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Engine case seperator

#1
AND I started making parts that actually DO something and work the way it was intended.

To most of you this is silly simple, but again for me, it is all ground breaking :)

First I needed to make a thread adapter.

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Pretty simple, M12x1.25 on one side and 1/2-20 (or 13) on the other side.

What I learned from this, is that twist drill bits are not accurate at all :) And they tend to oversize the hole.
Also learned that I need to learn to make my own tiny boring bars and how to use it.

Next was a couple of plates.
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It seemed simple enough, but I learned that either my DRO is sticking or I have WAY too much slop in my table on my mill. It is close enough to what I needed by some of my measurements were off by 10 thou which I need to fix and clean up.

Here is the finished pieces in action

YAAAA it did something!

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#3
Looks like it does the job you needed it to so it's a success. What is the engine from?
A Dirtbike
Buddy bought one that was trashed and is trying to rebuild it. It broke a piston rod and the half that was still connected to the crank acted like a hammer and blew a couple holes through the casing. Its a BIG repair job. But if we can do it all in the home shop and he doesnt have to buy many parts then it will be worth it.
 
#8
Tig welder is on my "to get" list
But right now isnt an option.
(Ive done, GMAW, Stick, O2-C2H2, Carbon Arc, but never Tig.... really want to try it)

Its not my personal bike. It is a friend of mine. He is a Manufacturing Engineer. So if he is OK with his methods.... who am I to argue :)
 

Everett

Active Member
#9
Nice to see you're using your new-to-you machine! That part looks pro. My only raised eyebrow from the pictures was the engine case on the kitchen table - if you have a Better Half, is she out of town at the moment?? :eek:
 
#10
Nice to see you're using your new-to-you machine! That part looks pro. My only raised eyebrow from the pictures was the engine case on the kitchen table - if you have a Better Half, is she out of town at the moment?? :eek:
Lol
I noticed that too. That was my buddy using the tool at his house. So IM in the clear.
 
#12
Nice! The plates turned out well. Look matched. How did you thread the inside of the thread adapter?
I used plug taps. So because of this I made the adapter a little longer, basically we had good thread engagement on boths sides except for the middle 20%, that was just a cluster of overlaping threads. Had to do it that way because it was plug taps not bottoming taps.

I drilled the smaller hole first all the way through the work on the lathe, left the jacobs chuck in there and just pulled out the drill bit and put in my tap and then just hand turned the chuck to do the tap. Perfectly straight. Then flipped the part, went to drill it to the larger hole only to discover again that drill bits suck and the first drilling operations was larger than expected so I was able to just go in and tap the other side without resizing it.

Hopefully you were able to follow my chaotic thoughts.
 
#13
Nice! The plates turned out well. Look matched.
Yeah.... they werent lol

If you looked closely there were some errors you could see with your eye easily enough. If I wanted them perfectly matched I would have done them together..... but I did it one at a time so I could try different techniques. It was not overly critical and allowed for slop.
 
#14
To those more interested in the engine repair. Here is some of the repair we just finished. The shift shaft and the holes in the transmission case where damaged.
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So we drilled down a little deeper and opened up the hole a little bit. This is so I could make a new sleeve that would have a slight interference fit below the old broken sleeve.
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This peice needed to have a very small but precise shoulder and internal diameter. So this was my first swing and using a boring bar. Worked perfectly though.

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My shaft still had a very slight taper to it but I think that’s the alignment of my tail stock which I have not done tuned yet. But that should be fine as I need to custom make the other side anyhow. The main peice that slides on the shaft does so perfectly.
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I’m happy with the finish on the shaft. Looks factory ;)
 
#17
Debating between that barring locktite or just JB weld it in there.
Yes those would have been my first two choices as well. While I have had really good luck with JB Weld in the past, I would be slightly concerned about it letting go someday if surface wasn't perfectly cleaned or something and then there is a chunk of JB Weld floating around. I think I would opt for the loctite if I had the type that was suited to oil immersion. Loctite is fast, easy and it holds incredibly strong. I've destroyed pieces taking them apart that were held together with permanent loctite. A dab will do ya.
 
#18
Yes those would have been my first two choices as well. While I have had really good luck with JB Weld in the past, I would be slightly concerned about it letting go someday if surface wasn't perfectly cleaned or something and then there is a chunk of JB Weld floating around. I think I would opt for the loctite if I had the type that was suited to oil immersion. Loctite is fast, easy and it holds incredibly strong. I've destroyed pieces taking them apart that were held together with permanent loctite. A dab will do ya.
We built a new barrel for my Race 10/22 for steel challenge.
Took a barrel liner and have it "glued" in some 7075 aluminum with that special locktite.
Its going NO where. That stuff is magical.
 
#19
Update for those interested.

The next step was to repair the threaded hole that got blown out.

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So, I set it up in the mill and opened up that threaded hole to about .375 with my 3/8 end mill to a depth of 0.7"

Then we made a new dowel that was 0.6" long, .344 in diameter and then threaded the outside of it so it would give the JB weld something good to hold on to.

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I missed out on taking a picture of what the dowel looked like in the drilled whole. But here it is after it was JB welded in place. (And after our pilot started)
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The hole was drilled and tapped to M6x1.0

So far the JB welds are sealing against water so it should be fine to hold the oil in.
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Just some fine tuning left to do. Almost at the stage where we can put it back together and fire it up. The true test.
 
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