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My scope was able to save this image:
505794
I've marked the "high" and "low" peaks i was talking about. Their values is 1110mV and 496mV in this case. I ignored the first part of the curve because...

Are you sure about #1? In my tests it seems like the force applied only changes the maximum amplitude and does not affect the frequency nor the decrement. However, the "noise" i see in my data might...

so...i spent the day wacking a epoxy granite sample with a screwdriver, how about you?

Executive summary: I don't think i'm smarter now than i was this morning...maybe more confused, but not...

Yeah, well, my reasoning was that they aren't connections between "loadpoints" during normal operation, so i don't think it would be an issue...but i'm not an expert on this by any means :-) I opted...

Thanks! I'll look into it!


I bought 4 of them because i knew i'd mess something up;-) I glued it since i wanted to make sure it did not "move", not sure how much of an issue it actually is...but...

Yes, I have multiple M16 threaded rods through each casting. They served two purposes:
1. I was worries that the weight(750kg and 1000kg) was enough to make the forms "bulge", making the sides of...

So, i tried something :-)

I superglued a "cheapo accelerometer"(https://www.digikey.com/en/products/detail/adafruit-industries-llc/163/5353580) onto the end of one of the samples and tried to fix...

...i agree with Peter, you need webbing...it is a lot of weight! Also consider the surface below...it it isn't straight and flat, your mould will bend! The floor where i poured mine was uneven and...

A lot of talking to my self here, but i just ordered a couple of accelerometers. I'm going to see if something can be concluded from that...

/Thomas

Maybe an acceleration sensor, fix the sample in one end and "hit it with a hammer" in the other? I'm unsure if the damping is frequency dependent or not? If frequency can be ignored then length and...

Yeah, well, i have a lot of stuff, but high speed cameras is sadly not on the inventorylist :-( Apart from this, the deflection will be very small with these sample-sizes...so i don't think this is...

Yeah, i'll see if i can order the stuff for a test af that...it will take a couple of weeks since i have a lot of traveling in the upcoming weeks...

Maybe i should figure out a (simple) way to...

Yeah, when i see cutouts of "professional machinebases" they usually have very large aggregates embedded(guess: size=50-80mm!) within them. But it also makes sence, less flexible epoxy=stiffer. The...

Yeah, i could, but not sure if there could be anything interesting to figure out in the process?

PS: I've been thinking that i should try adding larger aggregates to see what it changes. The...

So...the results are in...short answer: 22-23Gpa...for a 12% by-weight Silimix282 with R&G ResinL + GL2 Hardner. Cured for 2 weeks at 30c, no postcure treatment.

I've attached an excel spreadsheet...

The biggest size is 4mm in the Silimix282...if this works out fine, i think i'll cast a couple more, but with some larger aggregates in...

I'm not sure if i can calculate anything that will tell...

Yeah, i made a spreadsheet that does the calculation:
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Its just a calculation for a midspan load on a beam supported between to points. So with a guestimate of E=20Gpa a load of 100N will...

How much weight did you use in your tests and what sort of deflection did you measure at what distance? Did you do a cantilever test or at 2-point setup with load in the middle? I'm planning on doing...

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...casting done... i tried the blue die this time:cool:

They've been placed to cure in the furnace room at around 27-28c...so demolding in a couple of days i think...

...i think i'm...

I had some spare phenolic plywood laying around, just enough to make two forms for 40x40x800mm test bars:
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...i'll cast some billets with my EG very soon and post the results here...

Defently :-)

I was planning on making 40x40mm square billets for testing, 800mm long... does that sound reasonable or ? I think my largest aggregate is around 4mm, so i'd figure 10x in size.... i was planning on...

Yeah, well, i've never been fully convienced about the dry-stacking idea for EG, however i don't think this is even an option with the Silimix282 ayways. Some of the aggregate is very fine, like VERY...

I was going to build a chamber for this. Some Ø150mm steel tube with flanges on the ends and then compressed air. And before the internet police arrest me, yes, i know it is "a bomb", but heavy duty...

Impressive planning! I've used soooo much money on shipping because i almost ordered each part individually...and sometimes the same part twice because i broke it the first time ;-)

Apart from the...

https://www.youtube.com/watch?v=24e8sDDS0ag

Got the controlpanel wired up:
503516 503518

...now i just need the mounting arm for it...and attach the backplate :-)

...on to the next part: finish wiring the main electronic enclosure!

Waiting for CycleStart/FeedHold and potentiometers(for feed/spindle overrides) in the mail...everything else got mounted:
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...its starting to look like something now :-)

A couple of...

The controlpanel starts to take shape:
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...next up: buttons and a ton of wires!

...not sure i understand you correctly here, but isn't the floating end of the ball-screw really "floating"? Mine is resting inside a bearing which sits in a housing with no(!) axial limits at...