good tool/technique for center punching holes?

[Nickmm]

Hey all,

I have a dilema. As steady as my hand is, I am working on a project which requires me to make 16 near perfectly spaced holes in a piece, all while lining up two patterns to mAtch up.

Basically, I am redrilling intake manifolds to a new bolt pattern. To do this, I want to take the two intake gaskets, lay them over each other so the ports match, and drill both bolt patterns into a steel plate so I can attatch this to the manifold as a drilling pattern. The intake manifolds do not fit into my mill properly, and I haven't found and sort of 90* attatchment id need to do this.

So I'm really looking for a punch that can center on a hole of a gasket somehow. Then I can drill a pilot hole and be damn near perfectly accurate, but just a center punch and drill press is too far off so far.


Any ideas, id love to hear them.

Nick

 

[bobadame]

Wouldn't a transfer punch do what you want to do?

 

[Nickmm]

Not sure, I haven't tried one. I'm thinking no, as the gaskets don't have the depth, but you did give me an idea. I appreciate it. I think, I can get the gasket machined out of plastic off the shelf for about 50 bucks. That will have the proper depth for use of a transfer punch. I found a decent looking automatic universal transfer punch that may work. Thoughts?

 

[racingtadpole]

If you have a mill why not make a drilling jig to pilot the drill. You could make that house both sets of stud patterns.

Or make a pilot for a ***** punch that fits into the hole of the gasket.

Personally, I wouldnt use the gasket as the template, I would measure off the manifolds.

 

[Nickmm]

Ideally I want to make a drilling jig, but I'm really not sure how to go about it. I can weld and I have access to a lot of machine tools, but I'm not used to process engineering. I usually just cut steel and slap it all together.

Ideally, I would make a drilling jig that bolted to the manifold with the old bolt holes, and piloted the drill for the new holes. Not sure what it would look like however.

 

[goodysgotacuda]

Transfer punches are pretty handy

http://www.harborfreight.com/28-piece-transfer-punch-set-3577.html

 

[bad_idea]

I have no idea how to solve this one, I am curious though. I suggest you look on youtube. It sounds like you are trying to do something common enough. Someone on youtube must have figured an efficient way to tackle the issue.

 

[jdieter]

I'm sssuming your doing this for an automobile engine. I wouldn't use the gasket as a template. Cut all-thread to fit the tapped holes in the block. You can either turn the pieces to a point for a scribe or lightly center drill them. Center drilled you would use a divider to layout the holes, pointed you would mark directly on the template. With either method all the pieces must be at the same elevation relative to the block. For a template use aluminum of the appropriate thickness depending on how you want to use it, either finished size holes or over-sized to fit a hardened steel guide for the correct drill if the template will see heavy use.

 

[rsanter]

What type of engine?
I assume it's an inline not a V type but who knows

I would look to see of someone already makes the template you want if it's something that is semi commonly done.
I like to take neasurements and do a layout on a fresh piece of steel. Do your drilling and then verify against both pieces

If you showed pictures then some of the machinists could offer advice

Bob

 

[iron_worker]

Transfer screws would be pretty useful in this case:

http://www.penntoolco.com/catalog/products/products.cfm?categoryID=2258

Put transfer screws into a couple of the holes ... as many as you think you can get a good punch mark from with one firm whack... Then drill those 2 holes to size using a drill size that gives very small amount of clearance over bolts of the size required. After that you can put transfer screws in the other holes and tighten the piece to the head using bolts in the two holes you've already created. You can remove and change the position of the transfer screws so you get all the holes center punched as required.

I think I would recommend bringing the bolts down to "snug" so the piece just rests against the transfer screws and giving it a firm whack with a mallet to transfer the marks. This way you're not using the bolts to pull the piece down and possibly causing it to bend.

Once you have all the bolt holes where the should be you can start trimming the outside and creating the port shapes. Smearing some grease or paint on the head and then pressing the piece to it will help to show the port shape and such.

Hopefully that makes sense. ha

IW

 

[gahrajmahal]

Line up the gasket on the engine and if the holes are perfectly aligned use the transfer punches. This should get you +/- .010 You may get a little more runout over the 4 bolt holes but it should work OK. Be meticulous with your drilled holes. I would invest in a centering drill bit also. It has a heavy shank and will minimize deflection you would get using a standard 1/8 drill as your pilot hole.

 

[iron_worker]

Pretty hard to use a transfer punch on a gasket unless it's very thick. The nub on the transfer punch will likely hold the cylindrical body of the punch up over top of the gasket... so you may more or less just end up "eye ballin it" that way.

IW

 

[gorilla]

Make/ buy a bushing that fits in the gasket and then use a transfer punch in the bushing. If you use a bushing that's about 1" tall and you hold it down to the metal you want to transfer to it should keep the punch perpendicular.

 

[Nickmm]

Make/ buy a shhing that fits in the gasket and then use a transfer punch in the bushing. If you use a bushing that's about 1" tall and you hold it down to the metal you want to transfer to it should keep the punch perpendicular.

I bet that will work. Ytmnd.

A bit late to my own party, but I uploaded 4 photos of what I have to my photobucket. I hope this link works.
http://smg.beta.photobucket.com/user/Chance901/library/

Basically, I have a mazda miata. They don't make a good manifold for this car. It makes a lot of horsepower, but the manifold is pretty garbage from the factory, and it has butterflies as well. So, the port spacing as you can see with the miata gasket on the honda manifold, is dead nuts on. The head is being ported anyway and if anything, the honda ports are slightly bigger. So the idea is basically, line up the ports between honda and miata, and insert new bolt pattern into manifold.

Once that's done, it is all easy. Weld honda injector ports closed, use the band saw to cut excess material, test fit and plane manifold.

The red one is done but not to my liking. It has enough slop in it to where you get a ridge if you mount it wrong because it can wiggle up or down. Im trying to make over 300 this next go and I want perfection everywhere to make it with as little boost as I can. My other thought is, if there is some wiggle, I can use a bore scope to line everything up as far as the ports go inside the head.

Thanks for the help, any more terrific ideas, please let me know. So far I have gotten a lot of information, and I think I can run with it. I do have an oem manifold for the mazda, and I could cut the flange off and use that over the gasket as my template.

 

[joe49]

Why not just measure it, lay it out and drill it on a drill press?

 

[Nickmm]

Why not just measure it, lay it out and drill it on a drill press?

Can't mount/clamp it and it doesn't fit. Its like 25" tall and my mill and drill press won't drop down that much.

 

[joe49]

Can't mount/clamp it and it doesn't fit. Its like 25" tall and my mill and drill press won't drop down that much.

You said you were going to make a steel template to use as a drilling pattern in your original post. If that is the case I think laying it out is the simplest way to go.

 

[joe49]

Also I would copy the heads not a gasket when you as built.

 

[dirtmister16]

seen machinests use a piece of bushing material or pipe as a guide for center punches.

just thought, you could make your own out of some bushing stock or some other material to guide your punch.

 

[strike a poser]

Depending on how thick the OE flange is, you could, after machining the cut side flat, drill the mounting bolt holes for flathead screws and bolt that back on the head and drill your new manifold bolt pattern into the old flange and mount the Honda manifold to that essentially making it an adaptor. You would have to use two gaskets, one on each side of your plate, but you should be able to clamp them enough to seal.

 

[sabercatt]

i wouldn't be too concerned with getting these perfect, just get them as close as you can and put some holes big enough to give you some wiggle room (so to speak). Your intake can have oversized holes and work just fine. I have installed many that had enough slop in them they could be moved all over the place and still seal fine.