Chucking a Piston in 3 jaw lathe chuck
- Thread starter drf255
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cuttinties
ArboristSite Guru
Through the center of your chuck you push a bar and tighten up. You'll use a wrist pin slid through a hole drilled in the bar. Place the piston on the end of the bar, push the bar through pull snug and tighten the chuck. The flat part of the skirt will be on the chuck with the draw bar being held, not the piston. I would give a better description but I don't really have time until this evening.
drf255
BAD CAD
Think mine is bronze bushed
Mike Gott
ArboristSite Guru
The draw bar method works well, I've only cut a couple chainsaw pistons but have cut lots of pistons for pulling engines this way. I also made a hand mandral for cutting the squish chamber after reading Tree Monkey's post, tried it on a test cylinder and worked well. Good luck! I'll try to post some pics this weekend when I start my 2186 project along with asking a bunch of questions for experts, it will be my first full porting job doing all the work myself
caffeine1fg
ArboristSite Operative
Here is my setup, all done on a lathe except for the milled slot in the arbor.
Mike Gott
ArboristSite Guru
That's looks real nice!
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
tree monkey
Addicted to ArboristSite
I made steel collets
drf255
BAD CAD
Is that how you cut your popups?
drf255
BAD CAD
Ordered 4 jaw chuck, boring bar holder with bar and cutter.
I'm all in for around $500 for a small atlas lathe.
Don't think I did too bad.
I'm all in for around $500 for a small atlas lathe.
Don't think I did too bad.
drf255
BAD CAD
So I found and purchased a 4 tooth chuck.
The chuck is non self centering. Each tooth moves individually.
My lathe shaft doesn't have a dead center in it.
How does one find centerline here?
The chuck is non self centering. Each tooth moves individually.
My lathe shaft doesn't have a dead center in it.
How does one find centerline here?
I like to setup the indicator on top of the part like this guy, most people seem to set the indicator off to the side. Also, a back plunger indicator is handy and stays out of the way of the chuck wrench. You may want to look into some night classes at a local tech college, a few hours a week with a skilled machinist/tool maker showing the basics would help a lot.
drf255
BAD CAD
I'm not foolish enough to expect precision machine work to be fast and easy.
You are on your way to being a good machinist!
super3
Addicted to ArboristSite
A bit quicker than the vid posted above.
Make an indicator holder for the tool post to position the dial indicator in the center line of your material.
Find the low point and zero the dial there. Now rotate to the high point. Move the dial to 1/2 of that reading, rotate the chuck (forward rotation) to the nearest jaw. Use 2 chuck keys on the jaws opposite one another and move both jaws together to zero on the dial. Rotate chuck to the next jaw and repeat to zero on the dial.
Make an indicator holder for the tool post to position the dial indicator in the center line of your material.
Find the low point and zero the dial there. Now rotate to the high point. Move the dial to 1/2 of that reading, rotate the chuck (forward rotation) to the nearest jaw. Use 2 chuck keys on the jaws opposite one another and move both jaws together to zero on the dial. Rotate chuck to the next jaw and repeat to zero on the dial.
jar944
ArboristSite Operative
drf255
BAD CAD
Yes. I saw a video of that on Youtube this am. Looked easy, but then again...
Biggest fricken problem I got is that I'm fixing the lathe and could do it myself if I had another lathe! I coulda repaired some parts instead of replacing them.
super3
Addicted to ArboristSite
Quickest way I have found.
Don't we know. I am fortunate enough to have access to another lathe 1/2 mi away to make parts for mine.
Chris-PA
Where the Wild Things Are
I guess I'm not sure why a 3 jaw isn't good enough. I just used one to do the pop up on my Poulan clamshell. I cut a piece of 0.010" Nomex paper we use here and wrapped the piston with that - it's tough and kept the surface from marring. I had to fiddle with it to get it oriented flat - I put an old exhaust valve in the drill chuck on the tail support so I would have a good perpendicular reference so I could get the wobble out of the face.
The requirements for centering the pop up are not really very severe. The combustion chamber is not usually machined and you're going to want some clearance - so what if it's +/- 0.005" or even a bit more?
The requirements for centering the pop up are not really very severe. The combustion chamber is not usually machined and you're going to want some clearance - so what if it's +/- 0.005" or even a bit more?
drf255
BAD CAD
I got the 4 jaw to spin jugs.
