Vee Twin Autococker

[DocsMachine]

[/quoWhat about having a part support/tail support comes in when you need it?
Do you have a second CNC holder in there

-Well, the part itself precludes a tailstock, which requires a small hole to be drilled in the end of the part. And, the Omniturn lathe I have, doesn't have a tailstock anyway.

As for a "second CNC holder", there are machines that have a second chuck, facing the first. And can use it to grab the machined end of a piece, so that the other end can be done.

A cheap used one that fancy would probably start at $80K, and besides the expense, would be FAR too physically large and heavy to fit into my glorified 2-car garage.

No, I'll get this sorted out, as I said I'm still quite new to the actual mechanics of using CNC, and it'll just take a little time, practice and experience.

Doc.

[XEMON]

What about having a part support/tail support comes in when you need it?
Do you have a second CNC holder in there?

[DocsMachine]

Curious as to why you didn't part the pin off in the same op.

-Inexperience.

No, really. The pin gets pretty small, and if I'm not very careful, can chatter or distort if I try to cut too much. Clearly, it can be done, as everybody makes pins like this, successfully. For the moment, I opted to turn these in stages, keeping as much support as I can for it.

Once I have a better handle on speeds and feeds- I'm still very new to this whole CNC thing- yeah, the "right" way will be to turn the shank, including the detent groove, then most of the head, part off, and then have a bar feeder or bar puller (which I have but have not yet used) advance the bar the right amount, and then cut another one.Lather, rinse, repeat until the bar runs out.

Still working up to that.

Doc.

[Siress]

Curious as to why you didn't part the pin off in the same op.

[DocsMachine]

Makin' a 'Cocker bolt pin, live and in color!

(Well, part of it, anyway. )



Doc.

[Nuppydog]

Ooh yeah! I see mine in that bunch. Looking forward to it!

[Chuck E Ducky]

So cool watching it all come together.

[maggot]

Oh man, awesome update. Getting pretty close.

Thanks for posting!

[DocsMachine]

Aaaand we're back on track!

Shifting over to the next major piece of this particular puzzle, I cut down the rough-sawed chunks from a couple weeks ago, and machined them to width for the front blocks.



After a great deal of jiggery and pokery I had them thoroughly perforated, bored, counter-bored, threaded and just generally kitten-licked. (That's an extra $2 per lick, by the way.)



I'd mentioned I wanted to change the profile a bit, so I milled a curve at the top to match- but clear- the profile of the barrels.



A quick ride through the belt-sander...



And a couple minutes with a corner-rounding bit...



And miscellaneous other milling, drilling and finagling, and there's six, ready to go!



(Two of the guns are pump-only, and a third is getting a more custom front block, so actually, one's a spare.)

I needed rods for the two aforementioned pumps, and rather than fight with manually threading- again- I fell back to the old tried-and-true. A Geometric die head on the turret lathe.



That's antique technology- the lathe is older and most of your grandfathers, and the die head probably dates to the fifties, but it could easily make perfect, full-form threads in less than eight seconds. There are few high end CNC lathes that could make those threads, at that size, as fast via single-point.

So except for the two midblock rods, those are now done, too.



Now, here's something I've been meaning to whip up for years, and now that I have to do a whole fistful of bolts, it was time to make the effort.



That's a jig for precisely drilling the pin bore in a 'Cocker bolt. This particular one is for the older 1" back blocks, but it won't take much to make a second body to do the newer 2K-length bolts.

That let me drill all the bolts, and then, back in the lathe, I drilled them for the detent ball and end plug for the spring.



I also spent some time drawing up the pin dimensions and trying to write a program for the CNC lathe for it (these I hand-turned)...



But I haven't had a chance to try it out yet. They're standard pull-pins, so I figured it'd be worth the time to do up a program for them. After that, with minor tweaking, I can do some up in aluminum, delrin, stainless... maybe even titanium, for those of you with extra-deep pockets. (I actually have a little Ti stock on hand, if anyone's interested... )

And a quick teaser, for those of you who are (understandably) getting a little antsy.



And finally, one of this weekends' projects was to set up a chunk of stainless in the turret lathe, and drill, bore and ream both ends.



Over to the other lathe, the OD gets turned down, and then two bits per end parted off.



Those get turned, grooved, chamfered and generally fondled (no extra charge)...



Until they look a lot like a new-style 11/16" valve body!



What's left? Not much! The valves still need to be drilled (I'll make another fixture to help with that) the bolts still need to be drilled for the 'exhaust port', and I need to make some workable pins.

That's pretty much it! After that it's just down to the individual fitting- like the midblocks, the pump kits and other unique features.

Doc.

[DocsMachine]

And now, Part Four!

And no worries, the actual build is of course way ahead of what the videos show. I'll have a proper photo update later this evening. I just have to make a few more valves, some more bolt pins, and finish the bolts.

That doesn't mean all the guns are done, but more than half should be heading out this week. (I know I said that before, but this time I mean it! )

Doc.

[DocsMachine]

And Part Three is up!

Doc.

[DocsMachine]

PM, email and that carrier pigeon you trained to light a cigarette and blow smoke signals at me. (Unfortunately, on that last one, I never learned to read cursive. )

TL;DR version: Yes, it's all easily possible, I just need to work up a quote for ya. I'll try to get some updates out you you and and some of these other fellows in the next day or two. Once I have the hardware like the pins and valves done, I'll be double-checking with everyone to be sure I have each order right.

Doc.

[Nuppydog]

Great update! Thank you!

[SETHZILLA!]

Hey Doc, can you confirm you got an email or PM from me about my order?

[DocsMachine]

First off, my usual form-letter apology:

I... I ran out of gas. I... I had a flat tire. I didn't have enough money for cab fare. My tux didn't come back from the cleaners. An old friend came in from out of town! Someone stole my car! There was an earthquake! A terrible flood! Locusts! IT WASN'T MY FAULT, I SWEAR TO GOD!

[sobs]



Seriously, I've had a lot on my plate lately, including trying like mad to get my taxes done in time, plus a maybe-a-little-unusually-large number of walk-in jobs, from Harley fixes (our week-long riding season is coming up shortly) to fishing boat parts. (I'm hoping this means everyone is finally getting to their stuff early, and that this doesn't mean they're going to flood me with work in June, the usual 28 minutes before the season opens.)

But, I've still managed to sneak in some 'Twin work here and there.

I got the first four standard pump rods made:





Two others are getting pumped, which means longer rods, and the last two are halfblocks which will also have to be custom fitted.

This was actually a bit of a delay right here, as I wasted a great deal of time trying to get my CNC lathe to cut the threads. After way too long trying to get the program to work (hey, I'm still really new at this, okay? ) I was never able to get an acceptable thread.

It's kind of tricky- the stainless wants a minimum amount of cut, else it "rubs" and work-hardens. But, the rod is thin enough it deflects- you can actually see it bend away from the cutter slightly. This is a case where I have to have my speeds and feeds pretty much exactly right, and I think I need better threading inserts. One of these days I'm going to have to call up a Sanvik dealer or similar, and invest in a pack of some top-notch stuff.

Anyway, the "fix", at least for the moment, was to thread 'em on the manual lathe, to close to size, then I just finished with a standard die. That produced a good, clean, acceptable thread.

I was also able to get the detent holes drilled and tapped...



Got the bolt blanks turned down to size...



And the grabby-end profile cut...



And ready for finishing to length, then drilling for the pin boss and exhaust port.



Somewhere along the way, I made up a fixture and milled off the bottom of the backblocks (including the inner recess, which I apparently didn't get a photo of)...



Then made up another fixture and got the bolt-pin holes drilled.



Also along the way, I took the time to redraw the drawings for the front block, and then whipped up a quick test piece to make sure everything fit right.



I'll probably be altering the overall profile a bit on the 'production' pieces- again, test part- but yeah, all the dimensions were spot-on.

I also got in the Delrin I'll need to make the pump grips, I made up a big handful of my stainless detents to go with these, ran a final finish reamer down the bores and then honed each one.

I'd hoped to have at least two ready to ship out today (Monday) but I just had too much else on my plate. I still need to turn some bolt pins (and I'll probably try to get a CNC program together for those, too) and of course the valves, which I definitely want to do on the CNC. Chances are it'll be one of those cases where it'll take a full day to get the program written, then, like, 20 minutes to run the batch.

BUT... I've cleared my schedule, told most everyone not to bother me, asked the cat to hold all my calls (Elon is going to have to start solving his own problems one of these days, anyway) and anyone walking in the door is going to be metaphorically shot and proverbially buried in a shallow grave out back.

With a little luck, I think I can have at least half of these ready to head out the door by or even before Friday.

Stand by!

Doc.