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Milling engine heads on a bench top mill?

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scattermaster

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#1
Good morning!
Question,
I have a benchtop mill from LMS. (a model 5500).
The specs say it has an X axis travel of 19.7".
I am working on a Ford 3.0 V6 engine and have the heads pulled off. The head gasket surface is only about 14" long.
It appears that I can theoretically mill the heads on this machine, but I'm wondering if there would be issues with the table tilting one way or the other when that much travel is being used?
I'm concerned that I might actually be milling an arc into my heads.
Has anyone done a job like this on a bench mill this size?
Opinions?
thx,
Jim
 

BROCKWOOD

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#2
Opinion: try on scrap with weight stacked under your scap test piece. Then you know what to expect without creating scrap heads.
 

markba633csi

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#3
Doubtful, there may be a loss of accuracy(and rigidity) at the extremes. My personal rule of thumb for ci heads: machine table length should be about twice the milled distance. So 14" x 2 = 28". A Bridgeport with the smallest table (32") would be required, minimum.
Mark
 
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Bob Korves

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#4
I like to do every possible thing I can myself. It is a control thing and a perfectionist thing, usually with a smug and happy ending. Sometimes I go too far, and end up wishing I hadn't even started the project. Cylinder heads and flywheels fit into that category, unless you have the industrial specialty tools and skills to do the job right -- in my opinion. Getting a cylinder head surfaced by pros is not that expensive, but buying another head and getting it in shape for use can be plenty expensive. I would not try it myself, YMMV. I don't like it when I fail at what I attempt, even more so when it ends up costing me a lot more after wasting my time and effort...

"A man's got to know his limitations." -Dirty Harry
 

JimDawson

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#5
I have machines that would machine that head, but I take my head work down the road a 1/4 mile and have the automotive machine shop do it. Just the setup time on a mill takes longer than running it down the road. :)
 

CarlosA

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#7
According to LMS, the X axis travel of the 5500 is 15.6" That is not enough to start and finish off the work unless you use a 3/4" end mill.
https://littlemachineshop.com/products/product_view.php?ProductID=5500
That is what I was going to say^

Having done this for a vw rabbit head on a clausing mill, the results were great ... but setting up to ensure the fly cutter would finish off the part was the most important thing. You`d be better off doing it on a surface plate on abrasive paper really.
 

Aukai

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#8
Then there are head gasket types that require a specific finish to seal well.
 

derf

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#9
Most engine shops grind cast iron heads on a Blanchard grinder.
 

john.k

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#10
Ive done old type iron engine heads that had soft copper asbestos gaskets.......but I would not face a modern ally head that goes with the hard steel shim gaskets,unless I could be sure of the accuracy required...........In fact Ive found heads recoed by cylinder head exchange shops are often no good due to out of spec machining.........and leak coolant on fitting.
 

P. Waller

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#11
I have machines that would machine that head, but I take my head work down the road a 1/4 mile and have the automotive machine shop do it. Just the setup time on a mill takes longer than running it down the road. :)
What he said.
 

tq60

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#12
Ive done old type iron engine heads that had soft copper asbestos gaskets.......but I would not face a modern ally head that goes with the hard steel shim gaskets,unless I could be sure of the accuracy required...........In fact Ive found heads recoed by cylinder head exchange shops are often no good due to out of spec machining.........and leak coolant on fitting.
A friend has had this happen.

If you have a straight edge then visit an automotive shop and after you get quote ask to check their work meaning place your straight edge across some finished work.

Our friend had a performance engine that ate head gaskets.

Their high dollar machine was out of alignment and trashed block and heads.

Check the shops work first.

If they have grinder it is Likely okay but poor maintenance or age poor operator could allow poor outcome


Sent from my SAMSUNG-SM-G930A using Tapatalk
 

scattermaster

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#13
Hmmmm!
In my mind I had ordered the Delux version and it's listed at 19.7" X travel BUT, I just looked and sadly I was mistaken...
I guess it's a moot point anyway. It sounds like the consensus is that I should leave that to the experts.
Guess I'll just have to find something else to whittle away at.
thx guys.
 

cjtoombs

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#14
I worked at an automotive machine shop back in the 80's and early 90's. Unless the head is marked by the head gasket (indented) or had more than .004 warp, we didn't recomend surfacing it. You could get by with more warp on a long 6 cylinder head. The head bolts will easily pull that out of the head. If you are looking to reduce chamber volume to raise compression, we generaly recomended staying under about .020 off the heads, as you can start having intake fitment problems (unless you modify it, as well). Some shops use a grinder, some use a sanding bed, some use a big fly cutter usualy refered to as a rotary broach. We used a Van Norman 562 surface grinder that gave a superb finnish, some of the ones that use cutters don't leave a very good finnish, depending on how the cutters are set up. The thing about automotive machine shops is that the machines are highly specialized which makes setup much easier than you can do on a comparable general purpose machine. This makes the cost for work relatively low, since setup time is minimized. I have a well equiped shop and still take most of my work of that type to the automotive machine shop in town in order to save my shop time for stuff I can't get done elsewhere, and because it is relatively cheap.
 
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