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My lovely wife kindly bought me a Stepcraft 420 for Christmas and Birthday (probably for the next ten years!).

 

It arrived as a kit of parts and an instruction manual, which took an out two and a half days to build up (carefully and conscientiously). The instructions were actually very accurate and good, and the manufacturing quality of the machine is superb throughout.

 

I wanted the 420 instead of the bigger machines in order to mill loco frames etc.., rather than to carve large pieces of timber, so a smaller size equals more rigidity (they use the same extrusions) and also take up less space. The 420 works a nominal A3 work-piece, which is more than adequate for me.

 

The assembly went together with no problems- and very little confusion - every piece fitting together extremely well. The profiles pieces are 10 and 12mm aluminium, and the extrusion are a heavy section aluminium, cut perfectly square. The End result is a very rigid, back-lash-free machine, which I'm hoping will produce accurate work reliably.

 

Software however has been difficult to get going- insofar as the supplied disc corrupted and left me having to do work-arounds, which I did manage to do successfully eventually - but it has taken me three days from completion to getting things moving under control.

 

Having said that, I have just pretend cut (without a tool) a loco frame successfully, with the machine doing absolutely everything it should. I am therefore extremely pleased with it, and looking forward to actually cutting metal. I will obviously break a few tools learning the best parameters, but that is par for the course (I need to use 1.2mm cutters for much of the work...)

 

27656790279_dded7690e6_c.jpgStepcraft 420 by giles favell, on Flickr

 

 

39433908741_2e6eee25fa_c.jpgStepcraft 420 by giles favell, on Flickr

Edited by Giles
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Look lovely.

 

I can see how the left-right and up-down movement is accommodated. But I can't see where the front-back movement happens?

 

...R

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The front to back axis (Y) is the two major vertical arms - they traverse back and forth via a lead screw on both sides within the side extrusions. It's a beautifully engineered bit of kit!

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 It's a beautifully engineered bit of kit!

Indeed. I couldn't see the joins.

 

...R

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A Stepcraft is on my wishlist too in the coming years. So thanks in advance for all experiences, hints and tips you will hopefully post here!

 

Michael

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I've often been interested in this machine and others for the same purpose - loco frames milled.

 

However can it cut metal up to 2mm's thick??

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Because our priority at home is to get ready for a living room extension, I've not had time to play.... (as well as trying to earn a living!)

 

It can happily carve it's way through 12mm aluminium (eventually - multiple passes) . Yes, it's a fairly serious bit of kit. I certainly plan to use it on brass and nickel silver.

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Sounds good, 12mm thick alluminium sheet? If so wow is all I'll say.

 

How is the software to learn? This is my biggest worry because some programs I can work out others I end up pulling my hair out with tutorials that are just above me.

Also what file types can it understand?

 

It'd be a whole lot easier if I can just bung an STL in there without having to find awkward ways of converting it with other programs.

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I bought VCarve with it... i have an Emblazer laser which runs Cut2dlaser, and this is of the same family. I therefore found it extremely to use, being able to import a DWG and allocate vectors straight away without any difficulties. This file was then imported into UCCNC and instructed to run which it did do with little difficulty.

Edited by Giles

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I've finally had time to have a quick play. I cut a pair of frames in 28 thou nickel-silver for another 7mm 2ft gauge Bagnall, as I had them drawn up anyway.

 

I broke quite a few cutters trying to sort out the feed rate, but eventually got it sorted for the moment.

 

 

The result is very clean, consistent and accurate to within +/- 0.02mm or so, which is sufficient for me. In fact - I'm very pleased.......

 

https://youtu.be/sqUg5IDuIO4

 

https://youtu.be/sqUg5IDuIO4

 

I first cut a little square drawn exactly 15mm

 

40502087331_48e8cda5dc_c.jpgTest piece. Should be 15mm by giles favell, on Flickr

 

39792040324_990e377f1b_c.jpgCutting test piece by giles favell, on Flickr

 

39792620474_16a686121f_c.jpgMachine cut frames by giles favell, on Flickr

Edited by Giles
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I broke quite a few cutters trying to sort out the feed rate, but eventually got it sorted for the moment.

 

 

 

Giles,

 

I know the feeling. :-)  When I started milling metal with small diameter carbide cutters (0.5mm, 1mm) the attrition rate was high,  and expensive. :-)   But I eventually worked out feeds and speeds which gave a reasonable cutter life.   The 7000 rpm top speed of my spindle is technically too slow for small diameter cutters so I finished up working in a grey area outwith manufacturers' recommendations.

 

But you are now enjoying the benefits of CNC - producing parts to an accuracy which could be impossible by hand and all at the press of a button. :-)   And a CNC machine is a great help in fending off the ravages of Shakespeare's seventh age of man. :-)

 

Jim.

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Yes - a removable (ish) double sided tape. It was recommended by Roy Link for pantograph milling, and it's what I use with my little converted Proxxon Pantograph engraver/miller. I thought I would default to the same technique, since it's fundamentally the same thing. It works very well, with no apparent down side.

In my vast experience of one test....

Edited by Giles

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Hi Giles, what material is underneath the workpiece - does the mill cut into this too? I keep looking at this and other CNC threads, and am becoming more and more tempted!

Edited by jdb82

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I'm just using an offset of melamine shelf... the machine is accurate enough to cut into to double sided tape, but nomlower - although i am using the melamine as 'sacrificial ' and safe to cut into.

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Please just a quick question as I too am saving up for (likely) a Stepcraft CNC gizmo.

 

How much learning of the programs or actual programming is there?

 

Lets say the machine is assembled on the desk and the program/s installed.

 

Import a drawing file lets say.....now what?

 

Is it rather like a 3D printer where you input a few variables and it just gets on with it or is there a lot to learn and lots of pitfalls? Thinking the latter but hoping not.

 

If I brought one I'd need to buy the programs and would rather pay more and get it in one piece in case I make a pigs ear of the build. I'm VERY cramped for space. There is a space it could go but said space isn't where it could be built.

Edited by Knuckles

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You do need to learn VCarve, or whichever programs you choose...... you can either use This as a basic CAD, or import a CAD file into it *Which is what I do. The primary function of the VCarve is to enable you to produce cutting paths from your drawn information. With the help of video tutorials, it is quite simple. You do need to have a fairly clear idea of what and how you want to achieve.

 

There is a lot of experimentation to find the true diameter of your cutting tools - trial and error - together with the feed rates they will put up with without breaking. So there is a learning curve, but not a desperately steep one, assuming you set about it logically and patiently.

 

If you get a setting wrong, it will break your tool, and possibly wreak your job - so it's important to get these things nailed down. Once you've got everything set up, and have learned the parameters - barring mistakes - it rather gets on with the job.....

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Hi Giles, what material is underneath the workpiece - does the mill cut into this too? I keep looking at this and other CNC threads, and am becoming more and more tempted!

 

I use Contiboard with double sided tape on my CNC mill which I suspect might be the same melamine product that Giles uses. :-)    It is remarkably accurate and I can get the work surface on it accurate to within a thou quite easily.  However,  I did read somewhere that melamine can take the edge off milling cutters so I tend to avoid cutting into it if I can.  I'm not sure if the warning is for HSS cutters and carbide cutters.  I use carbide cutters nearly all the time and I try to avoid digging into the Contiboard if I can just in case. :-)   I also use double sided tape and the few thou thickness of the tape allows the cutter to cut through the material without hitting the Contiboard.

 

I also use 12mm MDF as a spoil board where I have to use other clamping methods to hold the material,  either using clamps from the "T" slots in the table or wood screws into the MDF itself.   It works well and is almost as dimensionally accurate as the Contiboard.   It is also handy for building up supports for items which can't be clamped to a flat table and you can use the CNC mill to cut the parts for the mounts so that the edges and angles can be accurate.

 

Here's a picture of a typical flat setup clamping on MDF

 

post-542-0-26105300-1524413820.jpg

 

The part being milled was the end of a JLTRT 7mm resin coach kit and the alloy angle (B&Q) located the part and spare venetian blind strip clamped it down,  using screws into the MDF.  At this point I was checking the setup of the part before milling.

 

In the next picture,  a special mount was made from MDF

 

post-542-0-76262100-1524413575.jpg

 

This was to hold a roof for the same resin coach kit on the fourth axis so that I could mill a recess on the roof ends.  At this point I'm plotting the curve of the roof before generating a GCode file for cutting.   All the MDF parts were machined on the mill to be sure of nice, accurate angles. :-)

 

Jim.

Edited by flubrush
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Contiboard / melamine board is plastic coated chipboard. I doubt if the melamine surface is hard on tools but the chipboard is. I don't have experience of milling the stuff but it wears out steel saw blades (jigsaw and circular) in no time. On the other hand tungsten tipped circular saw blades seemed to last forever.

 

...R

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I'm sorry I missed these, Gents!

 

Although my Stepcraft doesn't often get used (there are so many other things to do!) It does get used, and does some jobs remarkably well, although not necessarily quickly.

 

I built much of the 0-14 self-propelled rail crane using the machine to mill components 

Completed crane in action 

45021378404_139bd958f9_c.jpg

2018-11-06_09-10-28 by giles favell, on Flickr

 

Showing modified bearings

44985981431_6027e7ffab_c.jpg

IMG_1109 by giles favell, on Flickr

 

The whole chassis was CNC cut, which saves trouble! 

44902833502_e30b847514_c.jpg

2018-09-27_05-15-16 by giles favell, on Flickr

 

The cab sheets were all cut with the Seocraft, together with the gearbox plates to drive between axles.

 

I have also just started another radio controlled vehicle. This one is a Morris J - a surprisingly small vehicle, which necessitates a smaller front axle than my previous models. All the axle components were profiled (very slowly) on the Stepcraft from 1mm brass using a 0.8mm dia. D bit. I used a thicker material to avoid having to have the usual round section stub axle for the flange bearings. Instead, I drew up on CAD a rectangle to fit perfectly in the 2mm dia bore of the bearing. It works very well, and streamlines the build process.

 

46637893364_66f2c558e2_c.jpg

2019-03-12_05-18-21 by giles favell, on Flickr

 

46637927814_5d6c960720_c.jpg

2019-03-12_05-22-14 by giles favell, on Flickr

 

 

 

Edited by Giles
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I've been testing the Stepcrafts abilities at things other than profiling.

 

Because I used a 0.8mm dia cutter, I was very caution about feed rates and cutting depth  - so this took over an hour!

 

40656998923_116b5571a1_h.jpg

2019-04-16_06-03-51 by giles favell, on Flickr

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I would love to hear some suggestions for speed/feed combinations for milling brass.

I have been puckering around with a similiar CNC-router, but I have never really worked out the feeds and speed combination for the different sizes of cutters.

 

I also wonder how deep cuts your machine is able to handle.

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With brass (and nickel silver) the machine itself can cut 1mm depth or more in a single pass, with a reasonable size cutter - say 2.6mm, however, with a 0.8mm D cutter, I can only reliably cut a depth of around 0.25mm per pass, and at a speed of around 0.25mm per second. More than this and I break cutters!

Brass cuts more easily than nickel silver,  but both work reliably once you find the limitations.

The other day I machined out gearbox plates from 15 thou N/S with a 1.6 cutter, single pass at about 0.6mm per second, which was a real treat compared to doing  it by hand!

I now always put a tab on the work piece to prevent the job moving on the final cut and breaking the cutter. (VCarve has a tab facility)

 

Fabricated Gearbox, with laser-cut gears

47849940971_01f4d11919_b.jpg

2019-05-14_06-19-36 by giles favell, on Flickr

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