Angle Grinder Sharpening Station

[forexpipz]

It would seem that there is endless science regarding grinding and sharpening. Enough to make you anxious to the point of sheer frustration. With that aside I decided to take the plunge and build my own system.

I began by hand grinding a primary bevel on 60 grit sandpaper using a Richard Kell Number 3 MK2 honing guide. This gave exceptional results but doing this for any length of time will destroy your soul completely. It takes HOURS and hurts like HELL!

Although I feel like my bones have de-mineralized through RSI - I really like the simplicity and low cost of paper based abrasives. They open up endless configurations for metal shaping.

I was going to buy a belt sander and grind the primaries vertically but after doing extensive research I decided not give my money to the Chinese and build my own set-up. OMG - even my beloved BOSCH has iron curtain origins!

Anyhow. Here is what I knocked up the other day.

Please let me know what you think.

Cheers.

 

[MickCheese]

I think...... Be careful.

Someone I know had a very bad accident with an angle grinder blade and nearly lost his hand. From that moment I always keep both hands on the grinder.

OK it was a diamond blade and he was cutting a floor tile by holding it in one hand with the grinder in the other when it snagged and ran across his wrist cutting an artery but I suppose the chisel could get snagged and snapped sideways.

That really is literally 'scary sharp'.

Mick

 

[forexpipz]

I was terrified at first. The grunt and power of the grinder is something I'm totally aware of. I've seen the pics. Its horrific what grinder accidents can do.

This system will be very safe once I make the riding surface planar with the blade. Fingers will only ever contact the surface which may result in a burn at worst. What you cant see from the image is that the grinder is held down with a 20kg ballast and doesn't move at all. Hope this alleviates any concern.

The results are spectacular and very quick. The guide takes away all the guesswork and gives accurate results. You can either touch down or ride back and forth. I prefer the touch down. Heat build up is not even noticeable if i retract often enough.

Another point is that you can close the box. Flip her over and use the other side of the wheel. Voila. Instant grit change with no messing...

 

[Jacob]

I've done same with angle grinder but clamping the blade over the edge of a bench and applying the angle grinder hand held. Works really well except you have to be very careful if you want a nice straight flat bevel. Safe as well.
Belt sander does it better and neater.

 

[forexpipz]

I've done same with angle grinder but clamping the blade over the edge of a bench and applying the angle grinder hand held. Works really well except you have to be very careful if you want a nice straight flat bevel. Safe as well.
Belt sander does it better and neater.

The belt sander is definitely the way to go. With this set-up you get all the benefits of a belt sander without the need to have loads of expensive belts.

 

[Shrubby]

All of the benefits of a belt sander - Really?
Sand a table top flat with it
Good belt sander inverted with a fence or frame with a home made 25º jig screwed to it

Matt

 

[forexpipz]

All of the benefits of a belt sander - Really?
Sand a table top flat with it
Good belt sander inverted with a fence or frame with a home made 25º jig screwed to it

Matt

When I said benefits I was refering to the sharpening benefits. lol.

 

[MickCheese]

Well, it's definitely a novel use for an angle grinder.

Mick

 

[blurk99]

do be aware that many grinder discs are specifically for edge cutting, not side grinding and pressure will cause them to flex and let go with a hell of a bang...
neat idea though - could you adapt the disc guard (that's presumably removed and lurking in the case...) to attach it to the outside of the carry case under the blade?

jim

 

[forexpipz]

do be aware that many grinder discs are specifically for edge cutting, not side grinding and pressure will cause them to flex and let go with a hell of a bang...
neat idea though - could you adapt the disc guard (that's presumably removed and lurking in the case...) to attach it to the outside of the carry case under the blade?

jim

Hey Jim. The blade guard is still attached inside the box. As regards to the pressure it really is the lightest of touches. The thing spins so fast it removes material very quickly with minimal contact.

You really don't need to press the chisel down at all. Just lowering it suffices. I would hazard a guess that cutting with this disc causes more stress than barely touching down upon it with the Kell guide.

When the box is closed only part of the disc is exposed and once I cut the radius of the disc on some plywood that is co-planar with the disc then all I need is some sort of overhead perspex to make this system very safe. Hell. I might even use a piece of 6mm plywood instead.

Full face protection for the time being.

 

[No skills]

Well this is a can o' worms, I sharpen any bang and crash tools at work on a 9" grinder.

Dont assume its safe - ever. I've seen 16+ stone men thrown from ladders by 9" grinders when the disk bites, ducked and dodged broken disks as they fly off the grinder - even had one bite and come out of my hands, do a complete 360 in front of me (with the lead knocking off my face shield as it span) and land on my boots.

But thats enough health and safety #-o

Its very easy to overheat what your sharpening when doing this so look out for that, very easy to grind out of square. The grit on the sides of the disks wont last long (assuming your using a cutting disk, grinding disks obviously have loads more) before your through to the mesh.

Yes its very quick but I think its a bit barbaric unless the tool needs a complete reshape, I wouldnt use it on anything I liked

All this is IME and IMO, no offense is ment - but please be careful.

 

[forexpipz]

Well this is a can o' worms, I sharpen any bang and crash tools at work on a 9" grinder.

Dont assume its safe - ever. I've seen 16+ stone men thrown from ladders by 9" grinders when the disk bites, ducked and dodged broken disks as they fly off the grinder - even had one bite and come out of my hands, do a complete 360 in front of me (with the lead knocking off my face shield as it span) and land on my boots.

But thats enough health and safety #-o

Its very easy to overheat what your sharpening when doing this so look out for that, very easy to grind out of square. The grit on the sides of the disks wont last long (assuming your using a cutting disk, grinding disks obviously have loads more) before your through to the mesh.

Yes its very quick but I think its a bit barbaric unless the tool needs a complete reshape, I wouldnt use it on anything I liked

All this is IME and IMO, no offense is ment - but please be careful.

I agree with all what you have said especially the barbaric nature of what i'm doing. Thing is I'm limited on funds and have to use what i got lying around.

I've reshaped some horrible chisels with it today and the grind is very good. Using extremely light touches I'm able to lower the chisel down ever so gently and i guess this is in part due to the exceptional accuracy of the Kell guide.

If i could reduce the speed of the grinder down to a 1000 rpm I would be a happy man but the controllers are like 60 quid to do so. Pointless considering a belt sander can be had for much less from ebay.

 

[No skills]

I certainly understand the limited funds and making use of what you have

If your after something else cheap for sharpening keep an eye on lidl/aldi stores, now and then they will have a 4 sided diamond stone (4 different grits) for £10 or less. Not saying its the flattest thing or will last forever (cos its possably not and wont) but its doing me for now and cheap enough not to worry about when its time to bin it.

Best of luck.

 

[forexpipz]

Well after using it again today I decided it was just too much of a risk. I spend more time thinking about it exploding in my face. Does anyone know how to attach a wheel to a smooth shaft of an ac motor

 

[blurk99]

they have a proper name, RS and maplin used to sell something.... tight fitting sleeve and a couple of grub screws? look at the axminster website / grinder polishing adaptors etc.... maybe something in there you could use

jim

 

[blurk99]

oh - saw this on another site and thought of your sharpener...

http://www.mig-welding.co.uk/forum/show ... hp?t=29590

don't click the links in the first post if you're squeamish

jim

 

[forexpipz]

Well its final. I'm not using this grinder to dress any iron or put bevels on. Its just too bloody scary. I think the noise contributes a lot to my fears but I have seen the pics and i have decided i want to live a little while longer.

I'm ordering a Norton Silicone Cabide bench stone 3" wide that will form the primary in minutes with a little elbow grease.

Over at

http://www3.telus.net/BrentBeach/Sharpen/sharpen.html

The guy has spent seven years researching how to form the best edge and i think i'll take his advice. His findings all though not scientifically proven are good enough for me and the stone costs a whopping 17 dollars US.

 

[snikolaev28]

Hmm...
At first excuse me for English, I'm Russian speaking person.
Today just returned from Moscow, it was a business trip. There, in Moscow, live my friend, he has a small house in the Moscwo suburbs and right now this house need a repair. Mostly woodworking repair.
Just because this friend of mine has enough money to hire carpenters he did this. Mostly they a Tadjiks, not rich country so they need go abroad and work for money. Their families lives for those moneys.
I have had obly one question to my friend, which is the way to know qualification (workmanship level) of hired carpenters-Tadjiks.

The explanation is cute, simple and very short - "Look, all of them has ONLY 4 or less fingers on one hand or on both hands. It means that they worked with tools and have enough workmanship level to repair my house".

I think that using such angle grinder as a sharpening station is the right way to improve level of workmanship but from the other part a way to obtaine visible sign of such qualification.

 

[Hudson Carpentry]

Tell you what. I have both small and large grinders. The large grinder scares the hell out of me and im not the type to get scared when using tools. I have only used it once to cut a door into a brick wall. It kicked loads of times (brand new diamond bosch blade), I was worried to hell that it would cut through my leg as thats where it kept kicking out towards. Finished the job, wiped my brow and put it away, out of sight hehe.

I use a grinder where a grinder is required there not tools I tend to miss use.

 

[Mark A]

My 9" grinder is the one tool I respect more than any other I have, as I've seen the pictures and potentially had quite a bad accident happen to me. The guard on the last one I had came off while I was using the grinder; it fell onto the diamond blade, bounced around and then was fired straight at my neck. I'm fortunate I didn't let go of the grinder while it was still running as it would probably have removed the fingertips from my right hand and then fell onto my leg. Still gave me a nasty bruise and a funny voice though!