Machinist question

I'm doing the traditional and necessary cleanup on the Wonderbus's new heads: opening the air channels, filing out the casting flash between the fins, etc. The surface for the valve cover gasket came with a few scratches and I want to make it flatter and scratch-free. My initial attempt is to use a mill-cut file, held flat against the surface and pushed away from me. While this works okay, little balls of head material seem to suddenly accumulate between the file and the head during a "push", leaving new lengthwise scratches.

What's going on, and is there something that can be done to keep it from happening?

Reply to
Mike Rocket J. Squirrel Elliot
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.....drop the file and back away. Don't try anything funny mister. Get a nice flat piece of glass and a couple sheets of wet/dry sandpaper. If ya hadn't started with the file I'd say grab 400 grit and some sovent to lubricate it and once smooth finish with 600 grit. You can still trey the 400,but will likely have to start with 320 or even 280 to take the file marks off before working your way finer. Files are for roughing in...removing material. As the piece of metal gets nearer the goal it must be smoothed with finer abrasives.. In ancient times sand and oil would be used with finer and finer sands being utilized...through the wonders of technology we have advanced to the point of gluing our sand to paper ;-) This is the same when dealing with any metal from your heads to a guitar fret. After the file comes successively finer abrisives until the finish you desire is obtained.

...Gareth

Reply to
Gary Tateosian

After I posted this question I realized that it really isn't a machinist question, since no machines are being discussed. More of a metalworker's question. But anyway . . .

Gary Tateosian wrote:

Thanks for the tip.

There were a couple of rather grievous scratches on the gasket surface when the heads arrived, so my intention was to do a little metal removing, as evenly as possible, to bring the surface down level with the scratches, with this mill-cut file, then finish up with finer abrasives. However, I am somewhat buffaloed by the little metal balls that are appearing under the file. My inner Mr. Scientist is curious to know what is happening, and if there is a commonly known way to prevent this . . . or if this kind of alloy will pretty much do this whenever it is introduced to a file.

Reply to
Mike Rocket J. Squirrel Elliot

Use a hack saw blade, or chuck a rat-tail file in your drill, or both

John Aircooled.Net Inc.

Reply to
John Connolly

To smooth the valve cover gasket sealing surface? You're pulling my leg, right?

Reply to
Mike Rocket J. Squirrel Elliot

Reply to
Wolfgang

I thought you were asking how to remove the casting flash between the fins

john Aircooled.Net > > Use a hack saw blade, or chuck a rat-tail file in your drill, or both > >

Reply to
John Connolly

All the way to Taiwan, where you could pinch a set of cheap valve-cover gaskets between your toes.

You are not supposed to touch that sealing surface with ANYTHING.

Jan

Reply to
Jan Andersson

I wrote, "The surface for the (new) valve cover gasket came with a few scratches and I want to make it flatter and scratch-free. My initial attempt is to use a mill-cut file, held flat against the surface and pushed away from me. While this works okay, little balls of head material seem to suddenly accumulate between the file and the head during a "push", leaving new lengthwise scratches."

The scratches I found on the new heads are sufficient to allow oil to leak. Surely we are allowed to touch that surface with /something/ to get rid of scratches?

Reply to
Mike Rocket J. Squirrel Elliot

A home mechanic does not have such tooling. Best you could do is use soft gaskets and thick vaseline.

Or you could try whatever means you find adequate for the job, and risk it. It might work. But if you ended up with a nice, smooth mirror finish surface, how can you be sure it's still *straight*? The soft gaskets can take up some imperfections, but they don't perform miracles. Just be careful and don't overdo it.

Jan

Reply to
Jan

On Mon, 14 Jun 2004 22:36:46 -0700, "Mike Rocket J. Squirrel Elliott" ran around screaming and yelling:

unless they go from the inner surface to the outer you are better off to leave them alone....if they make a "drain" from inside to outside you would be better off to build it up instead of taking material off...remember your valve covers are held on with tension springs(bails) and when you remove material from the face you lose tension...which could make oil leaks.... JT

Reply to
Joey Tribiani

One of the "shadetree" ways to machine an aluminum surface flat is to find a true flat surface, such as the top of a table saw or a sheet of glass, metal stock, whatever. Use duct tape to tape down the ends of wet n' dry 400 grit with the business surface up of course. Shoot it with WD40 to get it good and wet. Slide your piece back and forth, rotating it 90 degree's every X strokes. Take care to hold the piece in such a way to create even pressure over the surface as you work it. Hit the paper with more WD40 every now and then to float the swarf away. Once you've started, check the surface every minute or so to see how your coming. About 10 - 20 minutes depending how deep the scratches are.

I don't have a head in front of me but I'd imagine you would have to pull the rocker studs. And are the bosses for the stands lower or even to the v/c surface? Usually new heads always have some signs of handling on the sealing surface but it still seals up OK.

RT

Reply to
Raymond Lowe

The sandpaper (wet or dry) is your best bet. A good flat surface for this would be your new Granite Counter Top in your kitchen. However it is suggested that you wait till your wife is not at home.

Good luck, Butch

Reply to
Anton382

Reply to
ilambert

Thanks, everyone!

Reply to
Mike Rocket J. Squirrel Elliot

I do the same thing, with the same results. I think the problem is just that the alum is just too soft. I end up taking one stroke at a time and rubbing the file clean after each stroke. I'm sure there is a better solution. Probably one of these would be, but I haven't tried any of them yet.

Buy an Aluminum cut file. They should handle the soft metal better. A good file is a fine tool, but it takes skill to know how to use one. Lesson one is to let up your pressure on the return stroke.

Spray WD-40 on the file. I know it works on rotary burrs, so it might help here, too.

Whenever I do this I'm just in the mode of "I just need to do this one set of heads." So I don't mind that it takes me 20 minutes instead of

  1. John was talking about how to remove the casting flash. Sounds like he missed your main question.

-

----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Reply to
Jim Adney

I see everyone has pretty much hashed this one out, however, I haven't seen one mention of "draw filing" which will help you achieve the results you are looking for. and with a minimal amount of fuss.

If you are doing what it sounds like, you're not far off.

The process goes something like this:

Grasp file firmly with both hands, such as you would handlebars of a cycle. piece located longitudinally in front of you, with medium to light pressure, pull evenly with both hands to and fro. ( toward your navel and away ) accross the surface to be smoothed. This should result in the "mirror finish" that someone mentioned in an earlier post.

Once again, this method and use of a file is called " Draw Filing "

hope this helps.

( this method also everything but eliminates the Filings from causing further scratches, but should be watched as working. I call this a poor mans machining tool.)

Remove "YOURPANTIES" to reply MUADIB®

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Reply to
MUADIB®

This is the solution I settled on today. Yet one of the four sides of the sealing surface consistently pilled, no matter how careful I was. I figure this aluminum is just really soft, and especially so on that surface.

I achieved a fairly good surface, but not as nice as I would like. I bet it's plenty flat to seal well, given the compliance of the neoprene-cork gaskets I use. But it's kind of a matter of wanting to know how to do better. I've heard tell that aviation supply house sell coarser-pitch files, called "vixen" files, and I'm going to track one of those down.

the problem of how to deal with the protruding rocker shaft mounting bolts notwithstanding, I have hesitated to get involved with any of the sandpaper-type abrasive solutions suggested. I am not convinced that I would be able to remove all the abrasive (e.g., the aluminum oxide or whatever is on that 600 grit wet/dry paper). Aluminum is so soft that some of the grit will remain embedded in the head, then later float out with the oil and into bearings.

My fav-o-rite supplier, McMaster, sells aluminum files with a coarser pitch, designed not to clog, which may or may not be the cause of pilling. I'll try.

Thanks for that suggestion. I understand that kerosene is pretty much the same and I have a gallon of that.

Yeah, I tend to write conversationally and folks scanning the messages can easily miss my question buried in my jabber.

Reply to
Mike Rocket J. Squirrel Elliot

Hey -- I'll give this a try!

Reply to
Mike Rocket J. Squirrel Elliot

Whenever I draw file I make sure I #1 have a very good file. #2 I take some regular chalk, like used in schools, and scrape onto the file, filling every little groove. #3 use a file card every few strokes to clean the file. Repeat # 2 and #3 as often as necessary. The chalk acts like what you are trying to do with WD-40 and kerosene. I just prefer to work in a dry environment. Besides chalk was used long before WD-40 and possibly before kerosene! :-)

Reply to
kywoodwrkr

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