RimFire Mount

[SlowHuck]

This is not a CAD drawing. Just Adobe Illustrator saved as PDF - for my use as reference and place for notes as I plan and write the g code.

My dad and I are having a friendly argument about whether I should turn the blank, drill the holes, then mount it in the mill and perform the last operations.

I am of the mindset that I would rather mill the entire piece. 1 - use this as a challenging exercise to learn g code, 2 - to accomplish its production as pure CNC, and 3 - achieve better accuracy by only having to re-mount and index the piece one time. we have the proper sized end mills to do this.

I would be interested in your opinion.

Thanks!
(P.S. This post is directed at Pale_Rider_VA, but all comments are welcomed)

[Colonel Klank]

Les: This part would be a great mill project. Let me know what order of machining you plan to use and I can help you get started.

Patrick

[SlowHuck]

	Quote: Originally Posted by Pale_Rider_Va
	Les: This part would be a great mill project. Let me know what order of machining you plan to use and I can help you get started.

You got it boss! I'll bring the hard copy to the field on Sunday and we can chat about it in real time. Meanwhile I'm gonna dust off and fire up the Sherline. Probably spend Saturday banging out a bit of code and getting re-aquainted with the little robot.

I'm intrigued with the idea of maybe starting a cottage business producing short run CNC bits within the capabilities of this shop. I searched high and low for a motor mount as in the drawing, thinking there would surely be one out there. Nada. Opportunity? Hmm...

Les

[Colonel Klank]

There certainly is room for custom parts in our hobby! I will model the mount up in 3D and we can have a look at it on my laptop at the field.

[SlowHuck]

	Quote: Originally Posted by Pale_Rider_Va
	There certainly is room for custom parts in our hobby! I will model the mount up in 3D and we can have a look at it on my laptop at the field.

One dimension I overlooked is the center of the holes for the pass-through hole for the motor screws (I have since updated my drawing, see attachment).

What CAD package you using? Corel? (ducks and runs)

[Colonel Klank]

	Quote: Originally Posted by lderby
	One dimension I overlooked is the center of the holes for the pass-through hole for the motor screws (I have since updated my drawing, see attachment). What CAD package you using? Corel? (ducks and runs)

Solidworks! (throwing vise grips)

[SlowHuck]

Cleaned up its table, dusted off and lugicated here 'n there, booted the Linux box, ran the controller software, loaded some g code, pressed "run"...

whirrrrrr... zip, zip, zip.... whirrrrr, whirrrrr.....

Wow! kewl!

(scratching head) Refreshing my acquaintance with g code programming, I figured that this piece is really pretty simple. the only real challenges are the positioning for the arc cuts on the perimeter of the piece and the pass-through holes. Now where's that damned trigonometry textbook? No, wait, they're all 120 degree angles. Piece o' cake. Still that trig book WILL come in handy.

[SlowHuck]

I think I've got a righteous solution for the indexing (I'll probably only make three of these, so the simplest of fixtures seems the best way to go):

1. Cut a small block of aluminum with a slot that tightly fits to the side on the square at the back of the motor mount.

2. prep my blanks(1.25" dia cylinder) by milling that square about .5" deep and to plan dimension on one end. The blank doesn't even have to be perfectly indexed into position.

3. mount the fixture (screwed on) to the table-mounted vice.

4. mount the blank.

5. make all the finished cuts on the BACK side of the MM.

6. Remove, flip upside down (whala! perfectly indexed!)

7. Face the original indexing stub off and finish milling the more complex front side.

If you think I'm over-complicating this, give me a ring and tell me to hold my horses.

Les

[SlowHuck]

	Quote: Originally Posted by lderby
	I think I've got a righteous solution for the indexing (I'll probably only make three of these, so the simplest of fixtures seems the best way to go): 1. Cut a small block of aluminum with a slot that tightly fits to the side on the square at the back of the motor mount. 2. prep my blanks(1.25" dia cylinder) by milling that square about .5" deep and to plan dimension on one end. The blank doesn't even have to be perfectly indexed into position. 3. mount the fixture (screwed on) to the table-mounted vice. 4. mount the blank. 5. make all the finished cuts on the BACK side of the MM. 6. Remove, flip upside down (whala! perfectly indexed!) 7. Face the original indexing stub off and finish milling the more complex front side. If you think I'm over-complicating this, give me a ring and tell me to hold my horses.

Boy! Was I ever waaaay off base with this screwball plan. Laser edgefinder all the way, baby!

[SlowHuck]

For those that are curious, here's the finished product...


Front.


Back. The only thing that detracts from a perfect finish are the vise marks.


Installed, motor mounted and ready for flight.

It's a small, simple project, but just the right challange to get me working in CNC, I'm quite pleased with the results. Thanks again Patrick. it was fun!

Next!