The very afternoon after I posted this comment, I was driving on my way to do a little bee job & this is what I found:-
Apart from making lids, bases & the odd bee box repair, I might even be able to make a few entrance reducers.
Thanks, sounds like an excellent idea.
I designed a frame for my mouse guard and added a reducer. It hangs on existing screws on my slatted rack with keyhole hangers. The reducer is wide enough to add a larger opening on the other side, which I plan to do in spring. Will also be adding a swing latch to ensure reducer doesn’t slip out. For extra security to keep the frame attached to the box, I will be adding “z” swivels from the upper screws.
@Gerald_Nickel and @Dawn_SD - just a short comment to say thanks for your previous posts about dimensions for the entrance reducer. I used the comments/dimensions in your posts to make my reducer for winter this year. Cheers!
I haven’t seen the follow pic on this forum yet, so I though I’d share it with you. It helped me a lot.
I really like that idea 
Being a beekeeper and a 3d printing person, we always want to make simple things complicated by taking something that could be easily made in a few minutes on a table saw and making it something that is more precise than it needs to be and then taking several hours to print it. On an environmental note, I am printing these out of PLA which is a corn based plastic that may be safer for the bees than ABS if they start chewing these things up.
Back to the complicated part. I made versions that are 325 mm long and 320.5 mm long (my hive is sitting 90 miles away from me while I am here in Houston, Texas as is my printer and I have seen two different length measurements on different threads, 325 and 321mm. My original versions are 12x12 mm and those two lengths. After reading through this thread it was noted that the opening tapers from 13 mm down to 12. Based on that, my 12mm versions should fit but I decided to complicate things by making them taper from 13 to 12 mm on two sides. Why two sides? Well because each reduce has two different width openins, 20mm on one face and 40mm on the other. So they need to taper on two face in order to rotate and wedge in in each orientation. The opening heights are 8.5 mm. I saw some people are making them 8mm. I don’t think the bees care since the unblocked opening is 12mm high.
If anyone has a printer and wants to try them out, they are on thingiverse at https://www.thingiverse.com/thing:3972427
Welcome to the Flow forum! Great project you have undertaken there. Very impressive. I will be fascinated to hear whether they fit well.
The dimensions above were from a Flow Hive Classic. Mine was actually down to 9mm at the inside edge of the entrance. If you have a Flow 2, the fit may not be the same. However, your experience would be very valuable.
Hi Richy, is this stuff UV stabilised? Can you get UV stabilised consumables for the 3D printers at all?
Yes indeed. I do this all the time. SHMBO always asks “Why on earth don’t you do the simple and easy”
I say “where is the fun in that”. When complicated doesn’t work you can go back to simple and easy (which I also do often). 
All that’s needed for an entrance reducer is a piece of sponge rubber. Jam it in before winter, then the bees will open it up if they want to after winter. A strip of sponge rubber: entrance reducer solved.
Yes, JeffH, but that is too easy. And down here, our bees don’t necessarily completely hunker down for the winter. We can have strings of 75 degree days in December followed by a cold snap and then reach 80 in February.
I have had several things printed out of PLA outdoors 24x7 in our Texas sun and heat for several years without any decomposition. They are not UV stabilized but also do not break down. Also, each one contains 49 cents of plastic and takes and hour and a half to print. My time is limited to pressing the start button and removing the part, less than 1 minute. I can knock one of these out once the design is confirmed as needed in much less time than it would for me to make one on my table saw. There is also no risk of cutting a finger off and I can do the bevels easily which would be difficult on such a small piece on my table saw. Lastly, the two 3.5 mm thick areas above the holes are much stronger than they would be out of pine or cedar. Not a big issue, once installed, I know. I am also a woodworker so that was what I was originally thinking of doing. But it turns out there are a lot of beekepers who also have 3d printers based on comments on bee related things on thingiverse. the nice thing about the bevel is that it can go in as far as it needs to get stuck. Once I try it out, I will adjust as needed. My bees were a little protective last weekend due to our cold weather that day and it is colder this week so I will put on my bee suit next time and get the smoker out before testing this out. Also folks, don’t worry, I don’t plan on printing a smoker out of plastic.
ROFL! 
So glad you joined the forum. You have my kind of sense of humor! 
I understand that you wont 3d print a smoke, but what about a smoker buddy.
Actually it’s not a silly idea. They 3d printed some hex shaped native beehives at the Sunshine Coast University. They are similar in size to what I’d imagine a smoker buddy would be.
A printed smoker buddy would quickly melt with a lit smoker in it.
You mentioned the hex shaped native beehive. I made this the other day. It is modular made from cubes that you can mix and match the sized for different size wild bees. Framed in cedar from a spare fence picket.
No science to the sizes just based on wild bees I have eyeballed around our place.
Here is a better photo.
Hi Richard, I agree, it’d probably melt the plastic. I’m thinking I should make a wooden one, hive buddy that is, with a telescoping lid 
Someone will say “yeah but the wood will catch on fire”. I wouldn’t agree with that.
Cherry wood makes great pipes…some would could say smokers.
Hi Busso, it just occurred to me that my message could be interpreted that I meant bee smoker. I just now edited my reply to mean “smoker buddy”.
