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Yep, otherwise it wont even mix properly.Quote:
Originally Posted by Clive S
Before SP:-
https://www.youtube.com/watch?v=2IeEhFW44F8
After SP:-
https://www.youtube.com/watch?v=4KfWcawy7b4
I used too much SP but it worked well. I dont know the make I used, got it from my 'pimp' in Germany but its higher end stuff (at least, that is what he said).
Thanks Yes I have seen them. I am a bit surprised about the amount of cement in the mix it seems massive to me and what I have researched. You can the get SP in the UK though.
Was you're SP powder or liquid? and what quantity to the cement?
Looking forward to see the next bit done.
Yep, aware that SP is locally available too. In this case I am taking guidance from the person that supplied me with the rails and ballscrews. He works in a facility where they test lubrication and also very experienced across various machine designs. His own personal machines consist of items where they are temperature controlled etc otherwise the machine 'goes out of tolerance'.Quote:
Originally Posted by Clive S
In this case the SP was liquid. Ive seen utoob vids where powder is used. As if my 'magic' the dry mix becomes liquid. Amazing stuff this. I used 50ml / kg of cement although I believe 25ml would have been acceptable too. So 1.25litres per 25kg of cement (or one mix for me in my mixer).
Have had further progress, will upload pics later. Putty cast, rails mounted with nuts epoxied in. Started to clean up the parts needed to mount the ballscrew. Hope to have this sorted by this weekend and potentially motor movement on the Y axis this weekend or next latest.
Hi Chaz
nice hear of your progress, can you give a detailed run through on the rail fixing process, am curios as to how this is done.
Regards
Mike
Will do. There is a run down earlier in this thread. Ill take pics and explain the process. Some of which I think I can improve in future but at least I have a flat surface I can work with.Quote:
Originally Posted by mekanik
Putty done, levels look good. I am using a surface plate upside down as a table but also to get alignment of the ballscrew / mounts before I putty the level for the bearing holder.
https://c1.staticflickr.com/9/8342/2...3f97d631_b.jpg
https://c1.staticflickr.com/9/8798/2...ffab71ca_b.jpg
I am having some issues with the epoxy I ordered and its delaying my build.
Can anyone recommend an epoxy which is suitable to do hold things like nuts in place for where the rails get mounted etc?
Thanks
Hi Chaz
This any good?
http://www.ebay.co.uk/itm/ANCHORSET-...8AAOSwq7JUGAUU
Mike
Thanks. Not sure.... anyone have experience of this? Google brings up loads of products however I dont want to pay school fees if someone knows what might work from previous experience. That said, £6.63 is worth a punt to try.Quote:
Originally Posted by mekanik
I believe this should work. Sika are well regarded as far as I understand.
http://www.uksealants.co.uk/sika-anchorfix-1--p84.html
Chaz I have used both of those in the past with great success. You will need to prepare all the hole first and blow any dust out. The nozzles on the tube are a duel flow type and in my experience cannot be used more than once so try and do the job at one sitting.
Thanks. If they are both good should I just buy the cheaper option?Quote:
Originally Posted by Clive S
Chaz I am afraid that the choice has to be yours alone. Are you using it to hold threading rod in a hole or bolt anchors?Quote:
Originally Posted by Chaz
I have 2 requirements. The first is to hold M12 nuts in place that allow me to tighten the bolts holding the rails in place.Quote:
Originally Posted by Clive S
Secondary is similar where ill either sink nuts for holding and mount hardware the same way (motor mounts etc) or where Ill epoxy thread bar in place. My preference is to sink the nuts so I can use bolts from the top.
Did you use the Red or Green Anchorset Clive?
I don't think you will have enough purchase with the nuts as they might pull out, also think about getting epoxy in the threads and the bolt will have to go right through the nut into some pocket or other. If you look at the chart on the http://www.ebay.co.uk/itm/ANCHORSET-...c=1&rmvSB=trueQuote:
Originally Posted by Chaz
it shows how deep the hole should be for a 10mm rod
Re the colour I have to pass but you could phone Sika up and ask their techy guys.
Thanks. For my current epoxy I was drilling a 30mm hole which is a pain in the ass but allows full cover to the top and sides of the M12 nut.Quote:
Originally Posted by Clive S
IVe ordered one of each, will try them and see.
Main gantry poured, will post pics later.
Used a bit less plastisizer this time. 950ml per 25kg of cement. I tried with the minimim recommended amount of 500ml but not enough water so the mix was really tight.
Wow, 3 months have gone, I am piss poor at keeping this thread updated.
So gantry was done, Y motor mounted, some test movement here:-
https://www.youtube.com/watch?v=5sMb4XmzuXc
Ignore the last 100mm or so that is unsupported. Long story, That will be epoxied it later.
A pic of how it all looks, my wife not happy with me taking pics of her. Testing the fit before I attempt to epoxy this lot together.
https://c1.staticflickr.com/1/286/30...a215bdb6_b.jpg
Wow, i cant wait to see that monster finished.
Same here but sadly probably still a few months away.Quote:
Originally Posted by Boyan Silyavski
...seems to be a lot of water.Quote:
Originally Posted by Chaz
In my work place we add circa 30 litres of water to 750kg of mix (all depends how wet is the sand).
This gives nice mix to form roof tiles. 10% water too much and mix is too wet and have to be dump - happens daily.
My point is to get correct amount of water - mix it well and we shall get strong cement.
Really? I was under the impression this was a fairly dry mix. Without the plastisizer it wont even bond.Quote:
Originally Posted by Tom J
Should add that the mix goes through bed/slipper which is kind of mold and is compacted by packshaft with fingers - layer of concrete is 12mm thick and travel 1m/s speed.Quote:
Originally Posted by Chaz
In your case vibrating plate is a must. Curing process is complex too (4 stages with extra water), retarder is used to slow curing process.
Since I work there, I use min amount of water (just for mix to be not brittle) - for diy concrete job
Tom I am not sure you are understanding this way of moulding concrete as it is done with superplasticiser which makes a very fluid mix and MUST NOT be vibrated as it will settle the aggregate to the bottom. The way it works is that it separates all the individual fines and stones in suspension for about half an hour then they come back together for the set.
This explains it better. https://www.youtube.com/watch?v=9ySyaKb2_b0 and here https://www.youtube.com/watch?v=ICp4...w#t=107.971789
Agreed with Clive S, plus, this wouldnt be something I could do from my garage ...Quote:
Originally Posted by Tom J
Plus, there is no air bubbles in my mix, this I am certain of.
ok, I was referring to cement mix with coarse sand. Got your point guysQuote:
Originally Posted by Clive S
This works the same with say 22x15 aggregate but they grade it down using smaller and smaller aggregate down to ash.Quote:
Originally Posted by Tom J
I am looking at building a concrete mill with Dean's help using this method. We shall see.:barbershop_quartet_
its good for heavy work like milling in steel where damping vibration is important. Technically should be easier to build, considering your planes are smooth, even, leveled, squared etc.Quote:
Originally Posted by Clive S
All mounting surfaced for rails, bearings etc can be prepared - machined and than fix to the mold by precise adjustment before mix is filled in. That is how I would do and will in one day.
Done on one of these Attachment 20106Quote:
All mounting surfaced for rails, bearings etc can be prepared - machined and than fix to the mold by precise adjustment before mix is filled in. That is how I would do and will in one day.
I can't believe I just found this thread ! About four or five weeks ago a friend of mine sent me a link to a machine that he was considering, very similar to the machine you are building ! The only thing that concerned him was the fact that it would be coming from foreign shores, (vat, customs charges, shipping etc) I must point him towards this thread and see what he makes of it. Anyway, here is the machine he was considering, as you will see, the similarities are there:thumsup:
http://www.ebay.co.uk/itm/CNC-Millin...p2056016.l4276
Ive seen those machines. Looks 'nice'. Similar idea, certainly, nothing really new with a fixed gantry idea.Quote:
Originally Posted by needleworks
That machine is ex Austria so no import tax etc. It's a fair bit smaller / lighter than my machine. Probably worth a look at that price (compared to say the Chinese imports).
Here's a vid of it cutting - https://www.youtube.com/watch?v=oSO0BlGFaqA . The one on sale only as a 2.2KW spindle, the one in the video is almost 4KW.
I have cast iron one 275kg. This help me a lot with my weldingAttachment 20114Quote:
Originally Posted by Clive S
These lovely welding benches :)
How do you keep spatter off of them?
Dave the one I linked to is 150mm granite so the splatter does not stick:cower:
I need to finalise the location of the gantry. From what I can see, the 'best' location for the spindle centre line is the middle of the machine. Keep in mind that once the gantry is fixed, its fixed.
Any reason I would not have it in the middle of the machine? The table pretty much moves the full distance of the table, except around 30mm to the rear which is where the ballscrew bearing holder is.
I could play around with table sizes, considering having a tool rack if I go with BT30 and like the Datron machines (but they are moving gantry) have tools mounted on the rear of the table for the ATC. Most of the machine images I can see online seem to feature the spindle generally in the centre of the table length.
Bring table to front of machine then spindle line is on or just past the inside edge of table. Allow for largest tool diameter if want to get maximum cut out of it and have travel for it.!
To be honest Chaz your wide open to world of pain if you haven't at least drawn this out on paper. Just basic Cad model will highlight any potential clashes. So many Gotcha's waiting to bite I wouldn't dream of building without basic model. Will save you time and money in long run because often these Gotcha's bite after it's too late or major hassle to change.!!
Second what JazzCNC said, even a dimensioned 'fag-packet" sketch will highlight important bits that (and have) goofed up a machine build ;)