Overheating grinder

[Peter G. ShawParticipant @peterg-shaw75338]

Hi everyone,

 

Gordon & Ian. Thanks for that. It’s looking more and more that my machine is in fact ok. I have to say that I didn’t notice any holes through the armature – that is presuming your definition of an armature is the same as mine, ie the rotating bit in the middle.

 

Chris. I too had heard about the difference between older and newer files. So far, apart from the ones ruined in the fire, they seem to be old ones, ie solid high carbon steel. I do have some modern files which frankly are rubbish, and I do have an 8″ ½round one ready for experimenting on. It will require quite a bit of grinding/cutting to be able to get any useful metal though.

As for the SMEE bit, I think we’d better stop this. I mean let’s face it, “Erin” (‘ER In Doors) probably wouldn’t speak to me again if I did as you suggested. Mind you, on reflection, maybe not so bad an idea afterall!!!!!!

Regards,

 

Peter

[mgjParticipant @mgj]

Peter – with your wheels.

 

I hope I’m not teaching Granny, but for sharpening up wheels a star dresser is good and cheap. Might appeal to your supposed Yorkshire nature.

 

(On which note the lads from my regiment 13/18 Royal Hussars (QMO) all came from S Yorks – indeed my first tank crew almost all came from the same street in Doncaster. I didn’t notice them being particularly close walleted – well not when it came to going down the pub anyway)

 

Better I think is a flat diamond dresser because that will true up a stone as well as revive it. A single diamond is also pretty good and not expensive (we are not talking the Cullinan stone here) , but it really needs to be guided to remove grooves rather than put them in.

 

I’m still on my original wheels.

[Peter G. ShawParticipant @peterg-shaw75338]

Meyrick,

 

I do have a single point presumably diamond dresser and had been thinking about using it, but have also been wondering about how much I would need to take off to regain the sharpish corners. Certainly on the coarse wheel it would be quite a lot, say 3 mm. The fine one wouldn’t be as much, but due to drill sharpening using a Picador drill sharpening jig (there are others around very similar) the side of the fine wheel must be slightly concave. As a result, I’ve been considering changing the wheels anyway.

 

Two thoughts are some sort of cup wheel (I think that’s what they are called) and/or trying to use 6″ wheels rather than the 5″ as standard, but this size may put too much load on the motor. Any thoughts?

 

Also wondering about going diamond.

Regards,

 

Peter

[Chris KiteParticipant @chriskite65679]

Hi Peter,

You will probably find that you can buy a new bench grinder for less than replacement wheels. This of course leaves you with your old grinder to fit whatever type of wheels you desire.

 

Chris

[mgjParticipant @mgj]

Cup wheels are pretty handy – I have a couple on the Quorn.  You rotate through 90 deg, but I wonder if that offers any advantage if you haven’t got the rest of the tool and cutter grinder?

 

Diamond wheels I have no experience of.

 

Larger wheels – wise if it already gets a bit warm? I suspect, under load, it would run at less than optimum speed, and then you’d have to go back to where you were and fix all the guarding again.

 

I’d just take the existing wheels to where you need to go to get them right. See how it works. Buy wheels or not as you find after that.

 

The advantage of buying wheels is that you can get the grits you need for sharpening tools. The ordinary offhand ginder is normally fitted with tolerably coarse wheels – even the fine ones. So you could fit a really coarse reasonably loose gritted one for roughing, and then use a fine white 60grit for putting that mirror shine on.

 

Buck and Hickman amongst others do a range of wheels. Whether they are the best/cheapest, I don’t know. Universal is one well known make for tool grinding.

Edited By meyrick griffith-jones on 07/11/2009 00:03:26

[Ian S CParticipant @iansc]

Peter don’t put on larger wheels,your machine has barely enough power for what it has now,my 5″ grinder is 300w and I find that fairly minimal as far as power goes.I havn’t opened it up but I think it has a start winding and switching so it will run cooler,the shaded pole motor has a shorted turn of copper that tends to heat up these motors are only ment for light use.Chris is right,here in NZ the stones would cost about NZ$30/£10,I got my 5″ grinder for$25 hardly used.IAN S C

[MikeDParticipant @miked]

Just as a thought, the quality of the stones that come with the economy grinders are pretty poor, and as another poster has mentioned, a coarse loose gritted wheel for roughing, and a good quality fine white (or pink or blue) one for finishing is a big improvement to these grinders – as is a decent adjustable tool rest.

Keeping the stones properly dressed also helps immensely – either with a star type, or a diamond.This should be done really quite often – say after no more than an hour or so use, and if the grinder is in the same room as the machine tools, you should really cover the slideways before you start, this operation makes clouds of highly abrasive dust. That’s another reason to do your roughing out with an angle grinder, with the tool held in a workmate, and placed outside the shop when it’s not raining!!

[mgjParticipant @mgj]

Mike That’s very good point about machine tools, and I’m paranoid about the dust. All my grinders are in a different room ( where someone used to keep goats and still unrenovated lest it sound over grand)

 

Even a shower curtain or anything to keep grinding separate from oily tools is a great idea.

[Peter G. ShawParticipant @peterg-shaw75338]

Hi everyone,

 

Thanks for all the comments. Obviously more research and thinking by me required.

 

Regards,

 

Peter

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