[peteeng]

Come on Guys - Move along - Making good machines is a tough gig. Pick another subject. Some people are destination oriented and some are journey oriented. Both are fine...Life's too short to niggle. Peter

[ardenum2]

Hi,
no mistake, its just what you think, have you actually made it? When you have then tell us what you have done and how much it cost, until then its all speculation.

Craig

I'm starting to think you're just pulling my leg, wish there was a block function on the forums, the occasional good comment from you doesn't seem worth all the annoyance that you cause

ok Pete moving on...

[joeavaerage]

Hi,

you tell me
your reducer cost under $100 so I'm very confused how you ended up with a few grand for the whole setup, it just doesn't add up.

No, the reducer cost $180USD. By the time I had it in hand, in New Zealand, it cost $635NZD. Likewise the servo kit cost $438USD but with shipping it cost $1000NZD.

All prices in New Zealand dollars including GST:

750W Delta servo kit $1000
Atlanta Drive servo reducer $635
Trunnion table and trunnion sides 32mm plate and 20mmm plate respectively $242
4140 round for platter (150mm diameter x 180mm) $161
Machining trunnion table $300
Machining T Slots $690
Toothed pulleys (2) and toothed belt $64

Total (to date) $3092

Projected costs to complete:
400 mm 50mm 4140 round ( to make alignment jig) $50
bearing (trunnion free end) $50
Trunnion end plate (32mm steel plate) $100
Upstand (140mm) for fourth axis, ie trunnion drive. $100

Total (estimate) to complete $300

So the total cost in NZD is $3400 or $2040USD

This is for the trunnion table and fifth axis platter, and does not account for the fourth axis.

All in all I would call this an expensive endeavour, and remember the fifth axis is only 150mm in diameter, ie a small installation.

Craig

[peteeng]

Morning All - Lapping plates update - I have done some lapping today with the P80 grit paper. Then I use a water film as a transfer contrast to see how the surfaces are going. Using B as the reference the A plate is a bit hollow and the C plate is a bit crowned. I shall smear some epoxy putty across these now to see what happens. I have to dry them properly first. If I place the plates together dry they float a little but since they are the same size they stop floating when they slid off each other a bit.. . If I use a thin water film they suck together really tight. So I think I'm close... Peter

[peteeng]

Hi all - I puttied the laps and realised that I should have left the reference plate unputtied to use it to lap the other two. But the putty will cut fast to reveal the hollows (that's the plan) until tomorrow - Peter

[peteeng]

Morning All - Getting back to casting grout. I've started designing/building a 8x4 router called Lanky. I'd like to cast the walls but a bit of homework says plywood is better in terms of weight. I designed the walls in ply and they would weigh about 25kg so to cast the walls solid I'd need the density to be around 400kg/m3 which is doable in lightweight concrete but I don't think it will be stiff enough at that density. So then I'd have to do some sort of voiding or webbing. Even using ply as webs and aluminium skins is stiffer and lighter. I'll set up a Lanky thread... Peter

[peteeng]

Evening All - A good day lapping! Flattened out the epoxy and the plates are getting better then 0.001" hollow. I'm wondering how a hollow surface produces a hollow sister? But the hollow is getting less and I have started to rotate the lap, that seems to be making faster progress. The water transfer contrast is getting to very high coverage and they float and suck really well. I have been in touch with a company that has a very sophisticated geometric laser system for setting up cnc's. I have asked if I can use the laser to measure the laps... they owe me a Favour or two. We shall see how they respond.

I don't think I would screed the surface again. But the sealing and the putty knife across the surface I think is worthwhile. The surface seems to be better sealed... Peter

[pippin88]

Lightweight concrete does not look any good for our purposes. I looked at it a lot. The loss of stiffness is greater than the reduction in weight compared with normal concrete.
This was mainly for polystyrene (EPS) lightweight concrete.

[peteeng]

Hi Pippin - Totally agree. I'm about to do a test cast with perlite and grout just to see what it feels like. Maybe a good filler... concrete/perlite 1 concrete : 8 perlite is 350kg/m3 (mix by volume) so its light! So 1:4 is 576kg/m3 so less dense than plywood. Been trying to get 400kg PU foam but the supplier has it in 200kg lots... Keep coming back to good quality plywood and al laminates... Peter


Overview of Perlite Concrete - Perlite Institute

Perlite Concrete - insulating concrete - Ausperl Australia

[peteeng]

Hi Pippin et al - A note about mixing concrete/grout/UHPC fairy floss etc. Use the two container method. Mix in one container then pour the mix into container 2. Scrap out the unmixed plague from container 1 into C2 and keep mixing. Then pour it pack into C1 to check its all mixed. Repeat as needed... If all good, then pour into mould. Plus add powder to water gradually, not water to powder..... Peter

[peteeng]

Hi All- re checking my laps. I could buy a small calibrated surface plate and contrast check my plates. That's doable, plus this week I'm trying to get rougher grit paper then P80.. Peter

[peteeng]

Hi All - I tried using a dial guage and stand as a repeat0meter and I was quite surprised at how good the surfaces where (good for me anyway) The A plate is good to +/-0.01 the C plate is about 0.03. The A plate has had the most work on it so I'll continue using it as the reference until the others settle a bit better. The guage stand occasionally rocks a little so a 3 point foot would be best. So I'll keep lapping and keep observing. Using a water film as a transfer contrast is useful as well, must be really thin its not "wet" just damp. Getting good transfer ratios showing up the hollows, not many now. Peter

[peteeng]

Hi all - I now know why a repeatometer is heavy and stable. Doesn't take much to upset a 0.01mm dial guage let alone a 0.0005mm comparator. I'm now on the lookout for a 0.001mm dial guage to make a better one with. I did upgrade the current one with a hard follower and averager. Works much smoother now... Peter

[joeavaerage]

Hi peteeng,
I have a digital Mitutoyo dial gauge and it does 1um. Be careful what you wish for.....its bloody hard to use because its so sensitive.

I have been making a little progress too. I have used an alignment tool I made to attach the trunnion cheeks. I found and old part off my mini-mill that I can re-purpose
as an upstand for the fourth axis driver, at least until I get around to making a new and better one or casting one. All I need now is to make the offside trunnion axle stub, bearing
and bearing upstand. Getting closer by the day now!

Craig

[peteeng]

Hi Craig - agreed - Peter

[Momentz]

Have you got any suggestions of a retarder to use to slow the curing process down for bigger pours?

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[peteeng]

Hi Mom - Speak to your supplier they will have retarders. But I expect you won't need it... If the mould is prepared and your organised its pour it in the hole and wait... Peter

[Momentz]

Hi Mom - Speak to your supplier they will have retarders. But I expect you won't need it... If the mould is prepared and your organised its pour it in the hole and wait... Peter

I'd like to think so. I worry about mixing up 200L one bucket at a time and having it go off.

I know you memtioned 2 hours before but others I spoke to over the last few days have mentioned it set hard in 20min? I can't mix 20 bags in 20min

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[peteeng]

Hi Mom - They cast enormous dams in one piece yet they pour in small amounts. Get some of the grout your going to use and make some blocks. I've had several trivets and pavers under test for years... Some of the CSA grouts used for repair go off very very fast as they want the road or runway or whatever back into service quick. Thats not the type of material you want. Peter

[Momentz]

Hi Mom - They cast enormous dams in one piece yet they pour in small amounts. Get some of the grout your going to use and make some blocks. I've had several trivets and pavers under test for years... Some of the CSA grouts used for repair go off very very fast as they want the road or runway or whatever back into service quick. Thats not the type of material you want. Peter

Thanks Pete,
Will go and get a bag of lanko 701

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