Jan W

5 hours ago, Enterprisingwestern said:

 

Whilst the method previously mentioned is obviously successful, is there a simpler, less engineeringly complicated way to put a decent motor in the MF70, or at least some way to control the speed of the thing?

 

Mike.

Here is a link how to reduce the speed of the MF70 adapting the original controller board:

https://www.instructables.com/Reducing-the-Speed-of-the-PROXXON-MF-70/

8 hours ago, Lacathedrale said:

I think one of my options is to check out the ER20 collet chuck from there, but I guess I need to figure out exactly what I'd be doing.

You don't need collets to machine wheels. It's just quicker if hou have to do many (and of different sizes).

I usually chuck a piece of plastic rod, face it square and bore a hole in which the wheels are a press fit.

Chamfer the inside corner of the hole with a countersink so the radius of the flange doesn't sit against the plastic.

Use the tailstock center to press the wheel against the plastic, if necessary with a piece of rod between the center and the wheel if the center doesn't reach the wheel.

This gives a 100% true running setup without any chance of the chuck marking the thread.

Remove the wheel from the mandrel with your fingernails behind the flange or with a wooden or plastic rod through the spindle bore.

Of course you will need a collet if you want to machine the wheel face but then a small size collet is all you need.

Jan

I switched from a Sieg lathe to a Taig (Peatol in the UK) and the Taig is much more refined (except for the large AC motor).

The Sieg lathes are a bit rough but work fine. I had a smallish one, the C1.

After a few years I replaced the spindle bearings with bearings from Arc eurotrade which were a huge  improvement. 

I was not happy with how the tailstock was made, the barrel was a bit sloppy in the tailstock casting and there is no proper solution to prevent it from turning. The clamping screw runs in the keyway and that is it.

Impossible to use with small drills, in the end I added an extra toolpost to the cross slide and mounted a small drill chuck on the second toolpost.

ER collet chucks for the Unimat are available from RC machines in Luxemburg:

https://www.rcm-machines.com/en/search?sSearch=collet%2Bchuck%2Bm12&p=1

There's a prototype for everything....

Edit: what happend to the buffer of this wagon? It would not be used in regular traffic like this I think?

There's even a picture of the Aerofilms De Havilland with photographers:

https://artsandculture.google.com/asset/francis-lewis-wills-jerry-shaw-and-claude-friese-greene-in-a-dh98-biplane-aerofilms-ltd/kAH9r_6ojIczUQ

Rumpler would be for the gloat box of coarse 

Could this be something? Bit too large but maybe acceptabele.

https://www.emodels.co.uk/valom-1-144-bristol-f-2b-fighter-vs-rumpler-c-iv-14422.html

https://en.m.wikipedia.org/wiki/Bristol_F.2_Fighter

Jan

Guy,

I've edited my post to add an important step.

And I'm very happy with this little lathe. I started with a Chinese lathe which worked ok but the Taig is much nicer!

20 hours ago, Nigelcliffe said:

 

So the wheel sounds like it is similar to the 03/04 diesel shunter.

 

I'd make a chuck which locates the wheel on the bore (insulation pushed out), but clamps the wheel at/near the rim.  So, any turning pressure is only in the rim area.   Something like this is pretty quick to make and hold in a collet chuck.  Left part cylindrical, with axle to slide into wheel, threaded at end to take clamping nut.  Middle is clamping plate with hole through centre.  Right is clamping nut to engage on thread (washer optional).  Exact dimensions depends on wheel in question.  

 

 

 

This is exactly how I replaced the rims on my Dapol Terrier, altough I used the tailstock to press the wheel against the mandrel.

This is my Taig lathe with the tools I made up to hold the wheel. A mandrel with a spigot which is a sliding fit for the wheel. No damage to the axle hole because no pressure is needed to push the wheel on. End of the spigot is turned down to 1mm and fits in the part that presses against the wheel.

The first red arrow points to a plastikard disk with 400 grid abrasive paper to transfer the lathe power to the wheel. Hole is large enough to clear the inside of the wheel boss.

The other arrow points to the part that presses the wheel against the mandrel. 1mm hole to engage with the spigot and a shallow larger hole to clear the front of the wheel boss and only apply pressure to the outside of the wheel.

Step 2: wheel placed on mandrel (with plastikard disk behind it)

Step 3: turning down the rim. New rim is placed on the pressure part so it is easy to test the fit without disturbing the setup.

Step 4: turn a 0.25mm deep recess to clear the front of the new rim. Outside diameter of the pressure part is the same as the inside of the new rim so the depth of cut is reached when the tip of the tool touches the pressure part. This is quite important because the new rim can be pressed against it and will run true.

You can just see it in the view below.

The three stages. 

Unfortunately I can't remember how I turned down the back of the wheel. I think I used a piece of plastic turned square with a hole in it for the wheel rim. Push fit and the wheel supported by the tailstock to prevent it from working loose. Very light cuts until you reach the new rim.

Jan

Simon,

Without the coupling rods it shouldn't be difficult to find the tight spot.

Just turn the worm one revolution at a time and repeat that 30 times (on a 30:1 work that is).

In every position rotate the wheel slightly forward and backwards, without force that is.

There should always be a bit of play between the teeth of the gears and with this method  you can see that for every position of the gears. Check the spur gears and the worm gear of course...

Jan

I never built one but it seems to me that the pegged easitrac turnouts (shop item 1-401 etc.) with milled crossing will be by far the most forgiving option.

I've built copperclad and 'normal' easitrac turnouts and the latter run very smooth.

Disclaimer: the easitrac were also my most recent turnouts so I had more experience...

Jan

21 hours ago, Izzy said:

The level crossing.

 

I thought I should just explain the forward diode voltage issue I had for anyone interested. The motor used was a Mitsumi which is fairly slow running and the total gear reduction involved is 456-1. Here is a shot of the setup. The gears are old Airfix/MRRC 64dp ones I’ve had for, well, decades. They were originally meant for use in slot racing cars, which I played around with back in the day.

 

 

The one on the main shaft is 48t and driven by a 12t on the next shaft. This is attached to a 36t which is again driven by another 12t. This is mated with an old Gibson 38-1 100dp wormwheel while the worm is one of the 2mmSA’s black 100dp worms cut to half it’s length.

 

Even with this reduction the motor only needs to turn over very slowly. With hindsight - a wonderful thing - I should have added another reduction stage. My feeling is that somewhere between 900 /1200-1 would be a better reduction, to allow the motor to spin faster at the slowest disc rotation speed needed. Especially for use with plain/simple DC.

 

But anyway, at the reduction used not much voltage to power the motor was needed, and when the diodes that allow the motor to be reversed kicked in they dropped the voltage to below that which allowed the motor to turn over. Increasing the voltage to compensate meant that when they were bypassed the motor speed jumped up too much. I used IN4001’s which I think drop 0.7v. The easy answer has been kindly posted, add diodes the other way to balance things out, but of course not being that bright that didn’t occur to me!

 

Izzy

 

 

I think that your solution with a decoder is much better because it gives the motor more torque at such a low speed.

22 hours ago, Izzy said:

 

I had intended to run it off DC as per his but ran into diode forward  voltage drop issues which using a decoder via DCC has helped overcome.

 

Your remark made me wonder if this could be solved easily on DC and it can. Just add an extra diode and connect the microswitch like this:

If voltage drop over the end switch was your problem of course.....

6 hours ago, Chris Higgs said:

A case of needing  "right material, right place" 

Thanks Chris and Jim!

I didn't think of the brittleness of the resin but something in the back of my head kept telling me that it would be difficult to remove the printed frames from the support without breaking them.

I'll look into the possibilities of laser cutting in card:

https://snijlab.nl/en/m/196/resinboard-0-5mm

Jan

Would it be possible to print window frames and doors for buildings etc?

I'm scratchbuilding a station building and railway pub and of course I also have to make the windows and doors.

There are possibly better options for windows like etching, laser cutting or even a craft robot but if a Photon printer can also be used for it that would open lots of other possibilities like coach roofs, loco parts, etc. 

I have had some of my own designs (platform edging, foundation and walls of another station building) printed by Shapeways already but that's quite expensive.

The reason for asking this is that I always see a relatively large base for the prints and I was wondering if such a base with supports could also hold a delicate window frame.

Jan

57 minutes ago, Lacathedrale said:

 

Question though - how would a loaded P.O. coal wagon (i.e. loose) be unloaded into sacks at a siding where there was no staithe to shovel into? Surely it wouldn't be bagged in-situ?

I found some interesting images:

https://www.gettyimages.nl/detail/nieuwsfoto's/privately-owned-railway-wagon-1938-workers-unloading-coal-nieuwsfotos/90747028

https://nl.pinterest.com/pin/339881103121045221/

https://www.warwickshirerailways.com/gwr/gwrc3.htm

Would it be an idea to leave the layout as it is and then add a removable side at the 60cm position.

You only have to move the small building on the front a bit to the right.

Looks less cramped than your mockup with the turnout moved to the siding I think.

The DLJC rules only restrict the dimensions of the scenic area but you're free to do what you want with the offstage area.

And of course you have to cover the front on the left side but it must be possible I think.

Jan

Maybe it's better to just wait and see what happens. It could be wise not to book your layout to a 2021 overseas show until everything is clear.

I'm glad I can still bring the little layout I'm working on to the DJLC in June!

Jan

Maybe this could be useful if someone is looking for an affordable and small blasting cabinet:

https://www.hbm-machines.com/producten/straalcabines/straalcabinessub/hbm-sbc-90-straalcabine-zwart

Haven't found anything comparable on UK sites.

Website is in Dutch and it seems there is no option to change language. If in doubt please ask :-)

Jan

On 21/01/2020 at 18:36, brossard said:

Glass fiber brushes can be horrid but I wouldn't be without mine.

 

 

I always use a track rubber for cleaning before soldering.

Easier to clean than these loose fibres.

I don't use it to clean my track though.....

Thanks!

I noticed it was solid but it was hard to tell what material. Could also have been a softer material like sundeala.

I've built up my platform from styrene but I'll make some test pieces from card to see if I can get something similar.

What did you use for the platform surface? Looks very good!

Jan

How would a muff/axle oscillate even if is not cut off square?

If the bearing flanges are flat against the frames the axle with muff will not oscillate.

It's just that one spot on the muff makes contact with the bearing face and that's all that happens.

If you however use Simpson springs things are different and care must be taken that the muff ends are smooth. 

Looking at this setup it seems to me that the worm itself is long enough to bridge the gap between the motor and the bearing in the gearbox.

If it is long enough you can mount the worm on the motor shaft with the adaptor sleeve and insert a piece of 1.5mm axle steel in the other side of the worm. This will then run in the bearing.

Jan

I would think that it is the coal space door, similar to the one on this B16 tender:

http://www.railway-models-and-art.co.uk/blog/?m=201705

Edit: but why two? maybe I'm wrong...

Edit 2: this link seems to confirm my first thought:

And did you find the SER kits instructions for their 7mm scale model? Lots of information there:

https://serkits.com/catalogue-and-ordering/downloads/

The O class is on my to-do list for my DLJC layout, I also have the Worsley works etches.

Jan