[acannell]

I've been using my 3 axis mill for about a year now and have made quite a few things on it and made some money using it to. All in all its been great.

But I've yet to really machine anything that needed to be precise..all the stuff I made was more "shapes" then surfaces that interacted or assemblies with moving parts. By precise I mean accuracy of 0.0005 or below.

I'd really like to start making precision things, just for fun, and to improve my setups and fixturing methods.

Whats a good project for this?

I like the idea of gears or things that need bearings and do something.

Perhaps a right angle head for the mill, attempting to get it as precision as possible? I dont mean making a commercial grade one obviously..but however close I can get.

This is also a good excuse to buy precision measurement and other related tools so I can actually prove things are correct lol

Anyone else feel this way?

[awerby]

What kind of a mill have you got? Most of us hobbyists are happy to hold total tolerances of +/- .001" Getting to .0005" (not to mention below that) takes a lot more effort and money. Just measuring things to that precision takes a big investment, and every little thing starts adding up, like temperatures, tool deflection, and surface roughness.

If you're looking for projects requiring mechanical parts, you might check here: Home Model Engine Machinist

[acannell]

What kind of a mill have you got? Most of us hobbyists are happy to hold total tolerances of +/- .001" Getting to .0005" (not to mention below that) takes a lot more effort and money. Just measuring things to that precision takes a big investment, and every little thing starts adding up, like temperatures, tool deflection, and surface roughness.

If you're looking for projects requiring mechanical parts, you might check here: Home Model Engine Machinist

I think I might end up needing to get a lathe.

But I'm still curious how accurate I can get things using just the mill and really engineering the setups to where things are concentric and surfaces are at controlled angles. I just need a good excuse to attempt it. Most of the stuff I actually use the mill for is unlikely to need thou precision.

I would like to make a gerotor pump which should need some tight tolerances, but that may be not such a good thing to spend time on since I can just buy the rotors.

I'm thinking a tool for the mill like a speed multiplier or an angle head would be really worth the effort. They are expensive and very useful and definitely a challenge as far as precision..

[forjay]

How did you make out with your task?

[RICHARD ZASTROW]

You could make a motorized spindle for a DIY lathe or mill.That requires precise ID bearing bores in alignment with other surface geometries. The spindle shaft requires the same degree of precision for the bearing seat OD's. Now you'll be dealing with microns (.000039") for bearing fits. Then you'll have experience in precision machining.LOL

Dick Z

[acannell]

You could make a motorized spindle for a DIY lathe or mill.That requires precise ID bearing bores in alignment with other surface geometries. The spindle shaft requires the same degree of precision for the bearing seat OD's. Now you'll be dealing with microns (.000039") for bearing fits. Then you'll have experience in precision machining.LOL

Dick Z

I like this, basically I'd be making something the size and precision of a sherline headstock, and I have one of those, so it might be interesting to compare.

Theres a couple things missing though..I dont really have a use for a spindle since I already have a lathe and mill..although I'm sure a more complex project would incorporate a spindle block like this.

And how do I actually confirm I've done it right? What tools do I use to measure bore to bore concentricity in a block like that?