 13, 2015 Share Posted December 13, 2015 I mainly forge very close to shape also. I profile with a 40 ceramic and cleanup prior to Heat Treat with a 120 and 220 ceramic. After HT I sat with a ceramic 220 and work through 4 different gators. Getting finer with each. I sometimes use a Scott Brite belt for a satin finish. I buy my buys currently from Phoenix Abrasives. Greg has a good selection of quality belt at a reasonable price. When I started I used cheap belts. I found that quality belts not only lasted longer but, cut cleaner and created less heat. Buy the best you can afford is a very true statement. You will save in the long run. Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted December 13, 2015 Share Posted December 13, 2015 Typically I remove about 1/32" of metal on each side to create the rough bevels. Around an 1/8" or so to profile the blades. I start with 30 grit ceramic if I have a lot of work to do... follow with 60 then 80 grit ceramic... then 120 and 220 alox. I can get to a hair shaving sharp with a diamond hone and steel from there. My type blades I hardly ever try to polish them. With my 2 hp grinder and a 30 grit ceramic belt you could grind 1/2" steel to an axe bevel in minutes! Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted December 13, 2015 Share Posted December 13, 2015 one silly thing to avoid is some feel a need to use every grit available, there is no need to use 40 then 60 then 80.. I use 40 then 120.... its saves work and money... Quote Link to comment Share on other sites More sharing options...
dps9999 Posted December 13, 2015 Author Share Posted December 13, 2015 Lots of good info Thanks guys.....I think what i may do is get a few cheap ones in a low grit for roughing out the shape and maybe cheap ones a lil higher grit for some work on handle's and then spend the extra money and get some good ones for final shaping of the blade and handle and the bevels since i think that is the most important i dont want cheap belts there. where does everyone get there belts...the first batch i got for the grinder was from TRU GRIT i have been looking around tho checking out prices just curious as where all of you guys go. TacticallySharp....you said you were getting them from Phoenix Abrasives i am assuming your grinder is not 2x72 right? i didnt see any 2x72 belts in there catalog...maybe i missed it. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted December 15, 2015 Share Posted December 15, 2015 all of this has been covered, including the supplier list. in the knife making section. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted December 15, 2015 Share Posted December 15, 2015 On 13 December 2015 at 11:09:21, Steve Sells said: one silly thing to avoid is some feel a need to use every grit available, there is no need to use 40 then 60 then 80.. I use 40 then 120.... its saves work and money... The standard approach in the finishing industry is to double the grit number with each successive belt. I understand that this is the most efficient balance between optimum metal removal, maximum scratch removal and minimal heat input. So although I am not makings blades, I work somewhere between your two examples if I am finishing a series of elements. I would use 40, 80, 160. If I am just doing one smallish piece I do the same jump as you with just a couple of grit sizes and save the belt changing time. Alan p.s. Edited to put in optimum metal removal. You want to take the metal you don't need away fast , but don't want to be taking metal away just in order to get out deep scratches from the previous belt. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted December 15, 2015 Share Posted December 15, 2015 define fast 40 grit blaze belt on my Bader B3 I can take 1/4 inch off in one pass.... but I prefer to hammer to general shape so there isnt much left to remove, and only the time it takes to change is to grab the belt and depress the spring to change, its not long... took more time to type it that does to change them with a properly made machine. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted December 16, 2015 Share Posted December 16, 2015 8 hours ago, Steve Sells said: define fast 40 grit blaze belt on my Bader B3 I can take 1/4 inch off in one pass.... but I prefer to hammer to general shape so there isnt much left to remove, and only the time it takes to change is to grab the belt and depress the spring to change, its not long... took more time to type it that does to change them with a properly made machine. Well Steve, I am sure your grinder is much more powerful and better built than mine. I am sorry if you felt I was belittling it. The point of my post was to give the reasoning behind a progression of belt grits. And while I agreed that your example of 40, 60 , 80 was counter productive, I wished to show why 40, 80, 160 was not "silly". Obviously I failed to explain it adequately. The point of mentioning optimum metal removal was to underline that the mindset applies throughout the process, the grinding is only a part. Precisely the same as you mentioned above...you prefer to hammer until there isn't much left to remove...The closer the original billet is to the final forged element, the less forging is required, the closer the forged element is to the ground and fettled form, the less grinding is required, the closer the ground surface is to the final patina the less polishing is required...and the progression of belt grits means that you are not having to remove more metal than necessary with too fine a belt. It is the same mindset at every stage of production which maximises efficiency. You take every process as far as you can to reduce the slower effect of those subsequent. I also think this principle of immediacy has a positive effect on the aesthetics of a piece...that it looks fresh and not overworked... But as I said I am not grinding blades. Mine is just a standard industrial 150mm (6") x 2000mm (79") belt grinder with a 4 or 5kW motor. Every time I change the belt I blow off the grit and empty the spark catcher bin and the dust bag and it does take longer than I took to type this...on second thoughts seeing as the first second third and fourth time I tried to respond to this, the forum software disappeared my post it probably does take less time to change the belt than typing it out a few times! The last major grinding job I did with it was putting a full hemisphere onto the end of 36 lengths of 1500mm (5') x 50mm (2") square 316L stainless steel. With a 36 grit zirconium belt I could just get a hemisphere completed in one go before my arms fell off. Your 1/4" in one pass is very impressive, what width of cut and thickness of metal are you talking about there? Alan Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted December 16, 2015 Share Posted December 16, 2015 Alan we are on the same page, and talking about the same things, in about the same way. I was stating to not worry about belt changing time to stop you from changing the belts as needed. I don't expect everyone to pay over $2k for a 1.5 HP knife grinder unless they are doing enough work to pay for itself. I worked over 15 years making knives before I bought it, before that I went to my teachers place and used his under powered Wilton Square Wheel 2x72 and a 1x30 from harbour freight before I got to the point where I made enough money making blades where I could afford and justify the Bader machine. I want to make clear that anything we can do to speed up the process of changing belts or contact wheels leaves more time to focus on the blade, without the distractions of adjusting the machinery getting in the way of the flow of ideas. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted December 17, 2015 Share Posted December 17, 2015 Absolutely agree. I never cease to be amazed at my tardiness in upgrading to a greater capacity tool...why didn't I do that years ago? Although the surprise and pleasure in the speed wears off with familiarity, it bounces right back if you have to revert to the old tool for any reason! The grass is always greener...I used to be envious that my woodworker father could go from lump of tree, to finished and refined bowl on his lathe with just one chisel and a bunch of shavings to burnish the wax in. He used to be envious that if I cut one leg too short I could weld a bit back on... The ultimate in speed and efficiency with no down-tool time must be the potter with a lump of mud on a wheel, spun into a vessel with just her fingers. I used to work next door to a friend's pottery and often wandered in just to watch her throw. Those experiences have coloured my aesthetic approach and so I have always tried to leave stuff straight from the hammer, with all the forming marks recorded. e.g.Unless it detracts from the character of the piece, I mostly leave any weld fillets unground and any rivets showing by way of celebrating the construction. So I understand your position re the belt changing as an impediment to the process...there is obviously nothing else for it...one day you will have to purchase an array of your Bader B3s and have them radiating around your swivel chair so you can go from grit to grit without even changing your hold on the blade! Alan p.s. thank you for adding the previous post into the thread Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted December 17, 2015 Share Posted December 17, 2015 dps; IMO your plans are backward! The most important belts are the ones for coarse removal! Spend your money there! High grade ceramic belts will work much faster and yet cooler! I use inexpensive belts for final finishing. VERY LITTLE metal is removed with these belts! If you want to get a high polish you can spend some money for the specialized belts that do that! In the 120 to 280 grit range inexpensive aluminum oxide belts are pretty effective! For rough grinding you can actually save a LOT of time and money with more expensive high end ceramic belts! Quote Link to comment Share on other sites More sharing options...
dps9999 Posted December 18, 2015 Author Share Posted December 18, 2015 Hey guys i haven't been on in a while (computer is acting funny) but thanks for the info there is alot of good stuff here to look into, Steve sorry i know there is alot of info out there already but i do think this is a evolving topic, new products come out, people try something new that changes their opinion ect...but you are right there is alot of info out there. Bigfoot, thanks your imput does make alot of sense your right the grinding i have done 80-90% of it is on the lower belts originally i was suggested to get ceramic (vsm) 80's then 120 and 220 zirc/alumina (blue fire) and 400 hermes AO then he told me above that try what i want but they not needed and that right being a beginner i am not making knives for profit or to put into peoples collections where they would need to be polished....you advice matches that and i am going to get mostly the same i am just curious about others and i keep reading about the gators Quote Link to comment Share on other sites More sharing options...
basher Posted December 29, 2015 Share Posted December 29, 2015 I would advise using the best belts you can afford, and use them only when they are sharp. This can mean a quite steep belts per hour rate. My standard belt progression is 24 grit zirconium pre Ht and 36, 120 240 400 grit ceramic post Ht. I have been experimenting with leavers and other ways of applying body weight to the grinding as most of the modern belts we use are designed for a much higher material pressure and feed rate than we can realistically apply with hand pressure. I have found that my grinding rates have doubled and belts last about 3 times longer. Quote Link to comment Share on other sites More sharing options...
Kozzy Posted December 30, 2015 Share Posted December 30, 2015 34 minutes ago, basher said: I would advise using the best belts you can afford, and use them only when they are sharp. This can mean a quite steep belts per hour rate. My standard belt progression is 24 grit zirconium pre Ht and 36, 120 240 400 grit ceramic post Ht. I have been experimenting with leavers and other ways of applying body weight to the grinding as most of the modern belts we use are designed for a much higher material pressure and feed rate than we can realistically apply with hand pressure. I have found that my grinding rates have doubled and belts last about 3 times longer. The pressure issue is an interesting one. I tried to do a little research and there is not much to work from that isn't heavily generic. One thing that popped up which implied higher pressures are a good thing is how they are rated: It seems that the rating is generally expressed in how many HP you "suck up" with the pressure you apply (my interpretation). Minimum was about 1/2 HP per square inch being cut---on a 2" belt (common), that means you will stall most smaller grinders too easily to use the belt as effectively as you should. Amount of pressure was also highly related to backing material. Stiff belts were for the higher pressures and flexible belts better for low pressure grinding (according to 3M). Friability is the issue. Too little pressure and you are not breaking and exposing new cutting edges on the belt. That worn out belt may actually just need to be hit hard to cut like new again. In any case, the subject is interesting to me. If anyone has or can find better references to pressure....preferably in actual pounds applied rather than the amorphous HP that tends to be used, I'd like to hear about it. It'd be nice to know if there are comparative results for belt life or material removal per minute based on tests just to see how it all affects the process. My little belt grinder aint even close to strong enough to apply the pressures I should be using. Dang thing stalls if you sneeze hard at it. Quote Link to comment Share on other sites More sharing options...
the iron dwarf Posted January 1, 2016 Share Posted January 1, 2016 I am thinking of making a 2 by 72 or similar, is there a belt speed I should aim for or range of speeds Quote Link to comment Share on other sites More sharing options...
basher Posted January 2, 2016 Share Posted January 2, 2016 The optimal speed for my ceramic belts is supposed to be 10 to 15 Metres a second, I find that I prefer around 8 metres a second although I am experimenting with faster speeds. low end will depend upon what you are doing . 0 to 15 metres a second should cover most bases. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted January 2, 2016 Share Posted January 2, 2016 Presumably too slow and you risk digging in or setting up chatter... Alan Quote Link to comment Share on other sites More sharing options...
the iron dwarf Posted January 2, 2016 Share Posted January 2, 2016 thanks basher Quote Link to comment Share on other sites More sharing options...
metalbender Posted January 14, 2016 Share Posted January 14, 2016 buy the best you can afford and treat them like their free, try to use ceramic for hogging (36-40grits), zircs or ceramics to 120 then 220 after. i prefer hermes and nortons, i run fast powerful machines, Ive got 4 pheers with 1.5 to 3 hp motors depending on the machine, my hogging machine has a 6 inch drive wheel. preferred grits are 36-40 for hogging, 120 and 220 for cleanup, on my hollow grinder im then using 400 then 600, everything else im straight to abrasive stones. no buffers allowed in my shop, im deathly afraid of them. for what its worth I do both production, semi-custom and bespoke, average weekly production is about 40. hope any of this helps. Quote Link to comment Share on other sites More sharing options...
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