Testing Four Engraving Bits / CNC V Carving

So I was sent some bits from a company called RouterCutter.co.uk – which as of December 2016 / January 2017 is a relatively new company. They supply CNC router bits here in the UK and Europe stocking American and Italian made cutters.

They have supplied me with four Whiteside carbide engravers which I would like to learn how to use – and I’ll be doing this on my original belt driver CNC machines as I’m still working on the controller for the lead-screw machine.

So the bits I’ve received are as followed

22º Carving Liner which is model number SC50

30º Engraving Pencil Point, model number SC70

Point Cutting Round-over Bit, model number SC1568

15º Engraving Bit with a Flat Point, SC54

So what do these bits do? When it comes to engraving I’ve only ever used 60 and 90 degree carbide tipped v-carving bits – the sort you get with a hand router, which I’ve used to do some engraving such as the Guernica drawing.

The material was a little bowed or maybe my waste-board was not entirely levelled so you can see the lines are a little thicker to one side.

I suspect I can do intricate and smaller engravings using the more acute angles of the 22 degree carving liner and 30 degree Pencil Point. But I’ve not used anything like the Point Cutting Round-Over bit or the 15 degree flat point Engraver- so I am curious to see their effects.

Anyway before I start I need to input the various tools details into my software’s tool-database. I’m going to try some simple lettering on a scrap piece of red Valchromat – from Gcode created in ArtCam Express 2015. I used the carving liner and pencil point, but quickly noticed I could not control the feed-rate.

CNC is never straight forward… when I’ve prepared files in the past I normally export the vectors as SVG files, and cut them in Easel where I set the feed-rate. This time I was running G-code directly through Easel and the federate was maxed out – only limited by the maximum allowable feed-rate in the GRBL firmware itself.  What that means is – the gcode was set to 30,000 mm a minute in the file I exported, but was limited to 3000 mm a minute, which is still way too fast.

Anyway if you’re wondering why I’ve written “What you doing Savva?” I haven’t got YouTube fever – have a listen to this voice message from by niece. What you doing Savva? What you doing Savva? Wait for it. What you doing Savva!

So back to the video, I’m applying the various tools to the lettering to see how paths manifest. The lower angle of the 22 degree carving liner means it needs more passes to router a deeper channel than compared to the 30 degree pencil point.

For some reason the software wouldn’t let me carve lettering using the round over bit. That tool is sideline for beading work for now, unless I fool the tool-database into thinking it’s something else.

The other thing I noticed was the flat point of the SC54 engraver made it almost impossible to use when doing smaller carving. That bit lends itself to block lettering like that used on a printing press. Carving from the outside of vectors could be useful to make stamps or printing blocks, and the 15 degree bevel it leaves would also make a good releasable surface to take moulds from or do vacuum forming.

 

I’m just highlighting the areas which will be rough cleared with a ¼ inch bit and the detailed work of the flat point engraver.

The first thing I have to do however, is work out how to control the feed-rate – otherwise I might break a bit and will not get the best finish on the material I’ll be working on. I suspect I will have to edit this information manually in a text document. There are some different standards to g-code and I think a few programmes such as v-carve and fusion 360 have a post editors which prepares the Gcode for the machine you will be cutting it on – in my case a GRBL machine.

Annoyingly ArtCam Express doesn’t have a plug-in for GRBL and there seems to be very little support for the older versions of their software – especially since they have gone with an expensive subscription only software.

Using the copy and paste tool in wordpad I have changed the federate to 600 mm a second, and the plunge rate to 150 mm a second. This should help make for a cleaner cut.

So what I’m going to do now is export some G-codes and cut something for each of these four bits and show you the outcomes.

Here I’ve used the carving liner to engrave some small lettering – it work well on text up to 4mm tall, or when limiting the tool depth to 1mm.

Because of the 22 degree angle above a certain size of letter the bit plunges a little too deep and the lettering looks a bit odd. I also had some problem with parts of the lettering chipping but that is a combination of my feed-rate and the material I am cutting.

The pencil point has a slightly larger angle which means engraving letters looks a lot better and this works a little larger than the carving liners. That said limiting the tool depth can produce a better finish when cutting smaller lettering.

As I mention before I couldn’t cut lettering out using the round over bit so I cut a simple border which could be used to frame engravings – and this also looks quite good on the denser Valchromat.

The last bit was a flat bottom engraver with a 15 degree bevel. Because of the flat bottom or tip, the tool wouldn’t be able to reach the crevasses of smaller lettering and engravings. So it decided to cut some block lettering instead. I used a roughing tool path with a ¼ inch bit to make the job a little quicker, cutting from the outside of the vectors and finishing with the flat bottom engraver.

This was by far the most interesting effect when producing lettering.

So to conclude, how I imagine using these bits. I think I’ll use the carving liner to do smaller detailed works but in particular drawings. The pencil point will work better doing lettering as the angle suites it-self better to that task. I’ll use the round over bit to do beading and boarders, and the flat point engraver to make larger block lettering.

Thanks again to Routercutter.co.uk for supplying these to me – there details will be in the description bellow.

I’ll also add if you want to v-carving yourself you don’t have to get expensive software, you could use something like ScorchWorks F- Engrave and I’ll provide a link to that as well in the description.

 

 

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