Member postings for Nick Welburn

Interesting, yes I’m talking about the eccentric straps. I’ve been milling every face. Of which there are many, when it seems I should have faced each side in the lathe and filed to shape. That in retrospect might well be easier!

Working on the eccentrics for Minnie. I’ve been end milling the faces and then boring the centre. It’s working OK. But the metal is a bit smeary and I am sometimes getting so variation in levels with passes over the surface.

Wondering if I perhaps should be flycutting the big faces? Would that give a better finish?
move got a boring head. Could I effectively fly cut with that?

Interesting, mines a type 4 2.0l but I suspect the issue is the same

It’s lightly spring loaded to hold position on the rocker arm. Because the tip is chewed up it’s pushing the rocker across as you preload it. Hence the desire to clean it up.

Hi Dave,

They generally are, and VW described them as such. The reality is though they need a tickle here and there. I had one that had unwound so I’ve started a reset.

From what I’ve found they seem to have had a hard life and I can’t get the preload on as they slide off the valve tip from the wear (hammer!) patterns

Well mostly because 8 x £5 = £40. I’ll have a play suspect I’ll end up ordering a set

The heads of the tappet screws on my VW baywindow with hydraulic lifters are some what hammered and won’t easily adjust.
I could replace at £5 each… or a could give them a spin in the lathe… any downside ?

Right then. I’ve got a new casting for the cylinder. Starting to think about how to tackle it.

I think I need to machine two reference surfaces one on the top and one perpendicular to that.
These will act as reference surfaces to allow me to set up to bore the cylinder and the mounting surface.

Thoughts?

I've found copper hard to part off, its really soft and kinda gummy so a dig in seems to end badly. When I did the shell for my Cringle boiler I resorted to making a delrin mandrel for it and going through.

Awesome thanks Jason. I do wonder how I’d have managed to make anything without your sage advice. I’ll get some ceramic board to insulate the water pump. I’m also going to hide a manual one on the side of the tender as well. I want this thing to be useable

i was a bit nervous about getting this built, it’s starting to seem achievable. It’s just like a Stuart but with more bits and actually a chunk of the dimensions are non critical.

Good progress today, started to get the water pump together, I think this is probably more complex than anything I've tried on a Stuart engine with multiple surfaces to machine and multiple interlinked passages internally.

I've got the bones of it sorted. Needed to order a few extra 40tpi taps and dies, and a reamer set. They should arrive from Tracy next week.

I hear from what I read that the water pump on Minnie tends not to be effective. I don't quite understand this as to why, are there any obvious mod's I should make? All I can imagine is that its prone to air locking? Does need additional bleed ports in the caps? say a 10BA set screw or similar?

The gland nut has a bizarre dimension on it that I don't understand. Its a 0.384", thats not obviously metric or imperial? why the random size?

Could well be linked to the next question... where is a good source of 'O' rings? I'll need them for the piston and the pump.

Ordered a new one, instead of trying to sort out someone else's mistakes I can start on my own.

Went for one from GSS model supplies as it was a solid £25 cheaper than the AJ reeves one. Wonder if its just markup or if there is a difference in casting quality? Time will tell!

Right I've had play. Have I trashed the part, maybe....

So my challenge was broadly the radius under the cylinder casting was not the same radius as the boiler. In addition, the faces on the cylinder were not perpendicular to each other.

I chose a register plane, and pulled that straight. I've then machined the faces of cylinder to parallel / perpendicular.

I've also used a boring head to re-cut the curved face. This sits nicely. on the boiler now, it it isn't parallel to the top surface.

I could put a fresh cut over it, but how thin is too thin in the casting over the boiler? its sitting at around 4mm, so I could correct it, then I'd be at perhaps 2.5mm? is that too thin for a viable gun metal casting? I've then got to sort out the fact that the machined bore is likely no longer in register to the new outer faces..

Should I just spring for a fresh casting?

Hi Jason,

The cylinder was part machined when the project was abandoned by the previous owner.I have no idea how but the finish isn’t great.
My lathe doesn’t have a slotted cross slide. It’s an Amadeal 7*14 cj18b not a big machine. Thankfully the material machines easily, I think it’s a gun metal casting.

I’ll have a look at a between centres approach but I can’t immediately see how it could work.

Got started tonight. Had a look at the cylinder casting, lots of surfaces out of parallel. So I’ve set a new reference surface up and started to pull it together.

Now the bottom of the casting has been machined, but it rocks on the boiler so it’s clearly not concentric.

it’ll need a recut to put it right. I’m thinking could use my boring head to do an interrupted cut down that’s parallel ti the new reference surface.

Any thoughts?

I’m progressing slowly with my machining. Generally now I get the holes where they are meant to be and straight… dimensions are good.
but I struggle with getting a tap in straight. Leading to wonky studs and such like.
I use a little tapping fluid. But there must be a knack or a trick to getting a tap to thread in straight.
I have a tap handle. I have taps.
what should i do or watch?

Apologies, poor English on my part. I was cautioning against climb milling. I was completely unaware of the concept until I’d destroyed a couple of cutters and parts.

Something that was lost on me as a newbie was the direction of the milling is key, have a read about climb milling, its makes a heck of a difference to the outcome for me.

Surely there is a simple answer? is it a pineapple twist roller?https://www.bing.com/videos/search?q=pineapple+twist+blacksmithing&qpvt=pineapple+twist+blacksmithing&FORM=VDRE

Edited By Nick Welburn on 14/03/2022 14:25:51

I’ve done my application for the club. So perhaps something like this with the handle popped out the floor of the tender **LINK**

More concerned about the not sharing the manifold. That sounds like a bigger change to the boiler. Guess we see what has to to be said