I know “where’s the piston vice” “you should be using a piston vice”
theres more than one way to cut pockets and this is the “without a piston vice method”

Intakes were hitting radially ok depth wise
Adjusted flycutter to proper diameter on scrap piece aluminum
squared piston to table in x travel along t slots using a parallel against t slot and up against piston along pin boss
tilted head using a valve in drill chuck to get angle same as existing pocket
centered y up on existing pocket
touched off on pockets existing od edge
moved over .079”
plunged down till cut blended in with floor of existing pocket
came out pretty good for no piston vice

mocked up engine and clears now
can see it perfectly down the intake port (kinda hard to see in pic but if you look kinda mid to top left you can see it drop into pocket

Tried to get a video of how close the valves are together on overlap(noticed some people didn’t understand valve to valve clearance! Look real close and you can see it, where intake and ex look like they are gonna clip each other
havent had to worry bout this kinda of valve to valve since the days of building z1/kz1000 engines



Test cuts in scrap to check cutter setting

Tilted mill head

Valve face touching floor of pocket to check angle and y position

 

Video clip 1–cutting pocket
video clip 2- mocked up valve dropping into pocket (moving valve/rocker by hand (checking p-v)
video clip 3–valve to valve very close

 

Works for me,

 

Invest in the right tooling & fixtures.there are pistons vises for a reason,plus you NEVER want to have to tilt the head of the mill for any machining proceger.all our fixtures are set to the angle they need to be at & yes, we use a piston vise whenever doing pistons.all of our mills (3) stay perfectly trammed at all times (I've got a friend who has a piston vise for sale if your interested)

 

Piston vices are nice but if you don’t have one then this is an acceptable way to make the cut.
also don’t agree with you saying NEVER tilt the head of your mill.
explain why would the mill head and turret be made so adjustable if not for cutting odd angles or odd workholding solutions? It’s not just the tiny bit needed to tram the head in to the table. That would require little more than the “slop in the holes” approach not building it with degree scales and able to tilt and nod roughly 45 degrees and have a turret that spins 360. That statement doesn’t make sense beyond if your saying never tilt the head cause it’s too much trouble to tram it back in to the vice or table or because someone behind you might not know how to do it or whatever. Whenever I take the mill head out of tram I set it back when done. It takes a whole 5-10 minutes once you know what your doing so I don’t see the big deal in tilting the head. It’s like taking off the vice, no one like taking it off of it can be avoided cause we know we got to realign it to the x-table travel. I can have the indical with a dti premounted and have the vice set in a few minutes, no big deal.

now with that being said, sure a piston vice is the way to go and would make it a much easier job. But it’s not the only way to skin a cat and I don’t mean that to refer to the extremes of hand clearancing a piston with a burr in a die grinder.

ideally I’d have a whole shop full of mills all set up with dedicated tooling like Dragon Man Mel has in his shop but since that’s beyond my means right now I work with what I have and in this case get the same results.

how much for that vise?

 

well,just like pretty much everything,theres a right way & a wrong way to do things,we do stuff the right way here,the reason you want fixtures to hold the work at the proper angle is to assure repeatability of machining to be the same of different parts getting the same proceger,its a free country & you can do stuff anyway you choose,but i really wouldnt be "advertising" jerry rig machining methods,your not going to impress very many people.she wants 650.00 for the vise (her husband passed and she`s selling his shop & equipment) BTW that dragon guy is a joke when it comes to machining anything,messed up more peoples parts than all the shops in the country put together.

 

Not trying to impress anyone, really just showing that it isn’t rocket science building these engines and some relatively simple tools/machines can go a long way. These engines are a pretty simple two valve pushrod design after all. The method I showed is far from jerry rigging. Jerry rigging is taking a die grinder with a burr to your pistons. Hardly is jerry rigging using a Bridgeport with two axis controller. The forums here to share knowledge and I was just showing this is a method anyone with a mill can use to modify an existing valve pocket. There’s a lot of people nowadays that may have or have access to a milling machine yet not have specialized fixtures or in this case a piston vise. If these pistons were blanks with no pockets to go off then that would be different. I might need a vise to be able to set an arbitrary angle not just go off an existing angle and open up a pocket for clearance. Yet in that case I still wouldn’t need a piston vice nessecarily because as a general machinist I know how to pick up any angle with a dial test test indicator. Simply clamp the head on the table with a valve in the head with no spring and “pick up” the valve angle with the dti.

having worked in manufacturing/machine shops that aren’t specialized in engine building I learned how to make do with what we had on had for any given job. I understand what your saying regarding repeatability and certainly time saving if your machining engine parts/building engines for a living. Yet, since that’s not what I’m doing here, modifying 2 pistons doesnt warrant the expense of brand new piston vise at this time.

thanks for the input regardless

and btw, I merely commented on how dragon man shop is full of dedicated mills with dedicated fixtures. I in no way endorsed his work as all I know of him are in the shop tour videos he posted on you tube. No one could argue that he doesn’t have an impressive setup of manual machines. He has at least 15 bridgeports/clones pre set with fixtures for guide bores, twin plugging, etc etc. multiple sunnen honing machines. Kwik way boring bar, seat and guide machine, nice leblond lathes, engine test run stand, and many many more machines I don’t recall at this time. Any manual machinist that doesn’t carry an oversized ego would be impressed with his shop. Yet having never seen his work or finished products I can’t speak for his quality of work in either direction! I know I’d loved to have his setup!!!