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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: will it,won’t it
07/02/2018 08:30:18

Jason, do you know of any video clips or details of running rollers? I can find ones of the engine alone but not a complete on.

If I ever get my diesel to run I intend to build it into a tractor using similar dimensions and drive to the ETW roller.

Thread: In-line Diesel Engine Model
19/01/2018 07:43:32

Going back to the original question:

How big is the engine going to be? The one in the video is around 30mm bore and 38mm stroke. (it wasn't built by George Punter, but by W7CS. It's just liked on George's YouTube).

The horizontal valves suggest that the engine you want to build has a clearstory combustion chamber which should make things a little easier.

The injection pump on the engine in the video is ~4mm bore and ~2mm stroke. This seems rather big unless he is allowing for a lot of leakage. Injection pressure is ~80Bar which is the range I am trying to achieve.

If you go ahead with this I would suggest that you make a bar stock single cylinder version to learn and experiment on.

Best regards


Thread: Balacing a locomotive power unit
15/01/2018 19:38:35

This was one of the major problems with conventional steam locomotives. The various out of balance forces used to cause significant damage to the permanent way. The introduction of diesel and electric locomotives greatly reduced the damage and allowed greater axle weights and power outputs.

Thread: In-line Diesel Engine Model
15/01/2018 14:41:59

Howard, I felt that trying to produce a multi hole injector in this size would be extremely difficult and at a high risk of getting blocked. I am using a pintle type with a hole of 0.35mm which appears to give god atomisation at around 60 Bar. The other consideration is that the combustion chamber will be smaller so less penetration will be required. I doo have a concern that the fuel will just end up on top of the piston.


15/01/2018 11:13:32

I am very slowly developing a high pressure injection system for cylinders of around 20-25cc. The injection pump bore is 2mm as is the maximum working stroke. The injector needle is 1.5mm diameter.

The system has operated on petrol as a manifold injection system and trials using alcohol (less smelly than petrol and diesel) have reached pressures of around 60 Bar.

The details are in a thread on MEM:


I believe that you need to be a member to see the pictures.

Thread: using an inverter to power a 3ph hoist
04/12/2017 11:20:32

The area I would look at is the brake. If it is entirely mechanical no problem. If it is spring apply electric release it should be ok but probably wouldn't allow for variable speed/ramping.

Thread: Combined Lathe & Mill
23/11/2017 11:39:10

I started out milling with a vertical slide on the lathe. This worked but travel was limited and setting up was not aided by gravity. Like you I do not have space for a separate mill so I added a milling head. This is certainly a compromise and is not as rigid as a true milling machine, but by removing the lathe chuck and tailstock it has quite reasonable travel for my use. An up to date Hobbymat and TECO mill are available from Pro Machine Tools.

Best regards


12 in place.jpg

Thread: My first lathe
04/10/2017 11:11:00

The first lathe decision is always difficult.

Buy the biggest/best you can afford is one way of looking at it.

The other thought is buy something that will be sufficient for what you want to start with. If it is not too expensive it won't hurt so much the first time you take a lump out of the bed or cross slide crying You will also have money available for tooling, it's quite easy to spend the same as you spent on the basic lathe. As you gain experience you can then see what features you really need and select another machine that has these. Some of the tooling will be transferable to the new lathe so it won't be like starting from scratch again.

Best regards


04/10/2017 07:23:31

I started out with one of the generic minilathes and latter added a milling slide designed for the smaller Clarke lathe by drilling and tapping 4 holes in the cross slide. There are a couple of pictures in my album milling slide.

What are you intending to make on this lathe?

Best regards


Thread: Warco or Hobbymat MD65
27/09/2017 07:13:05

I started out with an Einhell Minilathe and then moved on to a Hobbymat with milling head.

The Hobbymat is more rigid and better finished but is slightly smaller. The headstock is MT2 and around 12mm bore. The Minilathe has MT3 and around 19mm bore. The low speed kit for the Hobbymat is still available but the tumbler reverse if you want it would have to be found secondhand. Other accessories may also be harder to find.

What are you intending to make, this my help guide your decision?$

Best regards


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