-missy-

Hello. In the fantastic article by Trevor Hughes on Talyllyn Wagons he mentions using a form tool from a company called carbide solutions. I have searched for the company online but sadly havent found anything listing form tools. Can anyone point me in the right direction to the company? Thanks M.

Some people like to use nothing but 2 flute 'slot drills' saying they cut better. J.

Hi Valentin. I think its one of those things that comes with experience. There are many options to choose from, here are some of the methods I use... 1. I now use pretty much exclusively Carbide cutters, mainly from here https://www.shop-apt.co.uk/carbide-end-mills.html They are cheap and cut nearly everything you will need to cut. Check the shank diameter though as its important they fit your machine. I never buy just s single cutter in any size, I normally get at least 2 just in case one breaks. 2. Most standard cutters are designed to cut upto 2x the diameter of the cutter depth, your can get 'long reach' cutters if you need to go deeper but they are obviously more fragile so you need to reduce the depth of cut and / or feed rate to suit. 2. Cutters are pretty robust too, you can tell how hard to push them by how the machine sounds, if the machine is struggling then back off the feed / depth of cut. I don't normally worry about spindle speed and feed rates, you can calculate them but I just listen to the machine, you can tell if you are working a milling cutter to hard. 3. The diameter of the cutter is normally dictated by the minimum radius and / or diameter of hole I need, I always aim for a largest cutter I can get away with as these are much more robust.. To compensate for this I always aim for a cutting depth of around 1/3 to 1/2 (at a push) the diameter of the cutter when cutting the full width of the cutter. 4. As Rich says, try to avoid cutters that don't centre cut. These days its not exclusively 2 flute cutters, many smaller 3 and 4 flute cutters can cut the full width of the cutter too. It means you can 'plunge cut' meaning treat it like a drill. 5. Practice, practice, practice! Julia

IM pretty sure you can add the cost of resin into the slicer and it calculated the cost per print based upon the volume? The valuable part is the stl file (and the generation of it). I would be very happy to print some of those off myself! J.

I think there is some potential in a wagon body like that, the livery options are endless. Having the possibility to easily put together a rake of these wagons is so tempting. You must do a 5 plank one too. To answer your question, its personal choice. There are some who like to be as scale as possible, there are others that like a bit of detail. I personally fall into the latter, I love seeing a bit of detail, even if it is slightly exaggerated. J.

That's a really good question! I haven't found anything that defines exactly how much you should pre-load a backlash nut. I therefore assume its very dependant upon what type, its installation, and how its being used. The way I did mine was to start with the maximum pre-load then back them off until things started to work comfortably. I found that when I set them to the maximum pre-load, the stepper motors couldn't turn the leadscrews on my machine. Julia.

Eliminating backlash on any CNC machine is important. I couldn't tackle things like below on a machine with backlash. Julia.

Hi All. I have a GWR China Clay wagon ready to go if anyone is interested? It fits a 2mmSA chassis although I cannot remember which one! Usual disclaimers, only for personal use, etc, etc... Julia

Hi Justin. These might be adaptable if you can find a set... http://www.tpmodels.co.uk/1820.html Julia.

Hi. I think what the Stationmaster is trying to say is this.... I really like the "What RMweb really needs is to get shot of the idiopt profanity filter and introduce a proper dumbo filter which automatically rejects nonsense on a sort of 'three strikes and you're out' (for ever) basis but that would need an awful lot of AI to make the system do it instead of humans intervening. " comment. M.

Hi Izzy. I seem to get mixed messages regarding that. Some say you can and others not. My theory was to try it and see! http://modelenginenews.altervista.org/techniques/skews.html Plenty of places around like this if you are prepared to take the risk https://www.aliexpress.com/item/32508729832.html?spm=a2g0o.productlist.0.0.2d4d2a35zkQ3YP&algo_pvid=4073d1ab-5dc0-41ef-baef-5b58a7c18718&algo_expid=4073d1ab-5dc0-41ef-baef-5b58a7c18718-19&btsid=2100bb4c16031810784491686e838f&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_ Julia.

Hi Izzy. I am designing the machine as a stand-alone so its not reliant upon a mill or similar, which would make the control harder to work out with retro fitting etc (as you probably know). The cutter spindle bit is still being designed by myself. The intention is to build in the ability to angle the cutter upto 30 degrees which should allow the cut skew gears for worm drives (but not quite enough for bevel type gears). There is a source of gear hobs from China so I have one already (0.2Mod) to setup the machine. If it works then no doubt this can be swapped out for others. Julia.

Apologies Izzy. It's a machine to (hopefully) enable me to cut my own gears. It will use a gear hob instead of involute cutters. Julia.

Thank you Jan. The parts were printed on a FDM machine. It makes producing parts for these mods so easy! https://www.prusa3d.com/original-prusa-mini/ I haven't had to do anything other than ream out (by hand) a couple of holes on some of the parts. So far it looks like it is going together really well (there is still quite a bit to do) but I will use a DTI once complete to check the critical dimensions. Julia.

Hi Mike. The only options I can think of are to either replace the speed control for something a bit more flexible for driving the motor or fitting some sort of gearbox like the USOVO planetary gearbox. Julia.

Mini Hob is progressing... J.

Would something like this help? https://www.axminstertools.com/skill-centre/engineering-courses Julia. This should be in the jigs and tools thread....

Hi. If I had realised you posted the same question in this thread I wouldn't have bothered replying to your PM and posted here instead! I would very happily find a home for that lathe! Julia :p

You will be telling me next you have never popped into a supermarket to use the loo or parked in one of their carparks while getting some fish and chips next door? M.

Hi. I'm might be missing something but there are plenty of browsers around with quite robust ad blockers built in, free to download, etc. I never have any problems with pesky ads anymore. Missy.

Hi Mike. You can but it will cost you lots of money! Julia.

Hi. Its not what I would class as an easy mod. You have to make a few bits... The original setup uses a splined socket which the motor locates into (red). As I was replacing the motor, I had to make a shaft to suit. Fortunately at the end of the original shaft, there is a M6 thread so I made the replacement shaft screw into that. I also designed and made a plate (3DP) that sits onto of the original housing, this was designed to mount the new motor along with a top bearing for the new longer splindle shaft. Choosing a brushless motor is a bit of a minefield as there are so many variations. In the end I went for this one as it meant I could use a 12v 20A power supply. https://www.componentshop.co.uk/lc2835-9t-900kv-outrunner-brushless-motor-leopard-hobby.html The motor is mounted inside the original Proxxon housing and it drives the spindle through a 3:1 belt reduction along with the ESC controller for the motor and a repackaged servo tester which is used as a speed controller. As I mentioned, it is not an easy mod but it is so worth it. The new brushless motor is significantly quieter and along with the speed control and belt drive reduction, I can now run the machine at more sensible speeds. Julia.

Hi Rich. The original uses plain bushes (blue) and some steel profiled plates (red) on the ends, I replaced these with some profiled Brass plates with a way of mounting some thrust bearings (2 on each axis). As for the area where the leadscrew nuts live, I basically chopped out the mounts for the nuts and replaced them with some brackets made from Aluminium allowing for some adjustment to make sure there was plenty of opportunities to make sure things aligned well. It seems to work well. Julia.

That's weird, I got asked the same question too. My spindle runout is around 0.02mm, I would be very happy to use it if it was 0.002", you will be hard pushed to get a machine spindle of this type to run any better really, that is more than adequate for our stuff. I sourced mine from China. It was a 6mm OD x 1mm pitch 'trapezoidal thread'. Flanged nuts do exist for them but I haven't seen any anti-backlash types yet. I ended up chopping up a couple of the flanged nuts to make a single anti-backlash type. They aren't expensive. Julia

Hi Bill. I did consider trying one of those gearboxes out but one of my requirements was to try and reduce the noise the machine makes when running. I thought that the noisy brushed motor plus a metal gearbox would make the noise even worse. Its a big reason why I decided to go for a nice quiet brushless motor and belt drive. I don't have any doubt the gearbox will help and fit the machine well. Usovo seem to make good quality stuff. The machine does run far too fast so slowing it down does help lots. Julia.