First milling project

[taycat]

right got chance to use milling machine at work after doing intro course on it.
boss's reason for putting me on it was since i lost use of my workshop and use lathe etc at work might as well learn milling as well.
want to make similar to ball joint splitter as in pic but bigger for removing stuck on bike cranks.
tried normal crank pullers but threads stripped in crank arm from previous person bodging them.
std car one doesn't have enough depth.
question is do i mill corners square or rounded?

 

[P. Waller]

Generous corner radii that do not interfere with the tools function is excellent practice, however it requires tooling with the desired form included which are not always available. The item pictured is forged or cast, one would not build dies or patterns/molds with sharp corners if not required.

The "sharper" the corners are on tooling the shorter the lifespan.

 

[Ray C]

The part you are showing was cast in a mold and will be difficult to replicate in a mill. Would a simple gear puller like this one be adequate? If so, it would be easier to make on a mill or, they are commonly available to purchase and do not cost much money.

Ray

 

[Bi11Hudson]

Looks like a beam clamp (cast pipe hanger) to me. I'd say stick with the above style puller if possible. A secondary idea would be a bearing puller (Harbor Freight) and a steering wheel puller. The bearing pullers get a lot of use in my shop, with many different jack screws depending on the application.

 

[taycat]

tried all my gear and bearing pullers they don't fit properly due to limited clearance.only tool close to doing it is in my pic but not deep enough.

 

[Nogoingback]

If you don't have tooling to round off the corners, you could always chamfer them. Pulling bike cranks doesn't seem
like all that tough a job with a tool that fits properly.

 

[taycat]

proper tool won't work as someone in past as stripped threads in crank arm.
last one i had to put in press at work to get it out think king kong had tightened it up.
i get the bikes from tip usually to build fun ones for kids.
bit like below.

 

[Bi11Hudson]

That first one looks cool, like it could cover a couple of miles with serious grades. The one I built is a little bigger, I'm 6'3". But with the frame stretched, I think it would work. The third wheel in the back for more stability is the best.

The type of puller I was referring to could be built easily enough. A link to the HF version is at:
https://www.harborfreight.com/catalogsearch/result/index/?dir=asc&order=EAScore,f,EAFeatured+Weight,f,Sale+Rank,f&q=bearing+puller
A photo, if I can make it work this time. The photo looks like hell but gets the point across. It can be used in either direction. I have several, a couple still in the original configuration. Very useful, all in all. This photo is what I wanted to send earlier. Circumstances prevented its' working the first time. I have no idea why it doubled up........

And for what it's worth, if you do build one of those things, make the ends plenty thick. No reason a weldment shouldn't work, at least a couple of times. If it breaks, make another one. As for the corners, what corners? And why mill it unless to get the practice? Don't worry about "pretty", just get it working.

Bill Hudson​