Machine edge

[Gary Anhorn]

I have this fuel fill tube which requires a better taper cut on the end. Im having difficulty setting this to machine. How can I set my lathe or mill up to machine the edge more uniform. Appreciate all the help. Thanks in advance.

 

[thestelster]

Turn a wooden dowel to pipe ID, crazy glue it in, go slow, be careful.

 

[PeterT]

Kind of like what @thestelster is suggesting but maybe a slight variation depending on what you are trying to achieve. If the short segment can allow for a fixture to be inserted (blue) then you can grip that as an assembly in the chuck (black) & dress the edge. Personally I would prefer the fixture to be metal rod, aluminum should do & glued in with 5-min epoxy. I have had more consistent results with that. CA glue can be tricky on gap filling & curing metal on metal. Epoxy will gap fill & absorb machining vibration a bit better all things equal. Once machined, to remove, just apply gentle heat with gun or torch. When it turns a tan brown, it goes soft & will release nicely 90% of the time, usually cleanly. Don't use JB weld or high temp epoxy, they will hang on until the bitter end. I find heating CA the same way makes a sticky mess & hard to clean after. CA solvents/de-bonders work but very slowly.

Here are some finicky little aluminum parts I had t make at an odd miter angle which might be comparable.

 

[PeterT]

Or if maybe easier if you have a boring head, set it in mill vise & rotate cutter about the tube axis

 

[thestelster]

Or if maybe easier if you have a boring head, set it in mill vise & rotate cutter about the tube axis

View attachment 37771

I would think the set up for this would take quite a while. How to hold it so that the mouth is square in two directions; indicate center; make a chamfering tool if you don't have one; might have chatter too depending on wall thickness. I think your first suggestion would be much quicker. I don't think this is a critical part?

 

[Shoprat]

Stationary disc sander would be my choice

 

[van123d]

Would one of those pneumatic chamfering tools work for this?

 

[PeterT]

I would think the set up for this would take quite a while.

I now agree. It really depends on how accurate the little pipe segment is for either method to work. But now that I look closer at the other picture there are new issues. I assumed the part could be held in mill vise & squared on the right side (red line). But now I see the existing miter (green line) is already at an angle which would be a worse problem for lathe setup (unless its a photo distortion). If it is an angle & he wants to preserve it the whole part would have to be orientated.

Back to centering, I don't think its too difficult even if it was at an angle & presenting an ellipse viewed from top. The in-out center is mid distance between the vise jaws. The left-right center is mid point using a center finder mid span between the inner wall tangents. The boring head cutter could be ground from HSS round. All you need is one edge. But not everyone has that kicking around. Unfortunately even the small BH shanks are 3/8" dia. A fly cutter body holding a square shank tool isn't really suitable either. But now that I see that raised neck area (blue arrow) gripping in a vise is more involved. Maybe that's what you are getting at & I missed it?