Member postings for RobC

I believe that Martin has the answer - you need to define a start position.

So any of these should solve it:

1. Set a machine zero position
2. Set a work zero position / offset as Jan suggests
3. Add a 'move to 0,0,0' command into the gcode before the arc (G1 X0 Y0 Z0)

For 1 & 2 I think you can do these in the UGS interrface using the 'reset zero' command or the 'reset' buttons next to the X, Y, Z indicators.

Are you able to use the JOG functions in UGS to move your machine?

Have you set your zero positions (X,Y,Z) somewhere in the middle of your machine bed. Just so that it is possible for it to move around as requested?

OK, I also use UGS and have just plugged that code into my machine - it runs perfectly!

So, I believe that your issue is one of configuration, frustratingly.

The Universal Gcode Sender software is happy with the upper/lower case lettering, the spaces, the preceding zeros. and the decimal places. So there's no need to worry about them.

Hi Gary,

This code is generating an error describes as:

The motion command has an invalid target. G2, G3, and G38.2 generates this error, if the arc is impossible to generate or if the probe target is the current position.

This means that your gcode doesn't make sense to the controller software.

If you examine the gcode, you can see the problem. (I don't know where it came from, but it isn't really a helpful piece as a sample program).

If you take a look at this link you can see how a counterclockwise arc (G3) is defined in gcode.

G3 X0 Y0 I20 J0

The command to move in an arc needs a start point, end point and centre point.

The code in this line describes the end point and the centre point, but requires a start point to be identified before it can move.

G3 - Start counter clockwise motion

X0 Y0 - the end point

I20 J0 - centre point of arc (relative to start point)

You can probably see from this description that the start point is required. I would normally expect to see a line like this in front of the G3 command line:

G1 X0 Y0

This would set the start point at (0,0) and allow the second line to describe an arc between (0,0) and (0,0) centred at (20,0) - This describes a circle with radius 20.

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Sample code it always tricky, particularly from an unverified source. A CNC machine is very unforgiving when things go wrong. They try to do exactly what they are told, with little or no reality checking along the way.

They are fantastic fun, but have a pretty steep learning curve in the early stages.

I hope this helps...

Rob

The only thing you really need to look at is the duty cycle of the grinder. Many are not rated for the sort of long use that some polishing entails. Mine needs a half hour break every 30mins to stop overheating too much (it becomes a little too toasty at that time)!

I had mine from one of the suppliers linked above and it works well, but what you get is a simple grinder (complete with grinding stones) which you then disassemble to fit your pigtails to. With some searching you can probably find a less expensive one elsewhere (350W is a good starting size).

Be careful where you site the grinder as it also has a tendency to grab things from your hand and throw them about with some force.

The polishing mops also fling fluff around for the first few hours too.

I usually start most ideas with pencil and paper, as there are lots of constraints that are too fluid for a formal drawing.

Once the idea is fleshed out a bit more, I may use SketchUp for simple shaped 3D designs, or Autodesk Fusion360 for those needing more definition and control.

I usually finalise things using Draftsight, as it is my 2D drawing package of choice.

The best part of all of these choices is that they are all free, which is the right price for me!

Hi Nathan,

There's a great and helpful group over on the Practical Machinist forum, specifically for Deckel machines. Lots of guys who know these machines inside out on there. who may be able to help out.

Also you can find lots of Deckel bits from Franz Singer either on their direct web page or their eBay store. They are German, but speak excellent English and you can use the translations to work out what most things are very easily.

Good luck,

Rob

Oops, looks like this forum uses a slightly different method of linking than the others I am used to.

**LINK**

The P.P. Thornton website was 'updated' over the weekend, so has been a little intermittent for some. I spoke to them yesterday and they are very pleased with the new site, but a little disappointed that it was not as instant an update as they imagined.

The revised site is much more 'consumer friendly' and allows you to see examples of their cutters, along with prices for the different variants.

I found a replacement from another scrap vice in the end, Tim

One way to do it is to connect a 'braking resistor' to the drive which, when the VFD is configured to know it is there, will help it slow down faster. The manual will (usually) have a list of suitable sized resistors in it somewhere, along with the settings you need to change.

The braking resistors are typically low resistance, high wattage, ceramic units (mine took a 100ohm 300W resistor).

Oops - wrong subject!

Edited By RobC on 26/05/2015 13:17:01

All the Fobco Drills have worked with had BSF threads on them, which was very handy, as I have a good set of taps/dies for them. There will usually be an oddball thread among them, probably where something has been replaced.

It may be worth trying a coat of shellac. It can work as a good intermediate finish, binds to just about anything and most finishes will bind to it too. It is often sold as 'sanding sealer'.

Oops! It looks like JS beat me to it with this one...

I'm not sure how interesting it might be to folks here, but this morning I received notification that Quinetic are auctioning off some model ships.

The collection of ships offered for auction are all commissioned custom hand built to a 1/50th scale from copper by craftsman (Pre DERA) in the late 1970’s to the mid 1980’s, their purpose was not for display but for the signature data collection specific to the ship that they represent.

They are all manufactured from soldered copper, and have hollow flat drop bottom hulls.

Further details are to be found here:

http://www.ppauctions.com/eshots/20141128/

Late on the wagon here, but no rush from my perspective.

PM sent

Thanks, Rob

I have restored three Fobco drills over the last few years, usually buying them at auction for a low price. I have never sold any on, but my brother's both now have very snazzy looking drills! They are extremely robust and spares are available for most of the major elements; although things like a replacement table can be pricey!

They are fabulous machines and very sturdy. I'm not sure I would try to do any milling with one, but if you can find a model with the MT2 socket, it would hold an interesting variety of things. Personally, I have not seen any of them when looking at the benchtop models. I never had room for a floor standing model, but you may find one of them with it.

The best place to find them is commercial auctions (NOT eBay) as they are generally found in older engineering businesses. They are built to last and can suffer a huge amount of abuse before failing. Swapping out a 3phase motor is also easy, there are suppliers for identical flange mounted single phase motors out there.

Will,

This possibly isn't much help, but I have recently obtained an 800W air cooled Chinese spindle and VFD. I am using it on my home-made CNC gantry mill (CNC router from aluminium frame sections).

I have successfully cut wood, plastic and aluminium and have been impressed with the spindle and controller. The setup is 'interesting' as most of the VFD information is a bit sketchy, not due to omission, but rather to ambiguity! Having worked that part out, I am happy with the finished article and am slowly incorporating the electronics into my system control.

The only modification I did make to the spindle was to earth the casing, which I thought was a sensible precaution with the voltages being used.

The package of spindle and VFD came in at just over £200, which I thought was reasonable. I opted for one of the suppliers that holds stock in one of the UK ports and 'imports' it on demand, rather than wait for it to arrive from China.

I have only been using it for 40-50 hours so far, but it has performed faultlessly so far.

Rob