The Offcial Machinist Thread: Revised 01/04/2014

[evilvet]

I has new supply of HDPE

• HALO image from Sketchup
  40 minutes of CAD/CAM
  One hour on the mill
  Needs polishing and finishing properly

[Zeus]

Looks good mate, if you need to just smooth it over a bit, just running a heat gun over it should slick it up a bit.

[evilvet]

Yeah, heat gun or a Dremel with a sanding drum is the current option.

My longer term plan is to add a fourth axis to the mill, then all is good.

Right now i can do pretty much any regular solid, if it has a symmetric axis in at least one plane then all is good. i create the part as a 3D object then split it into two halves, after milling they are glued or screwed as shown into a complete unit.

The process is pretty straightforward.

• Create or acquire the object as an STL file
  Load it into CAM and perform a series of X axis slices at the range of 1-2mm depending on the level of detail required
  Delete all polylines below Z=0
  Create MOP's to suit the remaining polylines
  Copy and past the result and then do a Y axis transformation on the copy
  Edit the Z axis points on the copy to create two "flat" 2.5D results
  Machine then laminate

Crude but effective.

[jackssmirkingrevenge]

noice!

This is for "Apocalypto"?

[evilvet]

Yep
Stock is next, I think I need to add a fourth axis sooner rather than later.

Anybody got a lead on a cheap self-centering chuck they want to sell......

[Zeus]

JSR's spark gap came it, and I can't recommend him enough, excellent quality, checked the electrical leakage at 500 volts, absolutely nothing. Still sparks with a grill piezo igniter at 23 bar. Haven't had a successful shot yet, but that's just because I haven't really tried.

The only suggestion I have (which I forgot in the PM) was to back out the tap a bit more often, doesn't affect it at all, you just see some tiny little burrs. Either that or it's a little bit dull, but it's no problem.

[jackssmirkingrevenge]

For some reason this particular tap is a bit iffy, I never managed to get fully satisfactory results with it. One eighth BSP would have been prettier, but as I understood less convenient for you.

[evilvet]

And fabricated a jig that allows me to flip a part accurately around the XYZ centre.

And the first result is..........

A 1/4 scale model of a 62 Stratocaster.
I have a couple of mates into their music in a big way so did this for a laugh.

[jackssmirkingrevenge]

tres cool! is that wood or foam?

You know, many members on here would pay good money for CNC cut stocks...

[evilvet]

It's MDF, 16mm stock.

Something like this maybe.

Happy to make one up for testing purposes, anybody got some suggestions ?

Maximum dimensions would be 600mm long and no more than 40mm total thickness. The obverse and reverse can have different detailing, even engraved lettering if that floats your boat.

The main issue is getting a suitable 3D model. The one below was taken from a Google Sketchup model of (allegedly) a Remington 700, then exported as an STL format file for CAM processing. Each surface generates about 80,000 lines of code for the CNC mill to chew on. I can produce something to about 0.1mm accuracy, that's about 4 thou for you non-metric types, the result really depends on the tooling and the material.

[jackssmirkingrevenge]

There are plenty of folks handy with 3d here so I don't see modeling being a problem.

Here's a thought, how about designing a starter kit for noobs?

An eBay shopping list with cheap QEV, blowgun pilot etc. and a clamshell CNC stock to go with it which holds everything together...

[evilvet]

Yeah, great idea in Oz with our gun laws.

Hey Zeus, wanna be cell buddy with my new best friend, the 150kg Islander with a poor hygiene plan.

No thanks, I will machine bits of plastic for toys all day long, or even wooden gun stocks so the kids can play cowboys and Indians; DIY free trips to the County Court, no thanks.

[Zeus]

What, you expect me to hold him down while you...

Ahem.

Distribution is no concern within Aus, I'd be happy to take care of that at cost. But we've been discussing something a bit lower risk, and higher return.

[jackssmirkingrevenge]

No thanks, I will machine bits of plastic for toys all day long, or even wooden gun stocks so the kids can play cowboys and Indians; DIY free trips to the County Court, no thanks.

I don't think it's as risky as you think.

First off, it's a piece of wood. You can't be prosecuted for mailing someone a piece of wood.

Secondly, there is a whole world beyond Australian borders that you can sell to without legal concerns.

My idea would be to draw up a list of parts that can be easily and cheaply purchased online in order to make something like this:



Dewey would naturally be a huge help here

All that would be left is to design a stock, something in two halves with grooves to accomodate the worky bits in between.

lower risk

Very out of character

[evilvet]

VICPOL Official:

From 1 July 2011, an imitation firearm will be defined as "a device, the appearance of which could reasonably be mistaken for that of an operable firearm, but which is not designed or adapted to discharge a shot or bullet or other missile by the expansion of gases produced in the device by the ignition of strongly combustible materials or by compressed air or other gases, whether stored in the device in pressurised containers or produced in the device by mechanical means and is not capable of being made to do so".

Have a read of this
http://www.police.vic.gov.au/retrieveme ... tus=active

and welcome to our world.