Carbide Lapping Grinder and Carbide Scraper
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- Опубликовано: 14 ноя 2018
- Having made up a carbide scraper I wanted to improve the grinding and honing consistency to spend more time scraping and less time at the grinder. With a very limited budget I set about cribbing the design of Robin Renzetti. All done for less than £60.
Okay, this may sound a bit out there, but I use ceiling fan motors to drive low speed diamond wheels (and diamond-impregnated MDF laps) to sharpen my woodworking tools and all sort of other things. I also use it to do other things like resurface 3-inch diameter balls (don't ask), although, a 14lb 10-pin bowling ball was a bit too much to ask. I was considering buying a Work Sharp WS3000 but decided it was overpriced, too noisy, and a bit so-so. Nevertheless, I liked the idea of the workstation and so mine is similar, runs horizontally as well, and uses various jigs to set angles etc, but uses the fan motor in direct drive for power. Essentially, it is the fan motor with a plate that attaches where the blades usually attach, this plate mounts a shaft with the backing plate, the diamond wheel, and the retaining screw, nothing else apart from the simple motor mount, the jigs and work surfaces, a mounting board, power cord, and box to hold the wiring and forward/reverse switch. Depending on the fan motor, the mounting can be made easier by pulling the motor apart and turning the shaft end for end, although you may need a lathe for this modification. >>:-)>
The fan motor runs slow, usually a bit under the mains frequency divided by eight (for 50hz about 380 to 400rpm), the speed being set by the number of poles in the motor and the amount of synchronous slip (load dependant). These motors are very quiet and with a bit of thought you can work out a suitable mounting system for the diamond wheels, mine are quick change on the backing plate using a simple knurled machine screw to hold the diamond plates in position. You could use a fan speed controller to further slow down the fan, the most common ones use extra capacitors, but there is a catch, they change the speed by using the capacitors to reactively reduce the current to the motor and thus the torque. This works in a fan due to the constant load of the fan blades, but not so with the grinder, it will still reach full speed but will just slow down more when loaded. I don't bother, although, I do retain the forward/reverse switch which can sometimes be labeled as summer/winter and is usually mounted on the fan itself.
The motors do not have much power and are easily slowed or stalled, this is good, you should use very little pressure on the diamond wheels, or you can shatter the diamond dulling the cutter or at least making it a finer, but inconsistent, grade. This is why many slow-speed, high-quality, wood turner, sharpening wheels use CBN. CBN is almost as hard as diamond but is far less likely to shatter, that is, you can abuse it more and get away with it.😁
In my case, the lower power forces me to be kind to the diamond wheel, grinding being one area where my usual care, thought, attention to detail, and perfectionism gets shown the door by frustration and (argghh) grinder dust.
Looking good Matt, you can do the flat faces of the scraper blades just holding them flat on the spinning diamond disk freehand. Its a little faster than stroking them on the flat plates.
ATB, Robin
You are everywhere,aren't you?😉
I learn a lot from you Robin. You are an excellent teacher.
@@xmachine7003 Thank you!
Nicely done, I did the same modification a month ago and it works perfect for sharpening my carbide scrapers
Thanks for commenting and watching. I am a little surprised at how fast it removes carbide stock compared to the Green Carbide stone I have been grinding with. far less mess as well.
nice work Matt as always enjoyed
Hi Matt, It would seem that this is a very good idea! I use the same low speed grinder, been using it since January, I didn't take it apart, I use it with a steel plate as backing for a cheap 600 grit diamond thin plate in place of the stone!. I kept the "water" tub and fill it with paraffin (Kerosene) this clears the diamond disk nicely and means that you can use it for high speed steel as well! All the best, Matthew
Nice job! You are inspiring me to make a scraper. I Have carbide grinders and you should be careful not to breath in the dust - wear a mask - the carbide will stay in your lungs.
I agree completely about the dust off of carbide scrapers - one of the reasons I like these slow running laps - they dont spray dust around. You can see it build up on the top face of the blade a small amount below the disk. I squib of wd40 or windowlene as a cutting lubricant also kills the dust. Compared to the green stone on my bench grinder this system is so much better. You take off so little material each regrind.
Have you tried spraying the wheel with glass cleaner, here we call it Windex, to mitigate or eliminate the dust?
Awesome! Very similar to how I made my scraper and slow speed grinder. There must be something right about it! Keep up the good videos
well one of us for sure got something right :-) Thanks for watching and taking the time to comment. All the best Mat
Nice job Matt👍. I need to build me a slow grinder.
Nice setup.
thanks for stopping by Randy.
Hiya Mat, I must take a moment to commend you on being so driven! You serve as an inspiration to a lot of people. Might i recommend a guy called Dale, he has a RUclips channel called build something cool. He also build a cabide sharpening machine recently. Keep the videos comming, and thank you for sharing!
Ps I got hold of a sandvik and a biax with some unused carbide a short while ago, soon I will be scraping away!
All the best Bud.
Hi Ian, now that chap Dale has a far better quality of scrap than I have access to :-) I was at the same kind of thoughts for my own lapping station when I watched Robins video and thought that would be a simpler solution. What I can add - at c 80rpm the #600 grit disk is very fast at removing carbide - I imagine at the speed Dale has his running it must be an order of magnitude greater - or perhaps he is using a much finer grit ? I will have to watch again and see. When you get set up to scrape - do make sure you have a sharp carbide in your hand scraper - try that first before the biax. once you feel it cutting properly you will soon know when the edge needs dressing - I suspect with a biax its not as sensitive and you would just push harder ... something on my list of things to learn.
@@lookcreations Great job, I have been looking forward to this vid since I saw it on Instagram. Is that the RPM of this grinder, 80? I made one a while ago using pulleys at about 175 RPM. When I was looking at those crazy expensive Glendos I'm pretty sure they were about 200 RPM so I just tried to get close to that. Also I added on one of those cheap lil' coolant spray misters and it helps immensely with swarf clearing and wheel life. Thx Mat
When I get a chance I will get a rev counter on the spindle - but its pretty close to 80 rpm. When I was looking at making one from scratch - I was thinking anywhere between 100 & 150 rpm would be fine 200 rpm max 50 min so quite a big window ! What I do like with the slow speed is there is very little 'fling' or either debris or ground powder - the bench grinder with the green wheel is bloody messy and thats a pain when scraping as you know. If the worm gear wears prematurely I may well learn how to cut a new worm and wheel and could change the rpm .... but for now its fine :-)
I just bought an ''SIP'' branded one off tool station for £56. Same grinder with the plastic body just different color. I really want to have an actual ceramic lap for it like Robin Has.
There isnt really a bid advantage in a ceramic lap - they are easy to damage and very hard to repair / reface. A diamond lap is cheep, can be replaced /swapped for differenat grades. If I recall - Robin had the lap and just used it. Be interesting to know if he had to do over would he use a diamond lap or buy a ceraminc ? thanks for stopping by and commenting. All the best Mat
@@lookcreations I think Robin's intention is to mirror lap the cutting edges of carbide and CBN tools that he grinds on his surface grinder or tool grinder with something like 3 or 1 micron diamond. I don't think you can get these plated diamond disks that fine can you? But I will still like the ability to put one of these plated disks on for controlled material removal, for shaping nose radius of tools etc. The grinder (exactly the same as yours) arrived. Just need to mount a ceramic disk I bought a while ago (not specifically sold as a lap, just a circular 8 in ceramic disk I went to the ends of the earth to find for around £55)
Originally I thought of making the Version how Steffan did it with the 24 DC Motor
But just the Motor might be more Expensive than some used one of these :p
Maybe a additional 230V Speedcontroller.
Btw... nice seeing your Kid Brazing
Get there Hands greasy as early as Possible 😁
So much stuff I learned from my Father I still use...
To many 30is Guys who can't even fix there own Bicycle u_U
Honestly you don’t need a speed control, anything below 150 rpm. You can put a course grit disk on for faster stock removal or work at the perimeter. It’s done me proud so far. It could be improved with a better tool support and interchangeable angled plates…. But for general use on carbide scrapers it’s been fine. A lot better than green stone on a bench grinder. My kids get involved with most of what I do. It’s a good way to spend time together and they learn. Even if it just helps them appreciate handskills and trades for what they are. You should take a look at the early Clanger 109 videos where they help take a Landrover apart- or the cottage renovation No4NextDoor- they get stuck in. Thanks for watching and commenting. All the best Mat
Mat, I have 5 filing machines like yours but none of them seem to work very well. Any suggestions? Keep up the good work. Craig
Hi Craig, they are bloody tricky mate ! Im still trying to work out what the little fella is after :-) xmas is not so far away and all that - Im sure he has some long term strategy to gain favour ! On the other hand both my two have always gotten involved in my crafts - I recall their mothers shock seeing them sat astride a heavy chestnut board both pulling a razor sharp draw knife toward themselves smoothing the surface. I think they were 8 & 6 at the time .... no accidents and they gained an appreciation for green woodworking. Its going to be fun when we get teh forge up and running and they start metal thumping red hot steel ! :-)
@@lookcreations I know what you mean, my brood's mother thinks there is something wrong with 10 year olds helping pour molten aluminium. I say, they've got to start some time. Several of my boys enjoy being in the shop but they don't want to help me, they want to do their own projects. My oldest had a 1970 Volvo stuck half way into the shop for over a year whilst he tried to figure out how to stuff a Honda S2000 engine in it. It was a riot to drive when done but I spent a winter with the big door half open. Keep up the good work and keep us to to date. Craig