I've got lots of dull and chipped carbide mill bits. I also acquired a collection of diamond grinding wheels. Seems the wheels have little effect on dull carbide mill bits. I don't know much about diamond wheels. I'm afraid if I press too hard I'll scrape the coatings off the steel backers. So the question is, how does one use a diamond sharpening wheel to sharpen carbide.
Need tips about sharpening carbide cutters.
- Thread starter jpeter
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Help Support Home Model Engine Machinist Forum:
when using the diamond wheels you can only take a little at a time, only .0002or less at a time. they also need to be cleaned with a real soft white stone when it is running. you can not grind with a diamond wheel like you would with a regular grinding wheel.they willload up and also build up alot of heat. jonesie
You should find that a coated wheel for sharpening tungsten is run slowly and usually with water cooling. They are also usually known as diamond laps rather than grinding wheels, and are used mainly with brazed on tips for shaping and honing. If you have already used them like a normal grinding wheel, they are most probably now past their sell by date.
http://richontools.com/index.php?main_page=index&cPath=1_9
Diamond grinding wheels usually have an aluminium backer plate with a bonded on block of diamond impregnated carrier.
http://richontools.com/index.php?main_page=index&cPath=14&sort=20a&page=1
It is these that are used for grinding your tungsten tooling. Unfortunately, one of the drawbacks is getting them trued up after you have worn them away a little. For normal grinding wheels, you would use a diamond mounted dressing stick, for restoring diamond grinding wheels, you should really use a brake dresser, which uses an oxide bonded wheel to wear them away gradually and bring them back to true.
http://www.jubileemactools.com/website-pages/NORTON__No2__Brake_Dresser-p-398.html
This is cheap, a new one would cost over a grand. I got mine off fleabay for just over 30 squid, with a spare brand new wheel.
Or you could try to bring them back to shape using an Alox dressing stick, but that is a little hit and miss unless you can mount them rigidly and feed gradually.
These articles might help if you already have a surface grinder.
http://madmodder.net/index.php?topic=1428.0
http://madmodder.net/index.php?topic=1434.0
http://richontools.com/index.php?main_page=index&cPath=1_9
Diamond grinding wheels usually have an aluminium backer plate with a bonded on block of diamond impregnated carrier.
http://richontools.com/index.php?main_page=index&cPath=14&sort=20a&page=1
It is these that are used for grinding your tungsten tooling. Unfortunately, one of the drawbacks is getting them trued up after you have worn them away a little. For normal grinding wheels, you would use a diamond mounted dressing stick, for restoring diamond grinding wheels, you should really use a brake dresser, which uses an oxide bonded wheel to wear them away gradually and bring them back to true.
http://www.jubileemactools.com/website-pages/NORTON__No2__Brake_Dresser-p-398.html
This is cheap, a new one would cost over a grand. I got mine off fleabay for just over 30 squid, with a spare brand new wheel.
Or you could try to bring them back to shape using an Alox dressing stick, but that is a little hit and miss unless you can mount them rigidly and feed gradually.
These articles might help if you already have a surface grinder.
http://madmodder.net/index.php?topic=1428.0
http://madmodder.net/index.php?topic=1434.0
Joachim Steinke
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Hi Jim
If only sharpening is the aim, the wear of your diamond grinding wheels would not be that dramatic. If the cutting faces are not serious damaged or even broken away the abrasion of lets say 0.001in would do the job quite well. Really deep grinding would make things more complicated anyway. Removing a lot of material on the frontal clearance face minimizes the chip room in the dead centre region for instance. If you have to grind that deep you have to reconstruct the whole geometry of the front end profile, otherwise you will loose the rake face (and the chip room in the dead centre) more and more.
Grinding with fixtures on a moving table is a sliding process, so you dont push the tool with much force at the ever same position onto the wheel surface as you would do it while hand grinding your lathe tools with a normal bench grinder combined with a fixed tool support. And you only make small amounts of infeed with every pass, normally no more than 0.0001in at once. If you operate with care you will not groove the diamond wheels and dressing is not that necessary than you know it with corundum wheels.
Okay, to achieve commercial output quantities flood cooling would be a nice accessory, but you dont really need this for your home business. I dont have flood cooling and I use resin bonded and metal bonded diamond wheels as well on my tool and cutter grinder. And I couldnt notice serious temperature problems on the tools as well as on the grinding wheels.
Forget the second hand wheels and by some new one, and the grinding problems should be solved.
Achim
If only sharpening is the aim, the wear of your diamond grinding wheels would not be that dramatic. If the cutting faces are not serious damaged or even broken away the abrasion of lets say 0.001in would do the job quite well. Really deep grinding would make things more complicated anyway. Removing a lot of material on the frontal clearance face minimizes the chip room in the dead centre region for instance. If you have to grind that deep you have to reconstruct the whole geometry of the front end profile, otherwise you will loose the rake face (and the chip room in the dead centre) more and more.
Grinding with fixtures on a moving table is a sliding process, so you dont push the tool with much force at the ever same position onto the wheel surface as you would do it while hand grinding your lathe tools with a normal bench grinder combined with a fixed tool support. And you only make small amounts of infeed with every pass, normally no more than 0.0001in at once. If you operate with care you will not groove the diamond wheels and dressing is not that necessary than you know it with corundum wheels.
Okay, to achieve commercial output quantities flood cooling would be a nice accessory, but you dont really need this for your home business. I dont have flood cooling and I use resin bonded and metal bonded diamond wheels as well on my tool and cutter grinder. And I couldnt notice serious temperature problems on the tools as well as on the grinding wheels.
Forget the second hand wheels and by some new one, and the grinding problems should be solved.
Achim
