Rob R Posted December 21, 2021 Share Posted December 21, 2021 One issue that doesn't help is the nuts on the axles I have are different diameters. I have parked that version for now and moving onto a plain hole through - for this case I don't need to quarter the wheel anyway so hopefully it is just a case of eventually landing on the right bore by trial and error. Here we have v3 with a 3.2 dia plain hole and a small chamfer at the rear to help the axle go in. On the printer soon. Rob 3 Link to post Share on other sites More sharing options...
MikeTrice Posted December 21, 2021 Share Posted December 21, 2021 Can I suggest you investigate eSun Hard Tough resin. Normal resin is very brittle. The eSun resin can be machined if necessary. 2 Link to post Share on other sites More sharing options...
Rob R Posted December 21, 2021 Share Posted December 21, 2021 (edited) Thanks Mike. I am currently using the Elegoo Water Washable Grey with the printer located in the spare bedroom/office. I can just about get away with it in terms of odour but anything smellier (ie a "normal" resin) is going to have to wait until the spring when I can reorganise shed and make it more workshoppy. Overall I haven't had any issues with the Water Washable, there are lots of reviews on interweb saying it cracks etc but I suspect that is down to part design (keep the cross section fairly uniform and no big thick lumps) and over curing. I usually cure in water (a jam jar full of "Corporation Pop" is enough for most things) on the Elegoo Mercury Wash and cure. First stage washing is in a 4 litre plastic container (ex baby bottle sterilizer) which gets put outside at regular intervals to cure the washed resin before disposal. I will keep playing for now, ultimately, if the wheels fail the tyres, axles and crank pins are all recyclable. Keep safe out there. Rob Edited December 21, 2021 by Rob R spellin' 1 Link to post Share on other sites More sharing options...
jdb82 Posted December 22, 2021 Share Posted December 22, 2021 18 hours ago, MikeTrice said: Can I suggest you investigate eSun Hard Tough resin. Normal resin is very brittle. The eSun resin can be machined if necessary. I have used the eSun tough resin in my own wheels - it certainly is tough, and works well for the purpose - I wouldn't say it smells any more than any other resin, and as Mike says, it machines excellently. The downsides are that it's not good at printing fine detail (although for most wheel applications this isn't an issue) but perhaps worst of all, it's an absolute pain to clean up. I use 99.5% IPA, and everything it still seems to cling to everything lie superglue! But, a good resin for the purpose :-) John 1 Link to post Share on other sites More sharing options...
Timber Posted January 17, 2022 Author Share Posted January 17, 2022 (edited) As requested outside of this thread but placed here for ease of sharing. An STL for a 24.6mm 16 spoke outside crank driver with thinner tyres. https://drive.google.com/file/d/1cLtPfhiIOeQGCLzuU94MeRko3e0QDS-v/view?usp=sharing Edited January 17, 2022 by Timber 4 Link to post Share on other sites More sharing options...
RMweb Gold Regularity Posted January 17, 2022 RMweb Gold Share Posted January 17, 2022 Why the thinner rim? Is that to suit SSMRS tyres? Link to post Share on other sites More sharing options...
Rob R Posted January 17, 2022 Share Posted January 17, 2022 (edited) Timber, Thank you very much for the latest wheel .stl Printing as I type. Simon, yes the thinner rim is for the SSMRS tyres. The original was a bit chunky, especially for the 1850's locos I want to fit them to. Sample below fitted to a short test axle. Rob Edited January 17, 2022 by Rob R stuff 2 Link to post Share on other sites More sharing options...
Rob R Posted January 17, 2022 Share Posted January 17, 2022 It is surprising how much bigger the wheel looks with a thinner rim. 4 1 Link to post Share on other sites More sharing options...
Timber Posted January 17, 2022 Author Share Posted January 17, 2022 (edited) Thanks Rob - they look good off your printer. I will be interested in feedback on the slimmer rim. Now I have the geometry and Fusion script worked out, it only takes a few minutes to produce a driver wheel STL so happy to help with anyone elses project if you need a plastic wheel. I have tried printing in metal but the shrinkage is unpredictable. However, I can add some thickness to the rim so that they could be a master for casting. Post casting the wheel it can be turned to size on the lathe. Edited January 18, 2022 by Timber 4 Link to post Share on other sites More sharing options...
Rob R Posted January 18, 2022 Share Posted January 18, 2022 New thin rim printed centre to the left, thick rim printed centre to the right, fitted into SSMRS steel rims. I will have to fettle the steel rims before final assembly, a little tickle with some fine emery on the front face is needed. The axle holes are round, I borrowed my sons fancy phone and the close up lens has distorted things a bit. Rob 3 2 Link to post Share on other sites More sharing options...
Rob R Posted March 19, 2022 Share Posted March 19, 2022 Test print of the 42 inch 8 open spoke wheels on the printer as I type. Printing at 3 different angles to determine the optimum. The flat will print quicker, the upright will fit more onto the build plate. Hopefully they will all be round and true. When it comes to sorting out the bore for the axle I am going to try for a "firm sliding fit" (as opposed to a "light press fit") to make assembly easier and to prevent any chance of the boss from splitting. A drop of loctite should hold it all together as, unlike a loco wheel, once the back to back is set there is no need to dismantle the wheelset. 1 Link to post Share on other sites More sharing options...
flubrush Posted March 19, 2022 Share Posted March 19, 2022 (edited) Rob, Have you tried printing the wheels directly on the plate with no supports? I did my wagon wheels this way and it worked very well - very quick printing as well. :-) One thing I did do was to put a small chamfer on each bottom edge to minise elephant's foot. I also cut down the bottom layers progressively to minimise elephant's foot and got it down to two layers with everything still sticking to the plate. The wheels were round - pretty well nothing to distort them. Jim. Edited March 19, 2022 by flubrush 2 Link to post Share on other sites More sharing options...
Rob R Posted March 19, 2022 Share Posted March 19, 2022 Jim, I haven't got that far yet. My one and only attempt at printing direct to the plate (not a wheel) did not go too well. The print was ok, it just shattered trying to remove it from the plate. I have drawn these with a boss both sides as per the drawings I have so they wouldn't sit flat as they are. They look ok straight from the wash but I need to get some tyres before I can proceed much further. I think the spokes could do with thinning out as well. Back to the fence painting now Rob 2 Link to post Share on other sites More sharing options...
Rob R Posted April 4, 2022 Share Posted April 4, 2022 Having a play with some 42" split spoke wheels. Just off the printer. I know I need to play with the shrinkage allowance but I am not sure if I need to "open" the spokes up a bit more. The prototypes I have been looking at are quite slender with very little gap between the spoke pairs. For some reason the raft has come out really thick. Something else to sort....... Rob 4 Link to post Share on other sites More sharing options...
Rob R Posted April 6, 2022 Share Posted April 6, 2022 Version 4 mounted on an axle. Runs nice and true (pushed on by hand) except for one end that has an eccentric pinpoint. Black resin next to save painting inbetween the spokes.. Rob 5 1 Link to post Share on other sites More sharing options...
apl31 Posted April 7, 2022 Share Posted April 7, 2022 Rob, Nice wheels. Are these (and the black ) wheels still made with the water washable resin? Link to post Share on other sites More sharing options...
Rob R Posted April 7, 2022 Share Posted April 7, 2022 31 minutes ago, apl31 said: Rob, Nice wheels. Are these (and the black ) wheels still made with the water washable resin? At the moment yes as that is all I am geared up for. They do seem strong enough - I have had to put little fillets in where the spokes join the boss and rim which has made a big difference. There is a bit of variation in the bore of the rims, 6 rims of which 4 are one size and the other 2 are both larger to differing degrees. If that is still the case on a production run then it is a simple matter of printing some centres with differing od's Black resin can be a bit problematical apparently due to differing exposure/curing times etc so I will back to the experimental stage until I can get the settings dialled in. Or just print them in grey and paint the centres before assembly which might be a better option all round. Rob 2 Link to post Share on other sites More sharing options...
Timber Posted April 11, 2022 Author Share Posted April 11, 2022 these look really nice. Link to post Share on other sites More sharing options...
MarcD Posted April 11, 2022 Share Posted April 11, 2022 I'm planning to do the same in S7 I have just ordered some wheel rims in a few different sizes. did you have to drill out the hole for the axle? only as some plastic can close up after you drill it so you have to drill it a second time? Marc Link to post Share on other sites More sharing options...
Rob R Posted April 15, 2022 Share Posted April 15, 2022 Marc, Just noticed your reply. The axle hole is as printed (2mm) but when sliced the file was enlarged 3% to allow for shrinkage. Because I have put the full width boss on these wheels they go onto the axle nice and square (just winding them in by hand rather than a straight push at the moment). Getting everything nice and clean is important as the slightest bit of debris causes the rims to sit off true. Still experimenting at the moment, latest version has a substatial chamfer on the outside of the rim to reduce the chances of problems there. Rob 1 Link to post Share on other sites More sharing options...
MarcD Posted April 15, 2022 Share Posted April 15, 2022 Hi rob thanks for the tip Marc Link to post Share on other sites More sharing options...
Timber Posted March 12, 2023 Author Share Posted March 12, 2023 (edited) Fellow member asked me to create an STL for a Sharp Stewart 4'6" 14 soke 12" throw PB. Drawn to fit one of our 4' 6" Society Tyres. Here is the link to the STL in case anyone in the future also wants similar. https://drive.google.com/file/d/14nfTeNWd_wQQC4zRTY3tYxpvV2TbvSpW/view?usp=sharing Edited March 12, 2023 by Timber 2 Link to post Share on other sites More sharing options...
MarcD Posted March 12, 2023 Share Posted March 12, 2023 What resin are you using? I've found my centres fit the tyres initially but have a tendency to shrink over time. I have been using elegoo water washable grey. Marc Link to post Share on other sites More sharing options...
Timber Posted March 12, 2023 Author Share Posted March 12, 2023 (edited) I have successfully resin printed wagon and coach wheels together with some small manning wardle wheels. But for larger wheels I have also struggled using my resin printer to secure the quality I want. Therefore, I use Shapeways and print in their smooth fine detail Nylon. If you join the wheels in a strip the cost is very reasonable. I have engines running with wheels printed by Shapeways over three years ago and they are as true today as the day I fitted them. However, I am not an expert at resin printing, I am sure that others have had better experiences. Edited March 12, 2023 by Timber Link to post Share on other sites More sharing options...
apl31 Posted March 13, 2023 Share Posted March 13, 2023 Excellent, thanks for access to stl file, those are going to come in very useful for future projects. Out of interest is it easy for you to produce stl for a plain wheel without any crank for 5ft 6in wheel? Another future project. Link to post Share on other sites More sharing options...
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