Skimming head

[robwizard]

Got a spare head for my Amazon which I was thinking of rebuilding.. no reason really just cos I have a spare and would like to have a crack at it! It has a good bit of rusting on the various faces and after pressure testing it (seen some DIY methods I'm gonna try and copy..) I reckon it could do with a very mild skim. I have access to a couple of big milling machines and also a surface grinder. I have read mixed reviews on using normal types of milling machines for this kind of work but can't find anything about using the grinder? Might be a good shout?

Cheers

 

[BrokenBiker]

is it an ali head? grinding ali isn't a good idea unless you have a specific wheel for it. not sure if you can get ali grinding wheels for a surface grinder, I have only ever used them to grind steel. I think we had a wheel for the cutter grinder in work that is good for ali thoug

 

[awemawson]

Big vertical milling machine and a well balanced very rigid fly cutter is what you need to skim heads. Sweep of the fly cutter needs to exceed the width of the head, and machine X travel needs to be sufficient for the fly cutter to both start and finish 'off the job'

 

[BrokenBiker]

when I was in college one of the more annoying lads brought an 8v golf gti head in to skim as it was warped. he had spent the frst 2 months or so winding everyone up so while he was mid cut using the power feed, one of the lads that was very annoyed with him walked up and plunged the cutter into the head. he was using a 20mm end mill, it totally destroyed the head. moral of the story, lock off the z and y axis, use the right cutter and don't walk away from the machine while its cutting to annoy someone lol

 

[KemppiFrog]

My local guy used to skim heads on a his big lathe. Then because demand was high (lots of people using hard water rather than proper coolant in engines with ally heads) he bought a specific machine. It had a big fly cutter in a flat iron table, The head was dropped onto the area away from the cutter, then clamped onto a carrier. This carried the head across the cutter, with it set proud by whatever he figured needed taking off. Very quick, with minimal set up time. Not seen one since. Since I knew him quite well, he would do a head while I waited, around 15mins, or less. No need to even take the valves out for an ally head.
KF

 

[BrokenBiker]

My local guy used to skim heads on a his big lathe. Then because demand was high (lots of people using hard water rather than proper coolant in engines with ally heads) he bought a specific machine. It had a big fly cutter in a flat iron table, The head was dropped onto the area away from the cutter, then clamped onto a carrier. This carried the head across the cutter, with it set proud by whatever he figured needed taking off. Very quick, with minimal set up time. Not seen one since. Since I knew him quite well, he would do a head while I waited, around 15mins, or less. No need to even take the valves out for an ally head.
KF

we have those in work, just call them millers. ours are made by Cincinnati and are probably 60 years old. we can run them in the configuration you talk of, like a table saw essentially, as a normal milling arbour or as a grinder

 

[KemppiFrog]

we have those in work, just call them millers. ours are made by Cincinnati and are probably 60 years old. we can run them in the configuration you talk of, like a table saw essentially, as a normal milling arbour or as a grinder

Interesting, basicly, I don't spend much time in commercial shops, so probably missed them. At the time, around 25yrs ago, it was quite unusual. The other local machine shop was still flipping belts to get the lathes turning (S. Portugal)

 

[AndyStobbs]

Rob, I wouldn't even bother to mess about DIYing it. Drop it off at EJ Hammond Connors Quay, they can test it for you (forget the price but its reasonable) and then skim it if its servicable. Last time I got one skimmed (recently) it was £25 + VAT. You can literally earn the money faster than you can save it. They are top blokes, I get all my engine work done there.

 

[BrokenBiker]

Interesting, basicly, I don't spend much time in commercial shops, so probably missed them. At the time, around 25yrs ago, it was quite unusual. The other local machine shop was still flipping belts to get the lathes turning (S. Portugal)

ours aren't used for skimming, they take a much deeper cut, they are used for the pad gap spacing on hgv brake caliper bridges. im not sure what the lowest setting is on them, but I think its over 3mm so wouldn't be good for skimming really

 

[Sidewinder]

Just figured out where you work broken, I reckon, been there a few times, for work, not recently mind!
The lowest setting will be a thou or two, but, that is irrelevant really.

 

[awemawson]

Here you are this is what you need:

http://www.ebay.co.uk/itm/Janita-Su..._Metalworking_Supplies_ET&hash=item2593937ef0

 

[normspanners]

Drop it off at EJ Hammond Connors Quay

+1
Eric does my engine machining known him for years, In fact I do bits n pieces to help Eric out from time to time, top man.

 

[robwizard]

Wow loads of response! That thing above looks amazing! I might check out EJ Hammond then.. I really am broke though that's why I thought about DIYing it. It's cast iron so no ally to clog the grinder up haha. I will check that place out thought for sure!

Cheers

 

[Bill Edwards]

Don't use the surface grinder.
I'm sure you're thinking it could be perfect, but there is such a thing as too smooth. You do need a certain amount of roughness to 'bite' into the gasket, so unless you've the right grade grinding wheel you're onto a loser.