@ColinG You’re on the money with the “Mark 2”. You’ve done a grand job with the tools you have, well done. Cheers Pete
This is my case hardening compound I created from a recipe I found online. It's basically charcoal - 90% and sodium bicarbonate - 10% crushed and mixed to a granular texture. Inside the tube is the main steel component with the compound packed in around it. I now need to either have a bonfire in the garden or light our wood burning stove to cook it for an hour or two but it's so bloody hot and humid here in Scotland I don't really want to! I'm not sure I can reach the temperatures required but I'll have a go.
You should end up with a nice colour case hardened finish with that method. You could just heat up the tip with a blowtorch and dip the cherry red metal into the compound for or five times and then quench it at the end.
Exactly what I did and here's the result... I'm waiting for a new check valve to arrive before I reassemble the 220 and get it working again. Here's what's left of the tube..
Update 3 (guess what I've been up to most of today!) As @ROBBO55 commented, there needs to be a method of holding the tool in line with the pump tube. He mentioned a plastic sleeve but I couldn't find what I was looking for so I improvised with a copper end cap - again! These things are blooming useful I have to say! It was a little too small so I relieved it with a metal bar and a hammer and then cut it down a little. With a 12mm hole it now fits on the pump tube snugly and supports the CV tool as it does it's job! I think that's it now, I just have to be patient and wait for the check valve to come so I can try it out. I suppose I could have bought a tool and saved myself the effort but where's the fun in that! P.S. The tool shaft spent roughly 3 hours in the fire work-hardening at roughly 1100°C or at least, thats what wood fires reach when burning hardwood.
Ha ha, I think this will be the only ever version! If I had access to a milling machine I might consider making more but as it stands there's too much hand work involved.
** Update ** My original check valve removal tool was made for the old style version so I needed make a new central rod for the new, smaller style CV with a 3/16 32tpi thread. The first problem was... finding the right type of 3/16 32tpi thread as there are 3 at least: NF #10 32, 3/16 32 ME and BSF 3/16. What I ended up with (purely through random luck) was a BSF 3/16 die... but thank goodness, it fitted! I used it the moment I'd finished and it performed perfectly.
This is an old discussion, but I hope someone from experienced people will read my questions. As I understand the internal thread of the valve: BSF 3/16-32 (Coleman 226A700E) Correct? The diameter of the valve head is about 12mm, what is the width and depth of the groove on the valve?
The BSF 3/16 x 32 thread is very close but maybe not perfect. The BSF has a Witworth tooth profile of 55° but the National Fine 3/16“ has a 60° profile which i believe will fit better. I had to use the grub screws on the die stock to tighten down the thread i was cutting. This cut a slightly smaller overall diamater thread which probably confirms my suspicions. If you have a choice, I would suggest you use use the NF 3/16" 32. The width/depth of the groove is 3.1mm wide x 2.6mm deep as far as I can judge. These are most likely the closest to an imperial measurement. Hope this helps.
