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An "easy" way to shuffle pin?

I'm getting ready to seal the bottom end up and as I was looking the case over I wondered if it would be possible to shuffle pin by clamping the cases together with #8 bearing installed and then drilling down from the top of the webs on the 1-3 side into the webs on the 4-6 side and install 3/16 x 1/2" dowel pins on the 4-6 case side? It would be dead nuts on, no jigs or transfer punches involved. The only problem would be on webs 2,4,6 the hole would intersect the squirter hole and would have to be plugged to prevent oil pressure loss with say a threaded or press in plug. The squirters would probably have to be removed for drilling but no big deal. In fact the tops of all the holes could be tapped so that the cases could be separated easily by inserting an appropriately sized rod into the hole and then threading in a bolt to press the cases apart. Would the hole weaken the web enough to be a concern? It would be a piece of cake to do on a mill, not something you'd want to do by hand. It seems too simple, what am I missing? The squirter drilling is the slanted line.

Old 06-11-2016, 02:34 PM
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I install alignment barrels on each web like #8 with that has to be done with it clamped up too, its easy after about the 5th one you do and all the special reams, jigs etc you have to make.

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Old 06-11-2016, 05:46 PM
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I've seen that, I like that method, it should be accurate.
Old 06-11-2016, 06:57 PM
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I measured the cross sectional area of the webs (width of web x height) where the holes would be drilled and a 3/16 hole would result in loss of 27% of the area.The thru bolt holes remove a large portion of the web of course but they are located further back from the crank axis. The mill head would be trammed to the cylinder base mounting surface on the spigot to make sure the hole is 90 deg to the web. I'm not planning on this for this engine, maybe on the next big power build. Would like to hear any comments from the guys who do this.
Old 06-12-2016, 06:27 AM
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Only one comment? I don't see why this won't work.
Old 06-16-2016, 09:15 PM
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I'm a fan of the method Craig uses, with bushings - That's how Porsche does it for the #1

For indexing, you drill/bore down the throughbolt holes from one side of a clamped case, and the right distance into the other case half. Then you insert the bushings into that side (being careful with depth or notching to avoid problems with oiling passageways where appropriate.

Finish up by making and inserting hollow plugs to the the top of the throughbolt hole back to size. Works great, and perfect indexing along with no weakening of anything.

Try it - you'll like it.

I will say that the one case I had shuffle pinned didn't have indexing problems - went together and came apart with about the same effort as with the bushing method. But the machinist who put me onto this said the issue with shuffle pinning in the usual way is with getting the indexing exact. Maybe with CAM equipment this is not the issue it was with transfer punches?
Old 06-18-2016, 04:01 PM
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Quote:
Originally Posted by Walt Fricke View Post
I will say that the one case I had shuffle pinned didn't have indexing problems - went together and came apart with about the same effort as with the bushing method. But the machinist who put me onto this said the issue with shuffle pinning in the usual way is with getting the indexing exact. Maybe with CAM equipment this is not the issue it was with transfer punches?
I really don't believe that the 'transfer punch' method has any merit.

If you just think about the fit needed to line up so many dowels that the case will slip together it is just impossible.

The only way this works is to use 'slip' fits on the dowels on one side of the case which assumes a relatively large clearance. Even then cases treated in such a manner commonly need to line bored to prevent the crank from binding and the bearing cost becomes quite high.

The radial clearance of a slip fit dowel is also sufficient to allow enough movement for fretting to take place and I believe this defeats the objective.

Looking at trying to drill the holes 'blind' you have to look at the positional accuracy of a modern 5 axis machine.

The problem will always be concerned with trying to locate the first hole that needs to be drilled which will be a real trick.

I think it could be done with a Jig Boring machine in a temperature controlled environment if you wanted to avoid line boring.

Any method that clamps the case and then lines up the holes by drilling from outside must give a better result.

However, the main problem is still concerned with the fit and the clearance around the dowels.

Adhesive wear (fretting) only needs between 5-40 microns of relative movement so any clearance is the enemy.
Old 06-19-2016, 12:44 AM
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With my method you can set the dowel pin fit to be a press fit on both sides. The top 1" of each of the holes is counterbored and tapped. To split the cases an appropriately sized rod is dropped into each of the holes and then a fastener is threaded into each of the holes to force the rod against the dowel and force the cases apart. So you have exact alignment of all the holes, the tight fit req'd to stop fretting and an easy way to separate the cases.
Old 06-19-2016, 06:59 AM
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Could you go down like boosted suggested but instead with just a pilot bit, then take both case halves and follow the pilot holes from the inside of the cases?

This would remove less material from the webs and then just plug the outside hole where the pilot entered.

How does Ollies or Competition Engineering do it? I've never seen a complaint that they mucked this operation.

andy
Old 06-19-2016, 07:50 PM
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I don't see how you can follow the hole any cutter on a vertical mill will just cut a new hole and unless you can centre them with sufficient precision and then index the job correctly then alignment will always be an issue.

If you want to carry out this job without line boring then you either need clearance around one set of dowels or you need to clamp the cases.

If you have enough clearance the cases fit together and all looks good but the 'pins' don't prevent a small amount of relative movement.

Unless you press the cases together then there must be clearance.

An m6 fit on a dowel which is what would be recommended by the relevant ISO Standard needs an insertion force of 15kg.

The same ISO Standard recommends a 0.003" diamteral clearance for a 'slip' fit which is a radial clearance of 0.0015" or 60 microns. This is more than enough relative movement to allow fretting of the case mating surfaces.

When you 'pin' a case that can easily be assembled/disassembled there will be clearance around one set of holes which is why I question the entire process.

It looks good, it sounds good but I don't think it has much effect.

I come back to the two questions I always ask about shuffle pins.

What creates the forces that cause shuffling ?

What is the precision to which the pins are aligned?
Old 06-19-2016, 11:42 PM
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You make a tooling plate out of Aluminium index on the front beating with a half round and the back two dowls on the thrust bearing and fit two dowls on other side when you flip it over on the other half case all holes are indexed on the plate and fit with drill bushings to help you line up the drill and it is drill on a mill after the head and table have been checked for alignment.
This is how most people do it including Ollie's.

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Old 06-20-2016, 12:12 PM
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I understand why this looks and sounds OK but it still doesn't define the accuracy and the fit.

The point I am trying to make is that if the dowel on one side is a loose fit then movement can still occur. If they are loose fits on both sides then surely there isn't much point.

If the dowels are a tight fit than case assembly/disassembly becomes a problem.

Drilling holes accurately is just a real PITA.

Machinist Drilling Mechanical Tolerance Capabilites Chart - ANSI Size Drilled Hole Tolerance, ISO Metric Drill Sizes - Engineers Edge
Old 06-20-2016, 02:46 PM
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I understand as well and really I am not a fan of this process it does require some pressure to assemble the cases and it the pin fit is .001 or more it defeats the purpose. Porsche themselves just change the through bolts on every build and torque the daylights out of them on installation and it seems to work.

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Old 06-20-2016, 03:03 PM
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