3 Axis CNC router

**D.C.** · 04-03-2013

Just tried a different basket,

3 lots of 7.5mtr 80x40x3 = £146
1 lots of 7.5mtr 40x40x3 = £30
1 lots of 6.1mtr 60x60x6 angle = £40
1 lots of 6.1mtr 60x6 flat = £21

Total inc & delivery = £282

If you can drop down to 80x40/40x40 and redesign the diagonal bracing so that you use some flat and some equal angle for the bracing you should save a fair bit on what you thought.

**JoeHarris** · 04-03-2013

Cheers guys, really helpful. I'll have a bit of a rethink! Must cost a bit to fill with epoxy right??

**Iwant1** · 04-03-2013

Joe,

I too will be building a similar style frame to your, with lots of bolting. I think it means not only adjustment, not sure how much, but also allows me to do the welding outside then bring it in to fit together, manoeuvrability I mean. The only difference is I plan on using 90x45 extrusion just where the x rails rest. I think this is an easier method to fix profile rails onto. Not sure if it flatter, but we'll find out when the time comes, but I still do expect to file and sand till its 100% flat. Just don't want problems with the profile rails binding once everything is built.

From what I've read in the past, people use sand for filling in the hollow sections for dampening. Epoxy could be used for levelling out your 100x50mm RHS to provide a flat surface for your rails to rest on. Also could be used on the joints where you bolt the frame together like a thin shims to make sure everything ends up square and parallel. With this method you have to tighten your bolts just enough till the frame is where you want it, let the epoxy dry and harden fully, then tighten the bolts fully.

Cheers all for the heads up on types of cost involved.

Adil

**D.C.** · 05-03-2013

Originally Posted by JoeHarris

Cheers guys, really helpful. I'll have a bit of a rethink! Must cost a bit to fill with epoxy right??

If you are using west system 105, it will cost about £100 for 5kg epoxy and £50 for 1kg hardener. Depending on how hardcore you want to be with the aggergates you will end up with a mix that contains anywhere from 7% (hardcore) to 20% (lazy git) epoxy/hardener. You will also want couple of calibrated pumps for £15 - £20.

Assuming you want to fill 1m of 80x40x3 steel box internal the volume is 0.002849 metres cubed (or about 2.8 litres of space). 6kgs of epoxy/hardener is about 4.5 litres so a 10% mix would get you 16m or a 20% mix would let you fill 8m. The total cost include the aggergates (if you can buy them in small enough quantities) would be about £200.

**martin54** · 05-03-2013

Waste of money buying the pumps for something like this, couple of plastic measuring jugs from the supermarket will do the job, west systems is a 5 to 1 ratio & you would need a slow hardener. West systems is a good product but I would imagine a cheaper resin would do just as good a job for this sort of thing. Not sure about the process of filling a machine frame but generally speaking adding something like 403 or 404 fillers will aid. You can find a list of fillers & uses here. I generally use the 403 but that's more specific to work I do & not filling a machine frame.

**Jonathan** · 05-03-2013

Originally Posted by martin54

Waste of money buying the pumps for something like this, couple of plastic measuring jugs from the supermarket will do the job

I thought that...

Originally Posted by martin54

West systems is a good product but I would imagine a cheaper resin would do just as good a job for this sort of thing.

I would have thought polyester resin would be fine since it's only filling the frame.

**JoeHarris** · 05-03-2013

Originally Posted by martin54

Waste of money buying the pumps for something like this, couple of plastic measuring jugs from the supermarket will do the job, west systems is a 5 to 1 ratio & you would need a slow hardener. West systems is a good product but I would imagine a cheaper resin would do just as good a job for this sort of thing. Not sure about the process of filling a machine frame but generally speaking adding something like 403 or 404 fillers will aid. You can find a list of fillers & uses here. I generally use the 403 but that's more specific to work I do & not filling a machine frame.

Is it really necessary to start filling your frame with resin?! How much of a difference in finish are we talking for the extra expense and hassle?! My gantry will be ali extrusion in the L configuration btw... I don't want a terrible finish on my work at the end of all this but at the same time I'm not going to be machining parts for Breitling!

**D.C.** · 06-03-2013

Originally Posted by Jonathan

I would have thought polyester resin would be fine since it's only filling the frame.

Polyester isn't suitable because it shrinks too much apparently, I would refer you to the exact part of the epic thread on cnczone where that is discussed but I'm not reading that bloody thing again!

Originally Posted by JoeHarris

Is it really necessary to start filling your frame with resin?!

The whole point of being a cheapskate diy chappie is spending the least amount of money possible for the quality you want, if your machine is serving you great with steel box then it ain't broke so don't try and fix it. If you want better stiffness and vibration dampening to give better quality then it's an option open to you.

**Swarfing** · 06-03-2013

If you want to make sure all the voids are filled then try using an orbital sander against the box to work like a vibro rod. Just put a bit at a time in and vibrate the hell out of it.

**JAZZCNC** · 06-03-2013

I wouldn't bother with resin it's messy and expensive.!!. . . . . . If you need to dampen Just use kiln dried sand It's cheap and nothing works better at damping resonance.
Build in a drain hole has well a fill hole and you can easily remove when need to move machine around.