Holes are smaller than expected

Hello,

It's been hard for me to configure Skeinforge to work decent prints and I could print a calibration square with almost perfect dimmensions.

Now I want to start printing spare parts for my prusa V2 metric and I found that the holes for the bar-clamp are 7mm in diameter but the STL file says 8mm.

I've read something about an arc compensation but I didn't understand that behaviour and how to configure for a 0.5mm nozzle.

Thank you.

---

Ernesto Pareja

dcctrains.netne.net

There are various reasons why holes tend to shrink when we print. My m8 holes are 9mm, m4 is 4.5mm and m3 is 3.6mm. (I believe these are standard prusa sizes?) Do some test prints to find how large you have to make the holes.

Or you could use polyholes, which nophead explains in depth here: [hydraraptor.blogspot.no]

---

--
-Nudel
Blog with RepRap Comic

I'm printing the Github parts for mendel metric V2 so I cannot modify the file.
i'm wondering how my mendel parts where printed then because I did't have to file the holes.

Is there any library that has corrected the hole size for mendel parts or everyone has to file them?

Thank you

---

Ernesto Pareja

dcctrains.netne.net

epareja Wrote:
-------------------------------------------------------
> I'm printing the Github parts for mendel metric V2
> so I cannot modify the file.
Yes you can. Get the source folder from github and generate new stl files with OpenSCAD. The variables for hole sizes is in metric.scad

---

--
-Nudel
Blog with RepRap Comic

i had a problem last night with a print being too small.

8mm hole was too small (was printing a fishbone gregs gear)

im pretty sure it was because the layers were too squashed making the holes smaller.

never had a problem before and i was messing with start height last night

might pay you to try raising the head a bit more see if it helps

Thank you @Enlightx. I'm playing also with the Stretch parameter (Perimeter Inside Stretch Over Perimeter with - ratio).

I activated the plugin and printed 8mm holes with 0.32, 0.42 and 0.52 in the parameter.

The 0.42 was the most accurate.

I will try also with the nozzle height.

Do you recommend 1 sheet or 2 sheet of paper between the bed and the nozzle? The paper would be tight or loose?

Thank you

---

Ernesto Pareja

dcctrains.netne.net