Fixturing Cylinder Heads On a Mill
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    Default Fixturing Cylinder Heads On a Mill

    I'm looking for ideas on how to fixture a set of cylinder heads for some machine work, including some chamber modifications and "decking" (milling the head to engine block interface flat) after some welding and other modifications. They are roughly 19x7x6" and about 25#, and I have an 8" insert style sandvik mill that I should be able to cut the decks in one pass with. I know that there are fixtures designed specifically for this kind of thing, but I do not plan on doing this enough to make it worth the money to buy or build one.

    The big issue is that the deck surface of the head is not at a regular angle to any of the other surfaces (and I may want to be able to cut at 2 different angles) and I'm just not sure how to hold the head at the correct angle firmly enough that it won't move. I do have 2 of this style swivel angle plate:
    http://www.shars.com/files/products/...2-2310Main.jpg

    and one thing i"m considering is trying to bolt the head to one of those on each end but I haven't quite decided if there is a good way to bolt the head down (the through holes in it go through the surface that I want to machine so using them will get in the way) or a good way to get it indexed correctly/right angle/right height relative to the table without a lot of fussing/shimming. There are a few threaded bolt holes on sides of the heads that are not the ones getting machined, but I'm not sure how to use them to bolt the head down since I do not have enough room to bolt something to them and then use a traditional hold down setup (the head is about the width of the angle plates, the surface of the plates will not stick out past the sides of the heads)

    Anyone have suggestions, hints or other ideas?

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    I started to get into the cylinder head work a while back, and since I'm a cheap bastard...I made this rollover fixture.



    Angle plates from Enco, some blocks of scrapbinium, an old 327 crankshaft, and some bolts.

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    Its surprising how many people have similar ideas.
    This isnt my setup, but one I plan to copy at some point in the near future but with pivots between the clamp surface and angleplate ends as this was just a fixed rigid jig the guy made up to do his porting with. The poster above's used crank webs to form this seems like a great idea.


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    I had to do exactly the same thing just about a month ago on a head (Wisconsin VE4 but the same issues) There were bosses with bolt holes on the top of the head but none of them were the same height. Also this is an air cooled head so the fins were not something I could reference off of. I ended up putting nuts on 3/8" bolts about two inches long and putting the heads of the bolts on the table. I reached under it and used two wrenches to loosen and tighten the nuts which jacked up the head until it read flat with an indicator. Sort of like using half a dozen jack screws. Then I bolted it down LIGHTLY to the table through the spark plug holes. I was able to fly-cut the head taking off a total of .020" to finally get it flat (this was after tig welding up a bugger where the gasket blew and channeled the head. Worked great. I thought it was pretty flaky at first but it held up fine.

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    I have a fixture like the one that lbhsbz has in his post, I made it in about 1982, still works great. I also have angle blocks that bolt to small block Chev heads, a pair for valve guides/spring pockets, another pair for the gasket rail, and another pair for valve seats etc.

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    I assume that we are talking about Aluminium heads? If you are thinking about cast iron heads then I think you need angle blocks that are much heavier than the ones that you are considering. Also an 8" face mill on a cast iron head will need a big heavy mill with some serious horsepower. I don't think that a face mill that big is a sensible match for a Bridgeport for example, even if you had a way to mount one on an R8 holder.

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    -here's my methods of holding heads--each link has some pictures and some related story about it all.

    Bill Jones Page 1

    Bill Jones Page 12

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    Bill- I see you have the dreaded salt disease also.
    Dan
    #221 V4FL

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    Quote Originally Posted by bill jones View Post
    -here's my methods of holding heads--each link has some pictures and some related story about it all.

    Bill Jones Page 1

    Bill Jones Page 12
    Thanks for sharing your site Bill. I love all the homemade stuff. I especially liked the videos of carbs during dyno pulls. Those float bowls really churn!

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    I belive the Yellow Bullet website just had a topic on head holding fixtures.

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    Would you link that thread here?

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    If you are going to do this only once, or once in a blue moon, take the head to Fairfax Auto or another local machine shop and have it done. They will do it right and in a timely fashion.

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    Quote Originally Posted by billmac View Post
    I assume that we are talking about Aluminium heads? If you are thinking about cast iron heads then I think you need angle blocks that are much heavier than the ones that you are considering. Also an 8" face mill on a cast iron head will need a big heavy mill with some serious horsepower. I don't think that a face mill that big is a sensible match for a Bridgeport for example, even if you had a way to mount one on an R8 holder.
    I don't know, I do it all the time, I've used it on pieces with similar cross sections like supercharger cases and a few cylinder heads that could be clamped down flat. I kind of get the impression that the people that have problems with it are those using the variable speed heads, where the standard drive J heads, even with the smaller motor seem to do fine. Mine has a panhead motor on it and VFD and when it doubt I pulley it down and up the frequency to get more torque out of the assembly. Sure, not as optimal as doing it on a larger mill but it does work.

    Quote Originally Posted by bill jones View Post
    -here's my methods of holding heads--each link has some pictures and some related story about it all.

    Bill Jones Page 1

    Bill Jones Page 12
    Thanks Bill, those are pretty much the standard when people are asking this question, do any search for it online or on most forums and you'll find links to your site. I'm curious, were the 2 Kurt vices really close or did you have to adjust for their differences? I noticed that you do have them labled L and R in the pictures, I'm wondering if that's because of any differences between them and your setup compensating for them or?

    Quote Originally Posted by Gthphtm View Post
    I belive the Yellow Bullet website just had a topic on head holding fixtures.
    I'll second, can you post a link? I've seen a few discussions about it there but not sure that one really covers it well

    Quote Originally Posted by AHS View Post
    If you are going to do this only once, or once in a blue moon, take the head to Fairfax Auto or another local machine shop and have it done. They will do it right and in a timely fashion.
    Well, I want to experiment with changing chamber profiles, have modified, welded and need to cut coolant passages and need to cut a different bolt pattern in the intake face. All custom stuff that will scare away most shops.

    Even if that wasn't the case I've seen a few responses "just take it to a automotive machine shop setup for this and they'll do it for $$50." Well I've tried a few of the local shops (I"m in between DC and Baltimore) and keep getting prices in the $150 range, which I think is a bit crazy, and I'm betting that when the see the plugs welded in the deck surface I'll get a "you didn't say anything about that, we'll have to do extra work with them..."

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    Right now I'm thinking that I'm going to try a couple of angle plates bolted to the accessory bolt holes in the end of the heads and some screw jacks and clamps along the length to support it and see what I get. I wish I had a junk aluminum head to test it on, I have a few cast iron that I can experiment on, but the ones that I need to do the actual work on right now are aluminum and the fact is that no matter what I do the cutter will act different.

    I have 2 Sandivk Mills in that size range that I really like, that I usually run for this kind of thing with half the inserts installed and get a really nice cut. OTOH, there's a few people that seem to really like this thing:
    eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

    and I do have a couple of 1x8" aluminum rounds sitting around that I could easily make one out of, I could make it to use 3/8-1/2 lathe tooling (I have some brazed ones, and even a few extra insert holder style ones), but I don't really know what the angle should be for the holder or if the angle should be different for the 2 different styles even though they are ment to be interchangeable on a lathe (I'd love suggestions if someone has them).

    People seem to really like the HQT setup for doing this with a for very heavy and clean cuts up to .125" on a bridgeport:
    8" ALUMINUM SHELL MILL
    and they seem to imply that how well it works is because of it's _light_ weight (that doesn't seem to make sense to me) and something about cutter angles only allowing each cutter to take a .06" cut at a time which I didn't understand
    Last edited by Silverback; 04-06-2012 at 02:35 PM.

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    Quote Originally Posted by Silverback View Post
    I'm looking for ideas on how to fixture a set of cylinder heads for some machine work, including some chamber modifications and "decking" (milling the head to engine block interface flat) after some welding and other modifications. They are roughly 19x7x6" and about 25#, and I have an 8" insert style sandvik mill that I should be able to cut the decks in one pass with. I know that there are fixtures designed specifically for this kind of thing, but I do not plan on doing this enough to make it worth the money to buy or build one.



    The big issue is that the deck surface of the head is not at a regular angle to any of the other surfaces (and I may want to be able to cut at 2 different angles) and I'm just not sure how to hold the head at the correct angle firmly enough that it won't move. I do have 2 of this style swivel angle plate:
    http://www.shars.com/files/products/...2-2310Main.jpg

    and one thing i"m considering is trying to bolt the head to one of those on each end but I haven't quite decided if there is a good way to bolt the head down (the through holes in it go through the surface that I want to machine so using them will get in the way) or a good way to get it indexed correctly/right angle/right height relative to the table without a lot of fussing/shimming. There are a few threaded bolt holes on sides of the heads that are not the ones getting machined, but I'm not sure how to use them to bolt the head down since I do not have enough room to bolt something to them and then use a traditional hold down setup (the head is about the width of the angle plates, the surface of the plates will not stick out past the sides of the heads)

    Anyone have suggestions, hints or other ideas?
    How about sharing what type and brand of head you are using ?? SBC, BBC, Hemi ????

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    Quote Originally Posted by Mark Leigh View Post
    How about sharing what type and brand of head you are using ?? SBC, BBC, Hemi ????
    The current project is an SB2 LT1 head with the coolant passages welded and modified to work on a traditional SBC, intake modified to work with a prea '87 bolt pattern and port location, but I've done work on chevy, ford, pontiac, nissan, assorted bike and even briggs heads.

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    Here is a commercial example of a fixture that probably will do the angles that you want. If you have the angle plates, you could make something similar w/o too much trouble I would think.

    http://www.bhjproducts.com/ bhj_content/products/cylinderhdtooling/chf.php

    Not sure why it keeps changing the url, hope this works, take the space out.

    Alex

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    Here's another fixture - Cylinder Head Fixture

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    Silverback:

    -my vises came from Enco---quite likely made in a foreign country---seems like I paid about $89 each for'm.

    -For sure I have removed the stationary hard jaws and machined those two mounting surfaces to get'm dead nuts parallel to each other.

    -I double checked the bar today----it sits absolutely level when tightened up in both vises---and it's also square along the length if i remember to push on both vises when I sung the t-bolts down.

    -My habits have lead to marking things with color---red for left/green for right----red for #1/white for #2/blue for #3 etc---and I tend to give marriage vows to certain components like that to eliminate chances for errors later on.
    ------------------------------------------------------------------------
    -I have a short chain attached with a .020" and a .025" feeler gauges as a simple way to raise the right side of the bar up which moves the right side bolt holes up slightly----I use the eccentric height adjustment bolt on the left side--this eccentric bolt has a limited range of maybe .016" up and .016" down--so sometimes I need the right side up slightly to be able to get the eccentric in the proper range I need to bring the heads left side up to level with the right side.
    -------------------------------------------------------------------------------------------------------------------
    Dan:

    -Yeah---I started going to Bonneville in the mid 1980's---got involved with Jim Zupan and his two roadsters, helped Roger Griffith with his '71 Camaro---helped Kenny Kloth with his 49 Merc flathead and also have helped Jesse Winders with his VW pickup and some with his little diesel streamliner.

    -It's neat to have Bonneville basically right here in my back yard---took me too many years before I ever went out there and discovered the magic of the place.
    ------------------------------------------------------------------------------
    Forestgnome:

    -Ryan Brown came to my place and stayed a few days maybe in the late 1980's or early 1990's---I happened to be flowtesting flow rates thru some Holley float bowls and I had found that same aeration problem and showed it to him as one of the topics we discussed during his stay.

    -He already had the engine dyno and took a fairly serious interest in the bubbles and did that picture window test--then set up his camera and did the video of that and the hi-rpm nozzle pullover etc---dealing mainly with 2 barrel race engines.

    -later on Ryan got his website up and offered me some space to show some of my stuff along with his.

    -It's nice to have great friends like that.
    Last edited by bill jones; 04-07-2012 at 04:51 PM.


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