bench grinder - advice please

sarabande

sarabande

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I've never owned a bench grinder in my life, and was given one last week.

Here it is, well bolted to a workbench with 4 x 8mm bolts. I have downloaded the Clarke/Sealey instruction booklet for 6 inch grinders (it has a coarse wheel and fine one) so will adjust the tool rest and guards so that they move and fix as required. (The syringe is being used to soak the bench in water to reduce the fire hazard from sparks.)

I have goggles, gloves, and a large amount of trepidation about using it.

Can any "proper" user tell me if there is anything else I should do to make it safe to operate please ? Any pointer to a site which shows idiots how to use a grinder would be welcome.

many thanks

PS. I promise to clean the bench area before using it !
 
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Can't see the safety goggles anywhere! (Edit: reminder to self - read original post carefully before replying! (Though it is a point which bears repeating.))

A few minutes at the machine with someone who knows what they are doing will get you there much faster than reading about it here or in a book. Thinking about what you might want to use the grinder for - sharpening / re-shaping tools, sharpening drills, tidying sawn end of bolts, etc - might help to make this time even more profitable.

A useful tool alongside, but not replacing, a conventional oilstone.
 
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What are you trying to sharpen ?

They are simple to use and not scarey at all . The top gaurds look like they are missing the perspex flaps that stop sparks flying everywhere but they are not much cop any way .
Just set the bottom rest so your tool sits on it and gives you the angle you want on the stone . Use the whole stone by moving the tool over it , dont let the metal get to hot or youll ruin the tool .
 
bench grinder

Keep a can of water alongside to dip tools etc. in to keep them cool and prevent them 'burning'.

Only use the rims to grind with - never the faces, except for sharpening pencils at which they are very good !!
 
I know it is frowned upon here, but this things can bite hard.

It would be wise to go and look at the shortform use of Abrasive wheels which will tell you what type and grade to use on what materials.

http://www.hsa.ie/eng/FAQs/Abrasive_Wheels/

One of the best uses is to get a polishing wheel kit for it. You can really get a lovely finish on your prop then! (anorak).

http://www.thepolishingshop.co.uk/acatalog/Standard_Polishing_Kits.html


Make sure the tool rest is well adjusted so that what you are grinding cant be snatched into the gap between the wheel and the rest.
Also, let the wheel do the work, dont force it, or you will put a groove into the wheel and overload the motor.

I agree you will need a wheel dressing tool, but get the right one for what you have mounted.

PS: Its unlikely you will need the syringe to put out the bench fire, but it is useful to have a small paint tin of water to cool things down with (but remember you may embrittle the item by doing that (tempering and hardening).
 
The advice I was given was to gradually steepen the angle of attack until a fine line of sparks could be seen along the cutting edge. It is very easy with power grinders to grind the bevel and leave the edge blunt.

p.s. I can't speak from experience on the spark thing as I use a water-bath wheel - no problems with destroying temper.
 
Tap the wheels, they should "ring". If they don't ring they may be cracked, so replace them. The ring is quite dull, but a ring none the less.
 
FullCircle said:
Make sure the tool rest is well adjusted so that what you are grinding cant be snatched into the gap between the wheel and the rest.
Click to expand...

No more than a 3mm gap should be ok. Try not to get your fingers into that gap when you are holding something that you're grinding. If its small use a pair of molegrips to hold it.

You may find that the sparks are quite good for starting fires if you have it mounted on a wooden bench. Not to say you mustn't do it but just keep an eye on it.
 
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Actually I prefer a single point diamond dressing tool to true up the wheels.

You simply put in on the tool rest at 90degrees to the wheel edge and roll it back and forth across the tool rest with one finger, allowing it to recut the wheel edge as the grinder spins. Quite expensive but last a lifetime, quite literally. Grinders have quite soft wheels by comparison with an angle grinder and groove or deform easily and then whatever you are trying to grind "chatters" against the wheel. For smooth operation, dress regularly.

They are like a steel pencil stub, see here: http://radionics.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2439680

Your grinder is for light work, wood chisels, drills, cutters etc, for bolsters and cold chisels use an angle grinder!

Actuallly, for wood chisels and plane irons I use a linisher but an belt sander inverted in the vice is also good!
 
That is totally irresponsible

[for bolsters and cold chisels use an angle grinder! ]

i know a sparkie who done that & the disc in the angle grinder exploded into his arm. he was lucky not to loose the arm.
A Grind wheel is the tool to use
 
sailorman said:
[for bolsters and cold chisels use an angle grinder! ]

i know a sparkie who done that & the disc in the angle grinder exploded into his arm. he was lucky not to loose the arm.
A Grind wheel is the tool to use
Click to expand...

Was he using a cutting disc, by any chance? Because they are so thin they really hate the sideways forces you get when grinding. A proper grinding disk, carefully used, should be fine - although a bench grinder is definitely better.
 
orbister said:
Was he using a cutting disc, by any chance? Because they are so thin they really hate the sideways forces you get when grinding. A proper grinding disk, carefully used, should be fine - although a bench grinder is definitely better.
Click to expand...

Sailorman, it is NOT irresponsible, it's "horses for courses", naturally, use the proper wheel though. And yes, I've done the usual Abrasive Wheels courses!

A fettling wheel, the dpc (depressed center) type, is best for cold chisels, you really do not want to knacker the dressed face of a grinding wheel on such crude stuff unless of course you aren't wanting to hone up proper edge tools at any time. Besides, most bench grinders simply don't have the oomph for cold chisels, they just slow the machine revs down. A bench grinder is for more fine and subtle work. Of course, the proper way, not readily available to most home workshops, to sharpen cold chisels and the like is in a forge
 
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FullCircle said:
I know it is frowned upon here, but this things can bite hard.

It would be wise to go and look at the shortform use of Abrasive wheels which will tell you what type and grade to use on what materials.

http://www.hsa.ie/eng/FAQs/Abrasive_Wheels/

One of the best uses is to get a polishing wheel kit for it. You can really get a lovely finish on your prop then! (anorak).

http://www.thepolishingshop.co.uk/acatalog/Standard_Polishing_Kits.html


Make sure the tool rest is well adjusted so that what you are grinding cant be snatched into the gap between the wheel and the rest.
Also, let the wheel do the work, dont force it, or you will put a groove into the wheel and overload the motor.

I agree you will need a wheel dressing tool, but get the right one for what you have mounted.

PS: Its unlikely you will need the syringe to put out the bench fire, but it is useful to have a small paint tin of water to cool things down with (but remember you may embrittle the item by doing that (tempering and hardening).
Click to expand...
Had a cracking grinder in the workshop in Angola, I wondered why I had to continually dress the coarse wheel. The I caught the welder, he was ramming a welding rod in to it to get it red hot to light his ciggies!
Stu
 
orbister said:
Was he using a cutting disc, by any chance? Because they are so thin they really hate the sideways forces you get when grinding. A proper grinding disk, carefully used, should be fine - although a bench grinder is definitely better.
Click to expand...
I have an angle grinder permanently fitted with a rubber backing disc and a 24 grit paper disc. It is intended for grinding GRP but also serves very well fro sharpening bolsters, spades etc. I find it easier to use than the solid grinding disc.
 
Bench Grinder

Just get into and use it. It will be much safer than an angle grinder.
If it is old you may find the edges of the wheels are not flat but perhaps have a groove or low area in the middle. This doesn't matter so much if you are just grinding or smoothing metal. Move the job from side to side and with use you may get it flatter. If not then you might need the dressing tool. You need it flat for drill bits. New stone wheels are not so expensive and can be bought for all sorts of jobs.

Sharpening drills is easy. The trick is to start with a large drill 8 or 10mm that is in fairly good condition. Look closely you will see the cutting edge and angle. You grind the whole face ie edge and angle to improve the cutting edge. Note that the cutting edge must extend right out to the outside edge. They often wear on the outside where they have been used to make a hole bigger. The grinder will take a lot of metal off quickly so just a short touch then check. Keep the drill cool as already said by dipping in water.
good luck olewill
 
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