Hi Rob ,

” I have an ally cylinder head to skim! “

(1) Best advice :

Absolutely definately don’t even try .

(2) Second best advice :

Go on a two year grinding skills course before even contemplating it .

Third best advice :

Get lots of private medical insurance .

Regards ,

MikeW

Hi

MikeW's post crossed mine, his advise is always very good.

Here's some info that might help. Reading through this I would be very wary trying. Mike W's advise probably very wise.

Nigel

You can grind aluminium on a surface grinder quite easily. The trick is to lightly smear the job with grease. This will stop the aluminium clogging the wheel and there will be a mini snow storm of aluminium swarf. Cuts of 3 or 4 thou are quite safe. Flooding the job with coolant doesn't work. An aluminium oxide wheel of 46 grit is quite adequate. There will be no sparks! Been there, done it.

Steve.

Edited By Steamer1915 on 09/09/2013 22:30:55

Yes – some of those wheels don’t look in very good condition and a couple of them are either badly dressed or they’ve actually been used on the sides for grinding .

Wheels are not that expensive – get a few new ones .

The professional grinders in industry could tell whether a stone was cracked by ‘ringing’ it – just like testing fine china – though a duller sound .

From a posting by Billy Mills a while back :

” The reason for not grinding Aluminium is that many people have been injured by trying to grind on a conventional bench grinder. The soft metal very rapidly cloggs the stone then can weld to the job so the stone can shatter and do a lot of damage to the people around the machine. The spinning stone has a lot of kinetic energy that gets released in miliseconds.

Specialists know exactly how to grind Alloys but they do it under carefully controlled conditions which are not available in the home workshop. “

MikeW

I would echo Gray's point about not grinding Aluminium on a pedestal or off-hand grinder. I would also agree that milling is a viable alternative.

Thanks to Gray's confirmation that it can be done on a surface grinder, I no longer feel a lone voice in the wilderness..

Reference has been made about wheels looking as if they have been used for grinding on the side. It should be appreciated that wheels can be used for side grinding as long as the wheel is dished and the cutting is done on the outer edge of the wheel. Wheels can be purchased that have the relief already dressed in, or the wheel can be relieved with a hard dressing stick such as Norbide etc.

Now that I've tossed that little hand grenade into the discussion, I shall put my tin helmet on.

Steve.

The manual for my Myford cylindrical grinder even gives you a handy sketch showing how to relieve the side of wheel for grinding up to a shoulder.

Apart from the aluminium clogging up the wheel on a off hand grinder I was told that grinding aluminium, followed by some innocent with a piece of rusty steel equals boom.

Regards,

Andrew

Ali..plus rusty iron

Sounds like thermite

I used a surface grinder to skim a cylinder heads years ago, under the instruction of the workshop tutor. This was partly a contrived excercise, as I had to attend various skill centres as part of my degree course and I had a cylinder head needing some attention. The alternative would have been a variety of std practice pieces I suppose. We used a non-aqueous coolant, possibly just parafin, to avoid clogging and achieved a pretty nice finish.

Apart from the safety issues mentioned above, the main reason for using a milling cutter rather than a grinder would be to ensure a sufficiently rough surface to key the head gasket to. I know know from my time in the automotive sector that a mirror finish isn't what you really want. There is an optimal range of surface roughness. My second cylinder head skim (also at a skill centre) was done on a vertical milling machine with a fly cutter and was a lot quicker and simpler. I'd recommend that approach!

Muzzer