Steel frame cnc router design/build

It may be a little premature to start a build log - but I think it makes more sense to be asking questions regarding my design/build in a single thread rather than scattering questions across the forum.

I built an MDF CNC router a few years back using a design modified from the original buildyourcnc.com plans. We moved house a couple of years ago - the machine has sat unloved in (warped) pieces in the garage since.

I was planning on building a modified FLA-100 using aluminium profile - but i've already been talked out of that approach (see this thread).
I'm now instead designing a machine from scratch using 50 x 50 x 3 steel box bolted together. I'm aiming for a cutting area of 1200mm x 600mm. The machine will mainly cut MDF & wood - but plastics & aluminium are also a distinct possibility.

I have all the electronics from the previous build which include:
3x Nema 23 motors
all control boards, breakout board, 24v power supply (to be upgraded in the future) & dedicated PC at the ready.
Spindle will just be a trend router for now - another part to upgrade later.

I now plan on using supported rails from Chai/ebay.
Leadscrews are, as yet undecided.

I'd like to use 2 X-axis leadscrews - but the financial side of things may keep this as a single leadscrew for the initial build...then move to 2 as an upgrade later.

I've started drawing up a design which is far from complete. The board on the curtting surface is sized at 1200mm x 600mm for use as a guide only. In practise the lower shelf surface & full table would be covered with MDF. There's no diagonal bracing anywhere either..that can be added in later.

At the moment i'd like some feedback on the general approach & layout. I have a few minor concerns at the moment one being am I over engineering it?

I've also started wondering about bolting the frame together - there's a lot of holes to drill/tap & bolts to buy which will be time consuming & more expense....which leads to me to wonder whether its worth buying a cheap arc welding starter package (£60-75) & weld the frame instead?

Be gentle with me ;-)

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Originally Posted by CraftyGeek

I've also started wondering about bolting the frame together - there's a lot of holes to drill/tap & bolts to buy which will be time consuming & more expense....which leads to me to wonder whether its worth buying a cheap arc welding starter package (£60-75) & weld the frame instead?

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Bit busy at minute to reply properly to machine but I will later.!! . . . .This is just a BIG Yes to welder, it's not has difficult has you may think. Buy good rods and keep them dry, warm them in oven before using makes striking up much easier which is were most first time welders struggle.

You won't or don't want to be doing long continuous runs of weld just short runs and spread around to keep heat from distorting metal. Less than 1hrs practice on some scrap and you'll have it sussed good enough to do what you want.!!

i thought you might say that...is a cheap Arc welder up to the job in hand though? Anything I need to be aware of? (sorry I have absolutely zero knowledge of welding)

I'll need to rework the machine assembly to allow for welding rather than bolt together...it'll be cleaner layout.

yeah, get a cheap machine, it will be fine

beauty of arc welding, is its EASY especially if your welding 2mm+ mild steel. even easier with new steel

get 6013 rods. say about 3.2mm (which again are good allrounders)

Thanks kingcreaky - i've spotted a Ferm 100A unit on ebay that comes with basic accessories that looks like it should be enough to get me started.
Regarding the rods - what does the 6013 bit mean?

I've done a quick reworking on the design so far for welded assembly - it currently has a bottom on the gantry for a single leadscrew, not sure if this is staying yet or not (probably not).
As mentioned before, i'm interested in comments about the approach as a whole - not anything too specific yet as i've still got quite a bit to do on it.

a 6013 is just a type of welding rod. Reading into it before posting this it appears 6013 seems about the most common type used but here is the speal if your interested

Different Types of AC Welding Rods | eHow

no doubt this clever lot on here will tell you these are the wrong ones... but they are the ones ive always used. Work perfectly fine all weather for me

regarding your design...

Good start... ive seen a lot worse.. but in my opinion...

*id have a center leg on each side rather than use the bed horizontal as brace (you could use that aswell)
*more bed frame crossmembers
*forget the single ballscrew arrangement for the X, use two one on either side
*triangulate the corners wherever possible
*If you think its over-engineered at any point... its not.. you watch it dance round the workshop like its made out of carboard when its cutting. You wont regret stregth in design

read ALL the other build logs...

My machine

http://www.mycncuk.com/forums/router...ation-cnc.html

is similar to your design

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Originally Posted by CraftyGeek

Thanks kingcreaky - i've spotted a Ferm 100A unit on ebay that comes with basic accessories that looks like it should be enough to get me started.

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No Don't buy 100A welder you need more Amp's spare for duty cycle. Biggest problem with cheap Arc welders is low Duty cycle or better put the time you can weld before the it trips out from over heating is short.!!
Now your not going to be running long welds or in a rush so it wouldn't probably be a major problem but for £10-20 more you could get 140-160A and have decent duty cycle with less stress on welder.

Like Matt says 6013 rods but more important is ONLY buy decent quality IE: branded name BOC, MUREX etc none of this rubbish you see at Aldi or car boot sale etc and keep very dry.

Regards 6013 it's the AWS standard (American Welding society). Rods usually have prefix like E-6013 and it breaks down like this.!!
E= Suitable for MMA welding and flux coated
60= Minimum tensile strength in KSI(Kilo-pounds(force) square inch) IE 60Ksi = 60,000psi pounds(force) per square inch.
1= Suitability for welding positions . . . IE: 1= All positions 2= flat & horizontal positions
3= Flux coating type and suitable Current types IE: 3= High titania potassium (Rutile) AC or DC+ current.

See here for a good Arc tutorial and loads of info.
Arc Welding Tutorial

I'll look at frame and come back to ya.!!. . . . Get ya hard hat on ready. . .Lol

Ok I'm back with my wrecking ball . . Get ready.!!. . :hysterical:

So I see you've been paying attention with using the high sides and gantry sat on rails design which is great for twin screw machines but in this case it's actually hurting your design badly.?

Because your wanting to use single screw (with option to upgrade) this means having gantry cross brace but with those high sides it means having long gantry sides which are acting has levers. They will flex, twist and stress the bearings, they will also resonate like crazy, this all transfers back to the work or like Matt hinted at make the bloody thing dance around the room if bad.!!. . . Not good design for this way of doing it.!

Really because of your budget restrictions then your going to have accept a bit of compromise on design.? In this case it's flexibility regards cutting height and materials you'll be able to cut. The high sides with gantry on rail design works very well if you want strong rigidity and flexibility of lifting the bed but it just don't work for use with single screw.

So your going to need a way to keep Gantry sides short has possible but yet high enough to give clearance you'll need for cutting what you want to cut.? . . . . It's simple enough you can't have high clearance and high strength,it's always a compromise with this way of doing it.
So best thing is first decide the lowest clearance you can work with a build frame that allows gantry to be kept short and strong.!

There's several ways to build frame to allow this and I'm not going to try telling them all I'm just going to show the sort of thing I'd build for this Budget and upgrade has you can afford way of doing things. (It's just something I knocked up to show principle not finished design)

This gantry/frame design will be very strong and use's roughly 2.5 x 7.5mtr lengths of 80x40x3. It can easily be converted to twin ballscrews.
It's shown has desktop machine to keep cost's down but making it free standing would be simple enough just cost more.

Hope this helps and carry on it's perfectly do-able to build strong machine even on budget.

Oh one more thing or Tip with modelling.? . . Get accurate dimensions or better still Cad models for the things you plan to use, like ballscrews, motors etc has it's easy to think I'll use this or that like this and then it doesn't fit or interferers with something else.

Thanks Jazz.
I have made a few changes since I posted that last image...the main one being the removal of the single leadscrew option. I've decided that I want to do a decent job of this, which means it'll take me longer to get it running - but the end result will be worth it...so dual leadscrews from the start - hopefully driven from a single motor.

I'm still very much tinkering with the overall dimensions - I have shrunk the z depth & reduced the overall height a bit as well.
I hope to have a bit more time to spend on it tomorrow to make some more changes, then i'll come back for another slap on the back of the head :-)

On the gantry you posted above - I assume that the spindle mounts between the *ahem* open legs?
Question...does the distance fore/aft that the spindle is mounted (relating to the x rail bearings) have any effect other than allowing the cutter to reach different areas of the table?

I can recommend the Clarke Easi arc welders from machine mart... Mine has been great so far. Also just got an evolution rage 2 cut off saw for slicing up all the steel - again it's awesome but chucks little bits of swarf everywhere! Good luck with it - you're in good hands with Jazz he tells it how it is!!

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Originally Posted by JoeHarris

I can recommend the Clarke Easi arc welders from machine mart... Mine has been great so far. Also just got an evolution rage 2 cut off saw for slicing up all the steel - again it's awesome but chucks little bits of swarf everywhere! Good luck with it - you're in good hands with Jazz he tells it how it is!!

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I'm currently eyeing up a Ferm 160Amp job at the moment - looks like it should do the job nicely.

I got an Evolution Rage 3 last year...love it - it won't stop for anything!
Despite hooking it up to a decent dust/chip extractor it still chucks out crud everywhere :-p

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Originally Posted by CraftyGeek

On the gantry you posted above - I assume that the spindle mounts between the *ahem* open legs?

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Yes just slapped some bearing and front Z plate on to show see pic.

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Originally Posted by CraftyGeek

Question...does the distance fore/aft that the spindle is mounted (relating to the x rail bearings) have any effect other than allowing the cutter to reach different areas of the table?

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Some would throw math's and moments of inertia etc shit like that at ya but in reality it's nothing to worry about really, so long has your not daft about it.
I just try to keep the overall weight balanced on the X bearings. Mostly It's just balancing act between losing or gaining cutting area.

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Originally Posted by JAZZCNC

See here for a good Arc tutorial and loads of info.
Arc Welding Tutoriall

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Had time to have a quick look at that page this morning - that's a fantastic resource, Thanks!

I'm looking for more local sources for materials. I have a good local steel yard 5 miles up the road that i've used several times before - so am happy to use them for the framework, but their aluminium stock is low, a bit battered & unreliable.

I've found that there's a branch of Blackburns Metals not too far from where I work - does anyone have any experience with them as a supplier for aluminium?...quality & prices ok?

No experience with Blackburns but if you haven't got a milling machine to surface standard plate then who ever you use I recommend you buy ground flat plate for key areas like Z axis and bearing plates. . . . It's more money but worth the expense because standard plate is never flat, it may look flat but it's not.!! So for critical areas like Z axis and bearing plates where surfaces must be flat and parallel to each other they must be surfaced flat.
I have the capability to surface plate and still I buy ground plate for these areas has it saves me hassle and time and even careful milling can't match ground surface quality.

Even Round rail which is very tolerant of bearing/rail miss alignment will bind and stick if plate is slightly cupped, less than 1mm cup, bow or twist over 300mm bearing plate length will be enough to totally lock the bearings when fastened to plate. Normal rolled plate can have that much error and I've seen plenty folks fall foul of this and corrected several bearing plates for people because of this.

If you can't get it from Blackburns then I suggest aluminium ware house because they cut to size and you can order just slightly larger than you need for those areas. Your Looking for ECOCAST at AW it's here. Aluminium Plate - Cut to Order - Aluminium Supplier | Aluminium Stock | Aluminium Warehouse

PS: For rest of plates like motor mounts and even gantry sides etc then normal plate is fine, if you have decent metal scrap yard near by it's worth checking them out has often they have offcuts etc from industry and some can be large and quality, most just charge scrap value.

Thanks Dean,

At the moment I was thinking more for the less important parts - motor mounts etc as it will make life a lot easier having a reliable local source that I can nip into to get the occasional piece without any postage costs.

I've seen AW mentioned in several build logs & have them bookmarked already when it comes to the important parts. It seems the narrowest width for the Ecocast is 100mm which may well make a design decision or 2 for me as well...although this could be an issue when it comes to mounting the Y rails on top/bottom of the gantry?

I assume that 5mm Ecocast will be ok for the rails to mount to?

I think steel is an excellent idea, so is a stick welder, but I would still like to take this opportunity to screw up your whole design at the last moment because that is what I do best :pride:
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When a weld cools it solidifies then shrinks. The shrinking bends everything out of shape with no possibility of correcting it. If you are a novice welder your welds are unlikely to be drop dead gorgeous and the effect is amplified.
.
Meaning you end up with a framework that is wildly out of square, it fills half the workshop, is tricky to get it out the door and take it up the dump.
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If you are fiendishly clever you can try to pull everything square by welding in cross braces after the event and hold the thing in tension.
.
If however you plan ahead and weld plates bearing bolt holes to your bars you have a chance to straighten things up after everything has cooled down. A round file can move a bolt hole, an angle grinder can square up a face, packing can be tack welded in place.

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Originally Posted by Robin Hewitt

If however you plan ahead and weld plates bearing bolt holes to your bars you have a chance to straighten things up after everything has cooled down.

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Hi Robin - could you elaborate on this bit a little...I'm not fully sure what you mean.

I'll be taking it slowly, small tacks to pin it together first - check it all, then go round again.

Easy to find out for yourself. Saw a piece of box section in half, weld it back together, see how straight it is.

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Originally Posted by Robin Hewitt

I think steel is an excellent idea, so is a stick welder, but I would still like to take this opportunity to screw up your whole design at the last moment because that is what I do best :pride:
.
When a weld cools it solidifies then shrinks. The shrinking bends everything out of shape with no possibility of correcting it. If you are a novice welder your welds are unlikely to be drop dead gorgeous and the effect is amplified.
.
Meaning you end up with a framework that is wildly out of square, it fills half the workshop, is tricky to get it out the door and take it up the dump.
.
If you are fiendishly clever you can try to pull everything square by welding in cross braces after the event and hold the thing in tension.
.
If however you plan ahead and weld plates bearing bolt holes to your bars you have a chance to straighten things up after everything has cooled down. A round file can move a bolt hole, an angle grinder can square up a face, packing can be tack welded in place.

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Don't listen to him he's just like to blow the froth of peoples coffee . . .:hysterical:

He's partly correct about heat and cooling, shrinking but if done correctly like I said short welds spread around it can be minimised enough to be fine. The wildly out of square comment just means he's been doing it wrong. .:whistle:

The squareness of the frame isn't critical, yes it's got to be close but 1-3mm or so out won't hurt.! And if welded has mentioned it won't warp or twist anywhere near that amount.

It's the rails that matter and these MUST be square and parallel to each other and on the same plane.
To help your self with this on the Long axis, which I call X it pays not to weld the top rail but bolt it to flat plates. If there's any error then you can shim into plane and move parallel and square to each other very easily.

Then there are other little tricks for dealing with things like the top plates rails sit on arn't flat etc. Putting Epoxy putty between rail and plate creates a lovely surface and give enough time shim square etc and then when dry you have perfect surface and it's also helps dampen resonance.!!. . . . There I've give one of my tricks away. . Dam.:distress:

I do this all the time so believe me it's not difficult so don't let comments like "Victor" Robin "Meldrew" put you off welding because it's by far the Cheapest and strongest way to build a machine.

Edit: Better elaborate on the Epoxy comment.!! . . . You must put piece of cling film or thin plastic between top rail and putty other wise you'll stick the buggers together and never get them off. .:stupid: . . . .Oh and it's not expensive. 125g packs for £2 and it goes fair way has your only spreading thin, 2-3 tubes will do full machine.

I understand that bit - its the 'weld plates bearing bolt holes to your bars you have a chance to straighten things up' bit that i'm not clear on the meaning of...

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Originally Posted by JAZZCNC

To help your self with this on the Long axis, which I call X it pays not to weld the top rail but bolt it to flat plates. If there's any error then you can shim into plane and move parallel and square to each other very easily.

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Like that....pinched ;-)

Anyway back on track.!!

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Originally Posted by CraftyGeek

I assume that 5mm Ecocast will be ok for the rails to mount to?

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Because using supported round rail then I wouldn't bother with Ecocast has the rail base will have more error than the steel. You only really needed plates between when fastening to Ali extrusion. If that's your plane then just buy normal Ali about 10mm.

If your meaning 5mm plate to sit on bearings then NO you'll need absolute minimum 10mm, 15-20mm is the norm.

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Originally Posted by JAZZCNC

Edit: Better elaborate on the Epoxy comment.!! . . . You must put piece of cling film or thin plastic between top rail and putty other wise you'll stick the buggers together and never get them off. .:stupid: . . . .Oh and it's not expensive. 125g packs for £2 and it goes fair way has your only spreading thin, 2-3 tubes will do full machine.

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Try sellotape or brown packing take next time. It self releases.

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Originally Posted by r0bsk1

Try sellotape or brown packing take next time. It self releases.

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Yep good idea, I just normally use plastic sheet because I generate shit loads of it at work and it's free. .:applouse: . . .. Well not free suppose because I've paid for it when bought the bloody stuff it was covering. .:highly_amused:

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Originally Posted by JAZZCNC

Edit: Better elaborate on the Epoxy comment.!! . . . You must put piece of cling film or thin plastic between top rail and putty other wise you'll stick the buggers together and never get them off. .:stupid: . . . .Oh and it's not expensive. 125g packs for £2 and it goes fair way has your only spreading thin, 2-3 tubes will do full machine.

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Is this a thick fast cure resin, medium/slow cure with additive/filler or some sort of putty that i've not come across before?

In other news - i've ordered a 160A Arc welder via an auction on ebay...will need to pay a visit to my steel yard shortly to get some scrap to practice on.
The steel yard also sells welding rod - i'm assuming that because they do fabrication themselves they'll be decent rods...they do a box of ~250 6013 3.2mm for about £28+VAT - does that sound ok?

I recommend this archaic video if you are learning to stick weld...
www.youtube.com/watch?v=zWdgEaXWDxQ

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Originally Posted by JAZZCNC

The wildly out of square comment just means he's been doing it wrong. .:whistle:

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Jazz will now tell us how far out of square is acceptable and I will stand by to say "Told ya so!" when it all goes tits up :victorious:

You will require an angle grinder.

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Originally Posted by Robin Hewitt

You will require an angle grinder.

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I've already got one with a supply of thick & thin discs ;-)

You may be interested in my steel frame router Home Built GantryMill Improvements - YouTube the cutting area is 600mm x axis and 350mm y and 100mm z. It is built with materials I had to hand hence the mixture of steel and aluminum.

I would like to echo Robins comments about distortion caused by welding, it can be a nightmare so you will need to be very careful, also it is easier to weld thicker material but harder to remove the distortion.

Home

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Originally Posted by JoeHarris

I recommend this archaic video if you are learning to stick weld...
MMA welding (welding institute) video guide - YouTube

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That's a great video - just watched it all the way through...i'll probably watch it again before having a go myself.

Only trouble is how easy "max" makes it look to get a perfect weld!! I was more than a little disappointed with my first couple of attempts!

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Originally Posted by Robin Hewitt

Jazz will now tell us how far out of square is acceptable and I will stand by to say "Told ya so!" when it all goes tits up :victorious:

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If you look again you'll see I mention 1-3mm.!!. . . Now let me ask you this Robin.! . . How many Steel framed routers have you built.?

I'll say it again just to be clear.!!. . So long has the welds are kept Short 1"-2" Max and Don't weld in one spot moving around the frame you'll be fine. Even just welding several short bursts and having a break to prevent heat form travelling if your unsure will help. . . . Remember it's DIY so there's no Rush it doesn't have to be done in same day.!

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Originally Posted by CraftyGeek

Is this a thick fast cure resin, medium/slow cure with additive/filler or some sort of putty that i've not come across before?

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It's a 2 part putty paste called Milliput, see here Milliput - The epoxy putty with a thousand uses in modelling, DIY and industry
Comes in sausage shaped cellophane wrappers. Easy to use just mix equal parts in your fingers just like mixing Play-doh. Then spread on Clean dry surface and sets like concrete in about 6-8hrs, packet says 3-4 but I've found it's longer and leave over night. Leaves a super flat surface it can be tapped, filled and ground just like steel.


Here's Where and how I use it. It's also why steel or frame distorting slightly is no big deal.!!

Most of the frames I build are a mix of welded and bolted like these pics below. ( Frame only here no Bed, it's adjustable) At the joints and where top rail sits on plates is where it's used.
When I'm all finished and welding up then I bolt frame together to get an idea of how far off things are.? Most the time they are hardly off at all and just a quick grind or tweak of mounting plates brings it near enough to call Ok.!! . . . Some times shims may be needed.
Remember the rails being parallel and on same plane are the important areas and because the top rail is Bolted we have complete control and adjustment of this. It also doesn't get welded so NO distortion happens, just choose the straightest unbent piece you can find. (We have ways around bent rails has well but won't get into that now.)

Now in most cases after shimming or grinding true and square I could leave it at this but I don't. I go one further and disassemble again this time rebuilding with Epoxy putty at each joint with cellophane between to prevent sticking together.
This gives me about 1hr to set the frame square and true, Doesn't matter if the welded frame isn't quite square or plates not perfectly flat etc because the putty is going to take up any slack. . . . . So long has the shims from first assemble are used then All that matters is that frame is SET square and uprights vertical Now because Putty's going to fill any discrepancy and when it's set solid over night you have perfectly flat and true surfaces. The shims can be removed or set left into Epoxy.
Now where not talking 5 -10mm thick epoxy pads here, there often just wafer thin just filling voids etc.
Drilling and pinning the joints with dowel pins helps make sure everything goes back in same place and makes assembly easier.

Again the main frame being 100% perfectly square isn't overly important, it's the top rails that matter.!! . . Can't stress this enough.

Now what can be more of a pain to deal with is Twist of welded sections from distortion but again depending on design etc this can be got round. Often it's just a case of forcing the twist out by twisting in opposite direction, if twist is happening then you can often see it has your welding so stop and twist it back. This is also why spreading the welds around is important.
The bed is the main area you need to keep an eye on distortion and even then again Epoxy can be your friend if really bad and with a bit of Brute force and epoxy if need be then the Bed can easily be sorted to within a knats cock. When spoil board is surfaced then it will be Cock On.!!

Now here's what the scare mongers, who probably have never built a steel framed machine are not saying.? . . . If at first you don't succeed just grind the bastard apart and re-weld or re-set that's one of the beauty's of steel is it's flexibility for having another crack at it.

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Originally Posted by JAZZCNC

Now let me ask you this Robin.! . . How many Steel framed routers have you built.?

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Like this? None. Every router I have made has been job specific :topsy_turvy:

Ok - design progress time.

I've been focusing on the frame/table so far - its now at a stage where i'm pretty happy with it & I think i've added everything that I meant to.

red = 60x60x4 box
blue = 50x50x3 box
green = 60x4 flat bar
orange = 50x4 flat bar

Rails are sat on 50x10 ally flat.

Ignore the floating guide leadscrew for now - its just there as a vague reference as to where i'm planning to put the leadscrews at the moment. Also ignore the holes going through the outside of the legs, they won't be there when I make it.

The frame has the ability to be adjusted for square in every direction. The cutting surface can be positioned in 5cm increments down the legs.
Both the lower surface & cutting surface will be covered in mdf added further bracing.

Hopefully this will mostly get nods of approval :uncomfortableness: so i can move on & start thinking about leadscrews, motor mounting & the gantry in more detail.

Ok looking much better.!! . . . Take it you have decided not to weld.? If so Not saying this is bad thing if that's what your most comfortable with but will be a lot more work and maintenance. Mixture of both works best IME.

Only thing I see and question is DO YOU really need that much adjustabilty of the bed.? If not then I'd raise the lower frame and increase the triangulation. Will just help stiffen the frame a little.

Crack on.!!

There are still welds in there - I think I need to see how I get on with the welding to see how accurate I am with it...then if I feel confident enough, i'll drop more of the bolts & weld instead (like the table surface). I do want to make it so that the whole frame can come apart into manageable sections for moving house etc in the future.

Regarding the height adjustment - I don't know is the short answer...I've seen that others do it & it might be useful for me at some stage - but I don't have any examples in mind. In reality I probably don't need that much. I'm also still playing with the overall dimensions a little - so i'll still be tweaking for a while.
The frame at the moment should be a decent height for me to work at - i'm conscious of making it too low & giving myself back issues (which I get from time to time)...more cross bracing can be added at a later date easily enough.

[QUOTE
Most of the frames I build are a mix of welded and bolted like these pics below. ( Frame only here no Bed, it's adjustable) [/QUOTE]

Jazz, do you mind explaining how the bed adjustment holes work on the frame pictured. It looks like you have another tapped plate or something inside the RHS? Cheers
joe

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Originally Posted by JoeHarris

Jazz, do you mind explaining how the bed adjustment holes work on the frame pictured. It looks like you have another tapped plate or something inside the RHS? Cheers
joe

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Yes there's a 10mm thick plate with holes tapped it.The holes in legs are drilled oversize for clearance. The 10mm plate is tacked in place to hold.

The main bed frame is heavy so there's 4 lead screws (2 each side) to help lift up and down and roughly get into position. Then there's 8 angle plates(4 each side) fastened to bed frame with 2 holes in each so 16 Bolts total that bolt into uprights with 10mm tapped plates inside.
It's simple and easy thou to be honest it's not something you do very often has usually you'll settle on a position that allows 90% of what you want to do.!. . . . It's just nice having the flexibility to do oversize things when needed.

Chaps - i'm dithering about with the gantry quite a bit...can't come up with an approach that i'm happy with yet.

I've been looking around at a lot of build threads on here & cnczone...I haven't seen a gantry design that seems to suit what i'm doing.

Firstly - do I need to be concerned about weight. ie, am I ok using steel box or is this something that I may regret later?

Secondly - Jazz, the mock up design that you posted earlier in this thread - the gantry on that has 2 lengths of steel box attaching to vertical end pieces. I assume this would have to be a weld - my concern here is alignment & the lack of adjustment. Is there another way of going about it?

I'm trying to keep the range of materials that need to be purchased down...i've been looking at using aluminium box with a vertical plate - but it starts upping the budget quite quickly.

I'll also drop in a note here that I also really like the simplicity of KingCreaky's gantry...cheaper than some options, but the ally rect box & front plate add up quite quickly.

Any thoughts?