CNC miller instead of laser cutter?

Location
Manchester
Hi Martin,

When I don't pay any attention to your forum lots of things happen! I am impressed with what you have achieved with the milling cutters and if I didn't have a laser cutter I could be sorely tempted by that - will it cut brass easily?

I have been using shellac a lot for a couple of years now and usually buy it in 1 litre containers, when making things in card it stiffens it very well so I tend to be very liberal with it - you can never apply too much. I laser engrave brickwork on 0.2mm card (ordinary office card) and it retains the mortar lines regardless of how much I apply. Currently the one I have in the workshop is this one and I spent about £15 to get it if I recall but I have had it for a year or more now.

Very interesting work and I will follow with great interest.

Ralph

20210929_103344.jpg
 
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Martin Wynne

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will it cut brass easily?
@ralphrobertson

Hi Ralph,

I haven't tried it on metals yet. These machines are sold as wood routers and engravers rather than metalworking machines. Likewise the Chinese cutters sold for them (which are a lot less expensive than proper HSS milling cutters). But for what it's advertised as, it seems to work very well.

But it's certainly lightweight, especially the motor spindle and Z-drive. Beefier machines are available at greater cost. Also machines with a much larger table area.

However, I'm confident it could do typical model milling in metals, provided you take your time with very light cuts.

But brass comes in a huge variety of grades and compositions. Some of it is very "chewy" and difficult to machine cleanly. What you want is CZ121 Free-Machining Brass which contains 3% lead to aid machinability.

More about grades of brass at: https://www.metals4u.co.uk/blog/brass-in-depth-guide

It might be wise to start off with aluminium alloy in preference to brass, or even a nice free-cutting mild steel, to get a feel for the machine.

For more about these machines, there's a great series of videos from James Dean, a knowledgeable UK guy with a nice Midlands twang for a change:

https://www.youtube.com/c/JamesDeanDesigns/videos


Notice that his machine doesn't have the manual handwheels on the lead screws. It's well worth paying a little bit extra to have those. My machine also came with several of the items he describes as extras -- the offline controller, rubber feet, spiral wrap for the cables.

Thanks for the info about the shellac sealer. So far I've used the water-based version, for use with a water-based wood stain, but I will try the spirit-based sealer and compare results.

cheers,

Martin.
 
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Wayne Kinney

Member
Location
UK
Nice work, Martin.

I have been milling the finetrax n gauge bases on a CNC mill for years but from 1mm thick black HIPS sheet. This could possibly give a better result?
milled base.JPG

This is my CNC machine milling some "concrete" bases for flat bottom N Gauge. This is light grey 1mm thick HIPS sheet.
 
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Martin Wynne

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Location
West of the Severn UK
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Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
Nice work, Martin.

I have been milling the finetrax n gauge bases on a CNC mill for years but from 1mm thick black HIPS sheet. This could possibly give a better result?
@Wayne Kinney

Thanks Wayne. That's very good. And fast! :)

HIPS or any other plastic sheet would no doubt cut nicely. But I'm not actually interested in building any track myself. My interest is in developing and testing the Templot 3-D file exports, exploring the possible options, and showing Templot users what is possible. If anyone opts to get a CNC miller it's obviously up to them what materials they choose to use.

MDF or plywood makes a nice solid base for 4mm scale. Maybe a sheet of plasticard could be laminated to the surface of MDF and cut away on the miller for a nice clean cut. Likewise the iron-on hardwood veneers. Some modellers do prefer the texture of real wood for the timbers. Even MDF has a wood-like surface texture after staining.

But my main purpose in this topic was to show that the little Chinese CNC engravers cost a fraction of the cost of a laser cutter, but can do some comparable work. They can't cut square internal corners of course, but against that they can use thicker materials and cut variable depths for pockets, rebates and slots. And also be used as a jig borer, and for light manual milling and drilling. Laser cutters can do square internal corners, but the home machines are limited in the thickness they can cut, and generally it is cut all through or nothing -- no blind pockets or rebates. And they cost. Horses for courses.

Also of course this is a big distraction -- I started intending FDM-printed track bases, and I must get back to them. :)

cheers,

Martin.
 
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Martin Wynne

Admin
Location
West of the Severn UK
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Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
But it's certainly lightweight, especially the motor spindle and Z-drive. Beefier machines are available at greater cost. Also machines with a much larger table area.

However, I'm confident it could do typical model milling in metals, provided you take your time with very light cuts.
@ralphrobertson

Hi Ralph,

As I was writing that, a beefed-up version of the 3018 machine suitable for metal-cutting was being released, although not yet in the UK:

https://www.sainsmart.com/products/...20-pro-max-diy-kit-for-metal-carving-and-more

They refer to metal-carving rather than metal cutting. I'm not too sure what metal-carving is -- do folks sit around a camp fire whittling away on a block of aluminium? :)

Notice that it has some (tiny) handwheels, although on the X-axis you are assumed to be left-handed. Here's a review:


cheers,

Martin.
 
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Wayne Kinney

Member
Location
UK
I would say by 'carving', they mean 'engraving'. Just scribing into the material.

The above machine looks far more flimsy than my (old) 3040 machine, as even this is not up to the job of cutting metal of any kind.
 
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Location
Manchester
Thanks for advising me on the CNC machines. Discovered that a colleague in the club has a machine that WILL cut metal so at least I can probably try something out before I consider a purchase. I have loco mainframes in mind, will save me having to produce a test etch.

Ralph
 
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