Surface grinder stone help

[RobonthemoorParticipant @robonthemoor]

Stone type

[RobonthemoorParticipant @robonthemoor]

Al & I have a Jones & Shipman surface grinder, with it came a large amount of wheels, we have not got an idea which wheels do what, can any one advise use. I have an ally cylinder head to skim! So advice on that would be appreciated. See photos of a small sample, and why is the one stud up two different colours.

rob

[Sub MandrelParticipant @submandrel]

It's a special used for tidying up the edges of bimetallic strips used in thermostats.

As for grinding aluminium, good luck!

Neil

P.S. We aren't allowed to call it ally anymore, apparently, at least not round here. Not sure when in the last forty years this rule was applied

P.P.S. a google search for ALLY and Aluminium returned one and three-quarter million hits!

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

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

[GoCreateParticipant @gocreate]

Hi

Norton provide free courses if that interests you.

As far as I know surface grinding of aluminium is not common.

Probably a general purpose silicon carbide wheel, the problem will be that aluminium will tend to clog or load the wheel, lots of coolant should help, keeping the cuttings cool should help prevent clogging.

Experiment on some similar scrap first.

Nigel

[GoCreateParticipant @gocreate]

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

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hello again ,

Got called away when editing above reply so a bit missing :

Aluminium can be ground successfully but it is a specialist process and very dangerous if not done with proper understanding .

As regards an Aluminium cylinder head a very fine milled finish using a broad sweeping flycutter would be just as good and much safer to do .

MikeW

[Steamer1915Participant @steamer1915]

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

[Anonymous]

The grinding wheel that is stood up is two different colours because it has been used on only part of the width, and the part that has been used is glazed.

It may seem a waste, but I'd bin the wheels that came with the grinder and buy new. Presumably the wheels are an unknown quantity, so you don't know how they have been treated or stored. As a rule of thumb the periphery of a grinding wheel should be doing about 5000 feet/min, that's around 60mph. If the wheel breaks up it'll do a power of no good to anything in the way, including you.

Andrew

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

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 .

[mickParticipant @mick65121]

Fly cut the head on the mill, its the best and safest option.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

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

[Rik ShawParticipant @rikshaw]

Aluminium does not lend itself easily to being ground. It makes me wince even thinking about it – cast iron certainly, but ally? – NO. I will go along with the fly cutting on the mill advice from Mick, its the only way I have ever done it or seen it done.

Brush on some paraffin (WD40 might work as well) before starting the cut and provided the tool is ground correctly and the mill is trammed correctly you can expect a superior finish. If you do it right the mill will tell you so with a hiss from the tool as it cuts.

Rik

[Steamer1915Participant @steamer1915]

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.

[colin hawesParticipant @colinhawes85982]

It is advisable to "ring" even new grinding wheels. I agree that the best way to skim Al. surfaces is with a very sharp flycutter.To be sure of flatness the flycutter should cover the width of the job in one pass and have room to run off the end This usually requires a large machine .If a flycutter is to be used it is vital that it is set truly square to the machine table or a concave surface will be the result. However ,I have never attempted to surface grind Al. Another possibility is a shaper Colin

[Anonymous]

Posted by Steamer1915 on 10/09/2013 13:32:17:

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.

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

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

(1) The world and his dog probably know that a suitable grinding wheel can be used on the side if properly dressed and set up but this doesn’t alter my advice to Rob to put the actual wheels shown in the picture in the bin .

(2) I always give a thought to the skill and experience level of the OP when answering questions about machining :

Someone like Graham for instance is trained and experienced so he can work out his own procedures , identify any difficulties for himself and take or leave any advice offered .

An inexperienced home workshop man on the other hand is often completely in the dark to begin with and can be faced with a barrage of contradictory advice . I think myself that it is best in this situation to offer only simple safe solutions .

Surface grinding of Aluminium by anyone that does not understand the difficulties is dangerous and not recommended .

Regards ,

MikeW

[jason udallParticipant @jasonudall57142]

Ali..plus rusty iron

Sounds like thermite

[RobonthemoorParticipant @robonthemoor]

Ok fly cutting the head it is, ALS bringing one over tomorrow as the one I have is home made & I have not used it ! Came with the mill. Why use kero or wd 40 & not cutting oil ?

rob

[MuzzerParticipant @muzzer]

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

[Gordon WassParticipant @gordonwass]

Years ago we skimmed cyl. heads on a specialised grinder, a flat iron table with a horizontal segmental wheel. The casting pushed over the table by hand and the wheel raised until cutting started. Used for iron and alloy heads, no coolant. These little jobs were "government work " so may well not have been the correct way.

[RobonthemoorParticipant @robonthemoor]

Thanks gents, carbide tip was best result, please see photo.

rob

[Author]

Posts