Last question first 
The center blades are fixed.
I just grabbed nuts and bolts from a bin. I don’t know the size.
Inserts would likely be great. I didn’t have any.
My prusa printer is old and likely slower than yours.
I have been working on my “Honey Do” spring list, so no I haven’t upgraded the Thingiverse upload.
Let me look at what is on there. I may have an updated STL.
I just posted an untested updated 225mm version. I have not tried printing it because of printer issues.
The thought was to print it larger and anneal it, hoping it would shrink to 215 approximately.
If you don’t want to anneal it, slice it to 215mm xy and 20mm z.
That should work…probably 
Thank you for the quick response.
I’m going to try not annealing. I might try it in ASA given its enhanced strength, impact resistance, etc. If so, I’ll report back here.
Thanks. I would appreciate it.
I suggest a 25mm x 2-3mm washer (outside diameter) under the outside blades.
I printed them.
Morning all. Just quick question.
When did all door ways become memory erasing portals.
It makes it really hard to get shit done
Sorry, I forgot the question. 
My plan is to carefully anneal the edges for some additional strength without too much shrinkage.
Note. I’ve added material to the outside edge. Mine cracked there.
The holes are slightly less defined. The added material intruded into the holes and I was too lazy to clean them up.
I would suggest using Polycarbonate Carbon Fiber when printing these. PETG doesn’t have very good impact resistants.
Adding carbon fiber or ABS has been suggested but I haven’t tested them.
If anyone does please let us know. 
Recent testing has shown that carbon fiber filaments may actually decrease strength due to the fact that it leaves voids in the printed object. For years I believed that it improved strength but I am re-evaluating my opinion. I have about 36 rolls of CF filament including PC-CF.
That’s unfortunate.
I make under hood car parts out of it all the time. No failures yet.
I have the Y mower, I will design and print some pc carbon fiber disc for it. I will keep the weight the same as the OEM disc to keep motor amps the same.
CNC Kitchen for the win! Everything there is to know about CFPA!
Stefan is awesome. I became a Patreon member when he quit his aerospace job to become a fulltime content creator. That was ballsy. Check out IBuiltAThing.
Love his channel. Extremely thorough.
Very nice design, the blade holders look like they can also cut grass.
