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Member postings for Roger B

Here is a list of all the postings Roger B has made in our forums. Click on a thread name to jump to the thread.

Thread: hobbymat milling machine
18/01/2021 13:06:06

This is the clamping screw:

clamping screw.jpg

Thread: Bowman 'O' Gauge Model Steam locomotive
15/01/2021 14:48:59

There are quite a few pictures on here which may help you to identify what you had:


My brother has a tender locomotive and I have a stationary engine.

004 bowman steam engine.jpg

005 bowman steam engine.jpg

Thread: oversize ER16 collets
14/01/2021 17:19:54

These people have them, but I don't know if they can deliver to the UK at the moment.

Thread: Wallaby crankshaft
13/01/2021 14:27:25

The first question I would ask is what are you going to do with the engine? If it is going to idle for a few hours a year at a show mild steel will be fine. If you are going to haul passengers with it in an 1831 every other weekend then you will need to use something better.

Thread: STAR Hit & Miss Engine
10/12/2020 14:53:58

Splendid job yes yes

There was some discussion about this on another forum. The key points for good hit and miss operation were low friction and the quality of the firing stroke, a good hit is required. You may need to experiment with the mixture and timing to find an optimum. If you can apply a load to the engine to keep it below the governor speed adjustment may be easier.

Thread: Mc Donald Model tractor
04/12/2020 11:21:17

Thank you smiley This is my first go at a two stroke and bought a number of challenges. The prototype has angled ports, drawing these and the susequent maching was interesting. I strarted with an aluminium piece with the same dimensions as the cylinder but much shorter. This gave me a chance to see what was going on and reduced the amount of scrap. Using small long series milling cutters results in some deflection.

090 compared to the exhaust ports.jpg

I cheated with the reed valves and bought a comercial set (spare part for a scooter, less than £2) which fitted in the space that I had.

252 possible fit 1.jpg

I initially ran the engine as a spark ignition petrol engine to confirm that the red valves and ports actually worked.

510 set up for trials 2.jpg

Lots of fun laugh

02/12/2020 11:51:14

Very impressive work on the gearbox yes yesyes

There seem to be very few people building land vehicles powered by self built engines. There are a lot of ETW Wallabies out there but very few 1831s. I have seen a number of Lanz Bulldog derivatives. I think someone makes casting sets.

I am working (very slowly) on a couple of models. One will be powered by a 12cc four stroke twin. I have almost got the engine running to my satisfaction with a constatnt depression carb. The simple carbs tended to struggle when a load was applied. This will be a freelance design.


The engine on it's test bed

716 improved cooling pipe layout.jpg

The second one is based on the Field Marshall horizontal single cylinder two stroke diesel. I am slill learning/experimenting with the injection system. I have acheived some firing but not sustained running.

655 new pump fitted for the first trials.jpg

Thread: Proxxon mf70 spindel/motor coupling?, any good idears?
24/11/2020 09:20:37

There appears to have been at least 3 different designs of coupling used. I found this company when looking to upgrade my MF70 to ER 11 collets. I decided that the price was a bit high and instead I may purchase a plain shank ER11 chuck and machine the top to take the Proxxon coupling.


What is your coupling like? This is mine:

005 drive motor and speed control board.jpg

006 spindle drive coupling.jpg

Thread: Proxxon collet size?
28/08/2020 14:45:43

In an attempt to add more confusion. The FF/PF 400 (FF was freestanding, PF mounted on the back of the PD 400 lathe) appear to have had two types of collet. The early one looks a bit like an OZ but I think was a Proxxon own design is shown here as part number 24252.


The later machines used normal ER20 collets. The changeover from the old style is mention at the bottom of this site:


A German owner of an older PF 400 ordered the newer ER20 spindle from Proxxon complete with bearings and tolerance washers for around €100 (in german).


The Proxxon spares site (in english) is here:



Thread: Australian diesel loco in 5 gauge.
31/07/2020 07:11:22

That's an impressive engine. Did you run it much? Is that a fuel or oil pump next to the carb? Is the camshaft chain or gear driven?

28/07/2020 10:44:38

Excellent, One of the rather rare IC locomotives powered by a home built engine.

Thread: Mc Donald Model tractor
23/07/2020 11:19:10

Thank you. I have seen your video on YouTube.

I am also working (slowly) on a 20cc two stroke full diesel based loosely on the Field Marshal layout. The details are on MEM:



Best regards


22/07/2020 11:09:32

Is your Lister the 6/1 that was serialised in ME?

21/07/2020 15:24:27

Interesting If I am reading under the radiator correctly it's an Australian maker. I thought that the single cylinder hot bulb/semi diesels were a European thing.

Do you have thoughts for the injection system yet?

Best regards


Thread: Spark plug lead
07/07/2020 08:10:10

You shouldn't have a problem joining the plug leads, but leave as much of the old lead as you can in case you have to remake the joint later.

I have made clips for that type of plug from phosphor bronze sheet that retains it's spring.

556 filing to shape.jpg

Thread: 2mm endmill help
02/07/2020 07:07:06

I also have an MF70 and decided to check the play and runnout. Measuring on the shank of a 3mm endmill I got a play of around 0.02mm and runout of around 0.04mm.


So far I have only broken one 1mm end mill when cutting a keyway in a silver steel shaft. This was mostly my fault. The first cut just put a flat on the shaft and the second cut was a full slot and was too much with the depth of cut I had chosen. Reducing the depth of cut resolved the problem.

Thread: Floating Reamer Holder
22/06/2020 14:01:21

I have an Angst floating reamer holder like this:


It has an adjustable centering spring to control 'droop' when used in a turret/automatic machine.

Thread: Material for engine block.
10/06/2020 07:28:40

I have used this material, EN AW-2007 AL CU Mg Pb F37, for crankcases and cylinder blocks. It is available up to 40mm square in 200mm lengths. It's a German company and appears to offer shipping to the UK for €6.99.


I don't know how the prices will compare to UK suppliers.

It turns well with specific inserts for aluminium. I have used threads down to M1.4.

Thread: HobbyMat Lathe
04/06/2020 11:24:06

Difficult to say exactly what is going on. There should be a thrust race (33) and a collar (8) held in place with a taper pin. This locates the headstock end of the leadscrew. The tailstock end is located by the hand wheel. There is a simple dog clutch to connect the change gears.

hobbymat leadscrew.jpg

Best regards


Thread: Hobbymat top slide repair
02/06/2020 10:18:13

This user has had a similar problem:



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