Author Topic: The "2-Bits" V-Twin  (Read 10529 times)

Offline Roger B

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Re: The "2-Bits" V-Twin
« Reply #15 on: March 02, 2022, 06:23:18 PM »
I am a fan of holesaws to save materials  :)
Best regards

Roger

Offline kuhncw

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Re: The "2-Bits" V-Twin
« Reply #16 on: March 02, 2022, 07:34:02 PM »
Nice to see a Taig lathe hard at work.

Chuck

Offline RReid

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Re: The "2-Bits" V-Twin
« Reply #17 on: March 03, 2022, 01:13:49 AM »
Quote
Very nice length of pipe you made there, Ron!
Thanks Kim! But if you get the contract to re-plumb the city of Portland, I don't recommend you use this method to get your pipe! :Lol:
Thanks Roger! I'm also a fan of saving materials as much as possible.
Thanks Chuck!

Before starting work with the milling machine, I thought it would be a good time to check the tram. Here's my set-up. The piece of glass serves as a surface plate.


I made what I call “tramming jacks” not long after getting the mill, which are little more than a pair of machine screws and nuts. Since the Taig has one of those columns that pivots on a single large bolt, they really help in getting it set, as well as add extra support at all times. The nuts rest in a groove in the green base plate so they don't rotate. The screw heads are counter-bored to take little steel pads that are free to rotate in the bore and slotted at the top to fit the wall of the column tube. Then the screw can be turned with a wrench to raise or lower either side as needed. You can see one in under the column in the phote, near the end of the wrench. They work well, but happily very little adjustment was needed.




With that done, I set up to mill the cylinder landing flats in the crankcase. The first one is the easy one, it can be held in the vise flat on the table. I have the vise mounted to the tilting table though, so that I can roll it up through 50 degrees to do the second one.


Once the flat was finished I bored the hole the cylinder will plug into, and drilled for two 6-32 fixing screws.




Once I rotate it up for the second flat, I'll have just enough Z height left to mill the flat, but not to do any drilling or boring. That should be OK, since the flat will be there to key off of. I'll just reset the vice with that plane horizontal.
Regards,
Ron

Offline kuhncw

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Re: The "2-Bits" V-Twin
« Reply #18 on: March 03, 2022, 03:19:37 AM »
Ron,

Thanks for the tramming jacks tip.  My CNC mill is a Taig.  The jacks will work much better than tapping on the column to make adjustments.

You are off to a good start on your engine.

How do you like the little boring head?  Sherline product?

Chuck

Offline RReid

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Re: The "2-Bits" V-Twin
« Reply #19 on: March 03, 2022, 03:29:25 PM »
Thanks and you're welcome, Chuck. Glad you like the tramming jacks.

Yes, the boring head is from Sherline. Unlike the Taig version it has a screw adjuster, so is easier to use, though the adjustment is low precision. If the bore size is critical it's a matter of cut/measure/repeat and sneaking-up slowly (but I do that anyway, so what else is new?). For my purposes it does work very well. I like it.
Regards,
Ron

Offline Hugh Currin

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Re: The "2-Bits" V-Twin
« Reply #20 on: March 04, 2022, 12:35:14 AM »
Yes, the boring head is from Sherline. Unlike the Taig version it has a screw adjuster, so is easier to use, though the adjustment is low precision. If the bore size is critical it's a matter of cut/measure/repeat and sneaking-up slowly (but I do that anyway, so what else is new?). For my purposes it does work very well. I like it.

I did not have much luck with the Sherline boring head. I finally broke down and bought an "S-1 1/2 A" Criterion boring head. Not extremely expensive on EBay.


I haven't used it extensively, but better quality and much more pleasant to use.
Hugh

Offline RReid

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Re: The "2-Bits" V-Twin
« Reply #21 on: March 04, 2022, 01:07:21 AM »
That looks like a real nice boring head, Hugh. One for the wish list, but for me not yet at the very top.

Here's the set-up for milling the second cylinder flat. In this view the mill head is virtually at the top of the column. Enough room left to do the job and even a bit of extra.


Contrary to what I said in the previous post, I was also able to pilot drill for the center hole and tap drill for the two cylinder mounting screws.


With that done I rolled it down to 25 degrees and milled a flat between the cylinders. This is not really necessary, but I drew it that way and it may come in handy later as a reference plane for orientation, such as when attaching the “legs”.


Lastly, I dropped the tilting table back down flat and re-set the part in the vice so the flat was horizontal  and perpendicular to the column. I did this both with a square, as shown, and by rotating the boring head (backwards) by hand with it just touching the surface, to ensure that it contacted evenly all the way around. Then I finished drilling and boring the center hole.



Regards,
Ron

Offline Roger B

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Re: The "2-Bits" V-Twin
« Reply #22 on: March 06, 2022, 07:40:46 AM »
That's a nice setup to get the angles correct :ThumbsUp:  :ThumbsUp:  :wine1: I guess you found enough headroom for the second cylinder mount by holding the drill in the collet rather than using a drill chuck.
Best regards

Roger

Offline RReid

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Re: The "2-Bits" V-Twin
« Reply #23 on: March 06, 2022, 03:00:35 PM »
Thank you, Roger!

Yes, holding the drills in a collet was the only way. Changing the drill bits without moving the table away was a close thing, even with the stubby drills I prefer. Of course center drilling was easy enough, the tool being so short, so I knew I'd be able to at least do that.
Regards,
Ron

Offline RReid

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Re: The "2-Bits" V-Twin
« Reply #24 on: March 07, 2022, 12:42:44 AM »
In order to keep the crankcase from rolling around like one of these guys  :ROFL: a base/pedestal/standards/legs/whatever is needed. I'd drawn a kind of saddle arrangement with a pair of bars cut to match the curve of the crankcase at the top with integral legs extending down from that.

To cut that 1.5” radius curve, I considered several possible methods, including bolting the bar stock to the face plate on the lathe, or using the flycutter on the mill as a boring tool. But when I realized that I have a 3” OD hole saw, I decided to take that approach a second time. It would only need to go through 5/16” bar, so much easier than the crankcase job. I left the bar stock plenty long to make clamping easier.


That turned out well, so next I went to the mill to take a light flycut across one surface and cut the pieces free from the bar stock, still leaving some extra to trim in the next step.




Now the two parts were stacked with the arcs concentric, the edges were trimmed square and to size and the legs were cut in.




The finished articles are screwed to the crankcase from below with a pair of 4-40 button head screws each.

Regards,
Ron

Offline Mike Bondarczuk

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Re: The "2-Bits" V-Twin
« Reply #25 on: March 07, 2022, 09:12:32 AM »
Very novel and practical approach to attaining symmetrical base components  :thinking:. Am watching with great interest being a Vee twin rider myself.

Mike
"Everything I can't find is in a totally secure place"

Offline RReid

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Re: The "2-Bits" V-Twin
« Reply #26 on: March 08, 2022, 12:56:53 AM »
Thanks Mike! I assume that's the bike in your avatar? What is it, I can't make out the writing on the tank in that tiny image.

This afternoon I made a start on the first of the cylinder sleeves, for a change of pace after all the aluminum work on the crankcase. The sleeves are 12L14 steel and I borrowed the basic design from the Upshur engine with only minor changes in dimensions to suit this engine.

After cutting off a 3" long blank, I drilled the center out to 1/2" on the drill press, then chucked it up in the lathe to turn the "upper" OD. An aluminum cylinder block with all the fins and the exhaust valve housing will slip down over this portion.


Then I set up the steady and bored the cylinder. The nominal bore is 0.75", but I was happy with the finish at 0.748" so left it there. The pistons will be turned to fit, so the finish is more important to me than the last ooonnch of precision around a fairly arbitrary number!


I finished by reversing the part end for end in the chuck and getting it all dialed back in. Tomorrow I'll turn the short section that plugs into the crankcase and finish it off to length. Then do it all over again for the second cylinder.
Regards,
Ron

Offline Mike Bondarczuk

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Re: The "2-Bits" V-Twin
« Reply #27 on: March 08, 2022, 08:07:08 AM »
Hello Ron,

The bike in the Avatar is a nickel plated 1960 Norton Wideline frame housing a heavily modified 1959 Triumph Bonneville engine. The front end is Ducati with twin discs and the rear end is a one-off with another disc and some fancy shocks.

Its history is a bit chequered though it has been raced in Clubman events on the IOM and still bears the scrutineering marks from its various forays, plus a slightly damaged, though repaired, petrol tank.

Not the most comfortable bike to ride though quite exciting when on full chat, and the reference to the Vee Twin is my 1999 "bobbed" Harley Sportster, minimal chrome and lots of deep gloss black, and I will try to post some photos.

Mike
"Everything I can't find is in a totally secure place"

Offline RReid

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Re: The "2-Bits" V-Twin
« Reply #28 on: March 08, 2022, 03:25:18 PM »
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The bike in the Avatar ...
That sounds like a very interesting bike! In the sports car racing world here in the U.S. we would have called that a "special".
Regards,
Ron

Offline RReid

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Re: The "2-Bits" V-Twin
« Reply #29 on: March 09, 2022, 01:10:37 AM »
Sawing off the blank for the second cylinder sleeve. Otherwise known as the MEM Upper Body Workout.


And drilling prior to boring. This is one of those highly technical steps that I neglected to show in the last installment.


My wife wants to turn it into an Easter Bunny.  :ShakeHead:



Regards,
Ron