I have a question for Rage 01 or anyone else that can explain this to me. These dies usually have two levels of holes where the ball bearing goes. We can see this on Rage's screen shot. I understand this is supposed to accommodate different length bullets, but I still don't understand how or why its necessary. Also, how do you really determine how far up to put the holes? Someone please educate me.
I was just going to post that I’d love to see the insides of the dies. My mind things the ball bearing holds the bullet in place so as a case is driven up into the die it moves the sleeve and bearing up and when it engages a groove I assume in the die body it releases the bullet. When the nose or the ogive passes the bearing the bearing pops back out and stops the next bullet.
Hard for me to put into words and not even sure my thought process is correct
AutoCAD .DXF would work best. I'm using fusion 360. Thank you!Originally Posted by TylerR
They are on the drive.
Well I will be really interested if that .DXF works on his software. The last time I tried to open a .DXF (the big base) on Autocad it just loaded a blank screen.
So I just tried to load this Spring adaptor you put on.....same thing. In the command line it says,"Invalid or incomplete DXF input -- drawing discarded." Hope Fusion works better.
Maybe there's something I don't know here......wouldn't be the first time.....
I would LOVE to have dxf's of OpenScad files that worked in my Autocad......would make my life so much easier.
Until then it's back to learning how to code Scad again......and it's not going very well so far.....
Last edited by GWS; 10-31-2020 at 06:18 PM.
To answer your question, Yes I have a adapter that I designed. Really all it is a straight piece to connect them both together. I made my hole at the top of the dia the same size as the bottom of the dropper which was in your files. That way you can't mix it up on which way it fits.
Last edited by Rage 01; 10-31-2020 at 06:51 PM.
That is a tricky question:
You are right the holes for the ball bearings are for the different length of projectiles that may be used. The groove inside of the outer piece also dictates what size of projectile you may use.
Now the groove in the outer piece will determine how high the inside of the dia needs to be pushed by the machine for the projectile to drop. That size is also based from the bearing hole on the inside piece.
So for me what I did was measure the length of the projectile which was 14.75 on average and made the center of the hole in the center piece that high. I am sure there is different ways to get to this.
So now there is a hole on each side of the inner piece. One is 14.75 on center and the other is 3mm higher on the inner piece or the size of your bearing you are using.
Now this is were it gets interesting. The reason (in my logic) why the holes is off set is because if you don't the dia will feed more that one projectile at a time. the second offset hole holds the other projectiles up until the dia is reset, then it releases the projectile to sit on the first bearing. So another words the second hole (bearing) will fall into the outer groove.
Now the second set of holes was a crap shoot. I have printed about 50 of these things to figure that out because I did not have any other projectiles to measure it from. ( I have sent this dia to a user on here for testing because his projectiles were a different size than mine.) I would think if you are only going to use one size of projectile then one set of holes will be ok, but that is not going to be the case.
I hope this is clear as mud?
Raymond.
Haha yeah maybe a little bit. I appreciate the input. I think my strategy is going to be copy the spacing from existing designs and leave it at that. For the .45 I have the DAA die so I am just using that spacing. I still have not put it in the press yet, but I should be ready for that tonight or tomorrow.
Well I’m baffled. My printed 223 die uses one single bearing in the inner piece and it works perfect every time. The guy on thingiverse explains to only use one bearing and use the hole heights on the inner piece dependent on the length of your bullets.
Well, it opens and gives me a great isometric projection, but only one angle so I can't build the 3d model. I'll keep fiddling with this and try to make it work. I'm new at Fusion so I'll need some time.
I don't think any other format would help other than maybe .obj, but that might be only slightly better than trying to use an .stl which is awful.
I had heard that it only did 2 dimensions....then I heard there was a new 3d version of .dxf, but I doubt my 2015 Autocad can read those. But I don't even get an isometric. I will have to design parts from scratch or learn OpenScad, and I'm having trouble finding time to do that right.
Biggest problem is my old brain cells.....they don't remember new information without repetition....and that's a pain. I'm not partial to having to learn something over and over.
I am on the fence to use just one or two bearings. I think I am going to design it around two, but we will see. DAA uses three bearings. Hoping to post this .45 one today for you to try out.
To clarify, I mean two bearings placed in holes at the same height opposite each other, not two different heights. DAA has three bearings all at the same height.
Last edited by TylerR; 11-01-2020 at 11:49 AM.
Look forward to trying it. I don't see how 2 bearings would be a disadvantage. Maybe it's only one for 223? Dunno
Two bearings is where it's at. You have to be on your game for a single to work consistently. Meaning your printer can't be off on ID and OD of circles. With dual ball bearings there is alot more room for error and bullets coming down at full force won't hammer the dual setup like a single. If you're on the loose side with a single a heavy 230gr bullet dropping 2+ feet will pop out or get stuck. Three bearings is a bit much when trying to assemble these droppers, esp. if you've left the bottom half in the machine.
Appreciate that input. Right now the only issue with two in the .45 die is that there is so little clearance for the wall thickness on the screw in die base, there will be a section that will have a wall thickness of only .5mm, but the way it is designed it will be supported in the threaded section of the die holder, so I don't believe will be an issue. It will absolutely need to be printed with a .4 nozzle. I am also printing at high quality settings in cura and it comes out very nice.
Makes sense. the 223 little light bullets don't do much slamming.....LOL. I like the idea of 2 bearings
Just FYI. Ive been using Prusa Slicer and it has a pretty slick feature. Variable layer height. So for a collater plate I can print .3 layer height until I get to the top and important parts then it will switch to finer setting. Helps reduce print times.
I only have experienced RCBS's rifle bullet feeder that also uses ball bearings.....4. I'm curious how it differs from the DAA design and what you guys are doing.
On mine there is two bearings 180 degrees apart closed under the bottom bullet base, and two 180 apart just below the next bullet's base. The top 2 are open at rest.
The feed:
1. Rod (holding the 4 bearings) and the case rises closing the top bearings under the next in line bullet. It can do that because the rifle bullet points taper in.
2. Rising further the bottom bearings open and the bottom bullet falls into the "M" expanded case.
3. Rod is then lowered on the return stroke which closes the bottom bearings and opens the top ones letting the bullet stack drop one bullet to the lower bearing stop.
There is a threaded internal sleeve that one adjusts up and down to control when the bearings recede to prevent two from falling.....and of course many holes in the rod for the top two bearing for different bullet lengths. The bottom two bearings only have one hole location.
I've never seen a MBF die so I don't know how they work......but would like to know.
Heres' a picture to go with the description above....
Last edited by GWS; 11-01-2020 at 01:30 PM.
That system looks definitely a lot more involved. This video explains the DAA die in detail:
I remember when you first showed those RCBS dies GWS and my research, which may be wrong, was that the rcbs only allowed one independent bullet to drop. The DAA idea allows the whole stack to drop and in effect help push the bullet into the case. One of the reasons I like your "high" mounted on/off sensor, is that you get a massive amount of weight to help push the bullet into the case, and you will never have to worry about it toppling over.
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