Wednesday, 19 August 2015


As you know, in the middle of last week I ordered the metal that I intend to use as the basis for the tube bundle thrust chamber.

The 316L tube and hollow bar arrived today. The hollow bar came from Schoeller Bleckmann in Oldbury and the tube from Steel Express in Wolverhampton. I also ordered a piece of 316L plate. This didn't arrive today so I will have to chase it up tomorrow.

The hollow bar is 212mm OD x 170mm ID. Here is a photograph of it sitting in it's protective sack. It was too heavy to lift out...

This has to go in the lathe somehow. My current thinking is to drill and tap the piece and then bolt it directly to the faceplate.

Here is the 316L tube, it is 10mm OD x 2mm wall:-

These tubes will need to be cut into near enough identical lengths. I have decided to make a cutting jig based around an angle grinder to do this.

The jig will be composed of a section of aluminium angle welded to an aluminium plate. This angle will act as a sort of V block to hold the tube being cut. Sections of  drilled and tapped aluminium flat bar will be welded on to the angle to form a clamping feature. The angle grinder will then be mounted on a pivoted bracket, enabling repeatable cut off to be achieved.

Here is the base plate of the jig:-

This picture shows the angle with a piece of flat bar showing how this will be mounted to form a clamp:-

I milled the flat bar sections square - not strictly necessary but it made me feel better:-

Here is a final shot of the angle and plate trialled up with a scrap piece of angle to show the position of the angle grinder bracket:-

I will also have to make a tube bending jig, so there will be plenty of practical updates over the next few weeks. Once the jigs are made, I can trial the actual tube fabrication process.

Keep watching.


  1. I can't help but think purchasing a chop saw and then selling it afterwards would be easier...

    I bought a 14in one which is awesome for tubing but for little tubes like that a 6in one would be fine, eg ebay item 291052906115 for £70

  2. Thank you very much for commenting David. I thought about buying a chop saw, but I have the time and the just thought I'd make one. That said I will look into the tool you suggest, thanks again.