Member postings for PaulR

No fear of that... I'm still trying to think of a use for a 10mm (carbon) die that snapped in two the other day but that one has got me beat so far (except maybe as packing).

Thanks Jason, will give this a blast later!

Um, should have been clearer, I meant how high was the cutting flute set... at centre height as usual? Not having a tool to hand I can't visualise the fall off/relief to think if it would cut properly set like that or whether it would need to be set lower and rotated a little.

EDIT But on reflection it's obviously no different to normal milling just in a different orientation and with the material curving in toward the cutting edge. I must try this later!

Edited By PaulR on 14/02/2017 14:19:37

Very interesting!

How did you set the tool height?

Paul

That would be nice but I don't have the equipment to make a mating part - can't see me milling that in the vertical slide

Thanks Nick. I've got a couple of ground down taps that are very useful. I won't be grinding this die down however - it's now a properly split die! I made the first plug which seats beautifully but as I started the second there was a sharp snapping sound and the die was no more (it died ). First time I've ever done that... that's the price of carbon steel I suppose. So now I need 1x coarse to finish the job and 1x fine (+ tap) for next time. Grrrrr!

Seems to be little difference between the two sides on the dies in this set - the last ones I bought about 10 years back only had a small lead-in on the back.

Yeah it's a standard die... spent a shed load on tooling in the last few month so the finer stuff will have to wait - but point taken thank you. Also need to make up a suitable tool for boring such 'small' holes!

It's for the end of a pump valve chamber so I'd like to keep as much thread as possible on the plug - the part it screws into is already made and threaded. In light of Jim Nic's comments I think I'll make some studding, thread it through a bit of hex and silver solder it together.

Thanks all.

Thanks David - not a bad idea but a 1/8" washer is probably a bit too thick as it would be almost the same thickness as the head!

I have a 1/4" long plug that needs a 10mm thread right up to the shoulder but my die will only allow me to cut about 1/8" before it butts up against the head. I've tried the usual dodge of reversing the die but that doesn't work either.

I don't want to undercut the plug or counterbore out the first 1/8th of the thread so the only thing I can think of is fabricating a plug by making some 10mm studding and threading it through some hex or grinding away the back surface of the die - which might be more useful in future (except that would mean packing it up in the die holder thereafter). My question is, how tricky is this likely to be given that I'll just be using a small bench grinder?

(and why don't they make dies that will cut right to the end anyway?!)

Cheers

Paul

There's a Wolverhampton club (track at Baggeridge Country Park I think) and a Black Country club - I think they meet at Oldbury but not sure if they are loco types :D

I'd come to a send off as I only live a few miles away :D

EDIT: I think there's still a Sutton Coldfield club too but you probably know all this already,

Edited By PaulR on 08/02/2017 15:13:51

Having finished my first very basic hand pump (in my album here http://www.model-engineer.co.uk/albums/member_album.asp?a=42953) I'm planning a hand-powered boiler feed pump like the Stuart or the PMR ones made from castings, before getting on to a 'proper' engine powered pump.

I've seen a plan for those having the right-angle type inlet that screws into the valve chamber body but they seem unnecessarily complicated and fiddly. Having spent 24 hours thinking about this (including a couple in the middle of the night!) I think I've come up with a plan based on this layout:

I haven't seen inside one of the aforementioned pumps but I guess they must be similar. Anyway, the salient points are:

The bottom, threaded, inlet 'plug' is a reel type arrangement with the middle section thinner than the bore of the chamber. It will have a cross-drilled hole and a central hole to admit water.

The top plug has a similar thinner part below the threaded bit. It limits ball travel but allows water around the thinned bit.

The middle bit has a central hole, a cross drilled hole from the ram cylinder and a diametrical slot in the bottom half (these last two bits aren't shown in my crappy model as I don't know how to form them in the modelling software :P ).

The thing that makes this 'easier' is that the centre section can be turned/drilled/slotted and then shoved up the tube, held and silver-soldered in place (via the hole from the ram side and top and bottom if necessary). It obviates the need for creating a truly flat-bottomed hole for the valve seat and drilling the small off-centre holes to allow water to flow past the lower ball when in the up/suction position.

Note: there should be holes in the chamber where the supply, delivery and ram tubes enter (I don't know how to do this in the software I'm using) but you get the idea.

Might be useful for someone - I've just started making one for myself...

As an aside, and I realise this is straying from the original topic, why is a volcano shape conical seat better than a funnel shape which naturally channels the ball to the right place?

Ah, I see - thanks Bob. And thanks Reg for that handy rule of thumb :D

Most plans and posts I've looked at typically give 1/32" lift for pumps with ball bearing type valves. Why so little when it's easy to arrange things so the ball is constrained and can be made to naturally fall onto a conical seat? It seems counter-intuitive for a free flow...

I'll have to untwist it first I only have a little bit of that stuff left and can't afford to waste it on experiments.

With no care at all just tried it on a bit of (annealed) steel - so easy to twist I was surprised. But the twist is uneven: after three complete turns the bottom was more tightly turned than the top. What's the fix, reverse the rod at each turn??

Crikey! I must try this... maybe on some cheapo well-annealed steel rather than costly brass though :D

Nice one Lathejack! How hot did you get it?