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Feb 06, 2017, 04:13 PM
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I think the other shaft sizes are fine as-is; the 8mm thing was mostly just a convenience issue as it would be easier/more convenient to get an 8mm-8mm coupler. In any case, the 65mm version is very low on the priority list and I probably won't be building one for a while yet.
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Feb 07, 2017, 11:16 AM
Jetdrives R Us
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Change of wear ring


I forgot to draw what the inside of the intake channel will look like, and while doing so came up with what I think is a better way to arrange the stator housing. Instead of having the wear ring on the stator it will be better to have a 'locator' ring on the pump body and have the stator housing be the wear ring. I had located it in the stator originally to make an easier installation, but it makes more sense to have it this way to keep the intake channel congruous, and the flange should cover any discrepancies when cutting the hole. And now you just replace the stator housing if you wallow it out with use. I also had depicted the pump wrong when the stator is installed, there will be a gap (say, 8mm on the 35mm prototype) when pushed together. You just file/sand down the end of the locator ring to make the pump fit a variety of transom thicknesses. There should be a small groove in the stator that the end of the locator ring fits into to keep things neat.
Feb 09, 2017, 05:02 PM
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Hi guys, I am ordering my first 3D printer in the next month or so. I'm thinking about the Monoprice Select Mini 3D printer. It looks pretty good for the price and it's just a starter. I am a tool and die graduate, so I have master cam X and other design and g-code generating software. Can I use this for 3d printing?

Can't wait to try making my first jet drive
Feb 09, 2017, 07:23 PM
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That looks like a good one. As Juss told me, if it has a good support group that's a plus. And I like the compactness - and that it comes assembled! What might concern me is the 120x120 bed size, it would be a little small (4-3/4" sq) for some projects. I wound up getting a Geeetech Pro B i3, their copy of the Prusa i3. It has similar specs, a larger 200x200 bed size, but you have to put it together. I'm going to start on that tomorrow - but a time-lapse video of assembly on Youtube wears you out just watching it!. We'll see how it performs, I have some PLA and ABS rolls for trials.
Last edited by sundogz; Jul 28, 2017 at 10:00 AM. Reason: sp
Feb 09, 2017, 08:29 PM
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Quote:
Originally Posted by Reefsider416
Hi guys, I am ordering my first 3D printer in the next month or so. I'm thinking about the Monoprice Select Mini 3D printer. It looks pretty good for the price and it's just a starter. I am a tool and die graduate, so I have master cam X and other design and g-code generating software. Can I use this for 3d printing?

Can't wait to try making my first jet drive
So I don't have a ton of experience with different printers but I do run one for work so I know a fair bit about printing in general. A few things I will note on printers, you really do get what you pay for in the long run. There are printers in the $200 range and up. The cheaper printers usually require assembly and are just built out of cheaper parts (bearings, slides, belts, motors, etc) If you like to tinker and upgrade things, then the cheaper printers are fine, if you just want it to work and work consistently, the pricier models are where its at.

As for the one you are looking at, I would look for something else. You will quickly be disappointed with the small build size. Also the arm on top isn't supported on both sides, this will cause for z axis deflection likely. If you are stuck in the $200 price range (which for a first printer is a fine place to be) I would go with a prusa i3 copy of some sort. There are tons out there, they are essentially all the same. The ones that sundogz got looks like a good machine at that price point, I've also heard a lot of good things about the tevo tarantula. If you are ol spending some more, I would go with an original prusa i3.

as for software, there are a lot of free slicing software's out there like slic3r or cura that work fine. I use Cura on my printer at work half the time and it does an awesome job.
Feb 09, 2017, 09:36 PM
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Ok thanks guys I'll do some more shopping and research. I would actually prefer to build it myself as long as it works as well or better than the monoprice mini.

I'll keep you posted as to what I find
Feb 09, 2017, 10:37 PM
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Juss, did you get the PM I sent you this morning?
Feb 10, 2017, 09:10 AM
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Quote:
Originally Posted by sundogz
Juss, did you get the PM I sent you this morning?
Yup, just been really busy at work so haven't had much time to put in to this at the moment.
Feb 14, 2017, 01:47 AM
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Printer


After much deliberation and study I decided on a Prusa i3 clone - the Geeetech i3 Pro B. It had what I needed in a printer at a price I wanted to pay. I found one on Ebay that was here in the States for a better price than from overseas! It has a large 200x200x180 build volume, a heated glass print surface, a .3mm nozzle and prints with most types of filaments. It also had an SD card reader for offline printing. It arrived within a week, and took me 3 days of off/on building to get it put together. It is a very recent manufacture - the sticker on the power supply says it's less that 4 months old! I took my time and made some small changes/improvements as I went. It comes with stainless shafts and rods (that's lithium grease on the threaded rod) the upgraded metal extruder mount and bearing brackets (not 3D printed counterparts) and is a very tight machine - I mean no slop, tolerances are very small. It has an 8mm acrylic frame which I decided to make even more rigid by CA gluing the seams after assembly. It's rock solid. I also got the optional 3D touch auto bed leveler sensor as it is purported to improve print quality noticeably. I'm considering getting a cooling fan/shroud to cool the object as it prints it as it is supposed to allow for sharper corners/edges. There were no missing parts - matter of fact there were a bunch of extra screws and washers (I didn't use washers when building the frame - there was no need to). I'm now in the process of downloading the software for it and studying how to use it. I bought several different colors of filament in PLA and ABS from Protoparadigm since they have a $5 spool deal and are located in the States. But you get more from your money from China so once I decide what I'll be using (probably ABS black) I'll get it in bulk spools from there. I'm considering making a cover to keep it free from dust when not being used but may wind up making a plexiglas box to cover it, we'll see.

Right now I'm waiting on a part for a broken laptop that has Windows 7 OS (most 3D software requires at least win7) before I load software and calibrate the printer. I should have it going by weeks end.
Feb 16, 2017, 11:51 AM
Jetdrives R Us
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Bearings, impellers


In keeping with the printable/useable theme I believe we could print and use our own impellers for the first three sizes of pumps. The smaller two (15 & 25mm) can be pressed on the shafts with CA glue on both ends to hold it securely. The 35mm could maybe use a drive dog with a cone shaped skirt in front of the dog. The larger drives would do best made in alum or steel by Shapeways and fastened with a grub screw on a flat on the shaft. Only testing will tell.

Bearing pockets would scale fine, but because of the limiting factor of small holes and 3d printing the smaller two drives might do best with a sleeve and bushing (or drilling the bore after printing). Also, 3D printed stator blades turn out chunky in the smaller sizes. Maybe try a one blade 'speed' impeller (wraps once around the shaft) in the 15mm drive with a two fin stator to keep things uncluttered. And 2 blade (overlapping 60 degrees) impellers with 3 fin stator for the 25 & 35 mm pumps. An finally, three blade impellers and 4 fin stators for the 55 & 65mm drives.

This means the jet body would scale, and we'd only need custom stator housings and impellers. Just thinking out loud...
Feb 16, 2017, 01:58 PM
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IMO:

15-25mm: 2-blade impeller with 3-vane stator. (Could experiment with 3-blade impeller on the 25mm as well.)
25mm-35mm: 3-blade impeller with 3-vane stator that has radially skewed vanes if there is concern about "pulsing". (See pics.)
45-65mm: 3-blade impeller with 5-vane stator. Maybe 6 for the 65mm.


Feb 16, 2017, 05:57 PM
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There is a limit as to how thin a blade/fin can be made on a 3D printer. A thicker blade is not a problem per se, unless they are taking up too much area (as in the smaller drives) and limiting the water flow. I understand you referring to other drives, but we are not limited to that train of thought here. I do believe a two bladed stator will do the job, and do it better that three (3d printed - thick fins) can in the small drives. It just needs to straighten the flow from a swirling mass to a jet of water. And don't discount a one blade impeller, it can be done successfully - maybe it will be just the thing for the smallest drive. Your suggestion for skewed vanes has merit and may be beneficial in some sizes, but not the smaller ones - it would take up even more space than straight vanes (think fat 3D printed vanes).
Feb 16, 2017, 10:30 PM
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I suggest using a drive dog with a cone shaped front for all size jet drives, it makes replacing and trying other impellers so easy. Another plus is you only need one shaft, but you can have a huge amount of impellers to try on that shaft.
Just an idea, do with it what you will.
Feb 16, 2017, 11:36 PM
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I could only find drive dogs for 3,4, & 5mm shafts, but maybe there is a source I haven't checked. Also, only testing will tell if the larger size printed impellers will hold up to being driven by a dog - that's a lot of torque.
Feb 23, 2017, 09:38 AM
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Quote:
Originally Posted by sundogz
I could only find drive dogs for 3,4, & 5mm shafts, but maybe there is a source I haven't checked. Also, only testing will tell if the larger size printed impellers will hold up to being driven by a dog - that's a lot of torque.
Maybe you can go with 1/8'' and 3/16'' drive dogs since they are readily available

3mm = .118 1/8'' = .125
4mm = .157
5mm = .197 3/16'' = .187

Yes it is a lot of torque, maybe a little silicone on the shaft and impeller before installing it, to help hold it so the drive dog doesn't take all the load. It should still be removable too with the silicone.


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