Thread: Whisperings

Originally Posted by Michael G

Nice one Phil. Was the D bit relieved at all? (ground back the non cutting side for example?). Never properly used one, especially for a form, so interested to know how you arrived at your geometry.

Michael

It's a form tool. If you grind away half a cylindrical shape, it's relieved on both sides.

Widely used in gunsmithing to make one-off rifle chambers etc. You can't take much of a cut is the main limitation.

PDW

Originally Posted by PDW

It's a form tool. If you grind away half a cylindrical shape, it's relieved on both sides.

Yes, but Phil said he left it a thou high I think. Although leaving it full form may work (and in brass is probably good to avoid grabbing), I wondered whether a bit of relief to reduce rubbing at the cutting end may make it more effective - or then again may make the tool less stable and cause chatter. Don't know.

Michael

Hi all
first up, many many thanks for the kind words which I find hard to take guys. I am always sitting here in awe of the stuff you guys do. I have learnt heaps just by joining this forum, easily one of the smartest things I have done. Learning this game is an endless journey and I'm in the fun part of the trip where I get to use what little I 'have' learnt to do stuff I like...and get paid!

Hi Michael
It was actually 0.0008" (I love being able to work to those tolerances again) and was left high so I could hone the face down to what I needed but when I grabbed the stone it looked like I had used a circular saw across its face, which reminds me, I must finish the stone dresser I started a while back.
As it came off the surface grinder better than I thought I reckoned giving it a crack was worth it. I am very happy with the results.
No relief is required on a 'D' bit as that is the nature of the beast support wise, plus, and I'm not sure about this, but you have an extra cutting edge if the lathe is run in reverse. In theory that works.

Phil

Hi all
the lubricator drain plug worked, woo hoo!
I have an issue when cutting threads where I take great care in getting the gear train right then blank out when changing the levers on the headstock for the correct TPI. Because of this I always check the thread with thread gauges.
Not possible on this one with any certainty so I had to go back to basics.

Also, because it wasn't practical to disengage the half nuts and I couldn't see all that well inside the bore I have cut from the inside out with the tool facing the backside of the bore.



Phil
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We are fitting an injector to one of the boilers at work to give us an extra means of putting water into the boilers.
To do this I need to make a flange that is not available off the shelf.
It is being made from a piece of 70 mm thick plate which I asked to be cut out round as it was going to be a flange and when I got back to pick it up it was square.
Just means a bit more machining than initially thought.
After marking out I used my wobbler to get the centre running true.
More on this job soon.

Phil
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Hi Phil,
If it was my job, I'd have sent it back as it wasn't what was ordered.
Thanks for the pictorial how to, always wondered how it was done and what was used. Something else to make, it will be handy anyway if and when I get a decent lathe.
Kryn

Thanks for that Phil. How big is the piece of plate (you mentioned 70mm thick but not the width).

Michael

Originally Posted by KBs PensNmore

Hi Phil,
If it was my job, I'd have sent it back as it wasn't what was ordered.
Thanks for the pictorial how to, always wondered how it was done and what was used. Something else to make, it will be handy anyway if and when I get a decent lathe.
Kryn

Hi Kryn
after visiting every steel supplier in town I started to visit heavy engineering places as well. The place I got the piece from is the place that fabricated the beam pump for us. The owner is a major restorer of vintage heavy vehicles and machinery and actually shipped a large Harris engine overseas and went on tour with it. I needed a piece at greater than 2" thick as the final size was a minimum of 2" after cleaning up. A bit more was preferred. I wasn't expecting the bit for 3 days but he managed to get the bit cut before I had finished shopping for some other bits so I can't really complain.

Originally Posted by Michael G

Thanks for that Phil. How big is the piece of plate (you mentioned 70mm thick but not the width).

Michael

Hi Michael
I think in one of the pics you can see a scribed circle, that circle is 6", the size I need to end up with to match the flange on the boiler so it is about 170mm square(I should have checked )
The bore of the flange needs a 3/4" BSPP thread to take a short length of pipe which will have have a tapered thread on it. I tried to buy an appropriate die or pipe threader like a Rothenberger or Ridgid but to no avail. In fact they all laughed at me and said" nobody cuts threads anymore. I have a Ridgid but it starts at 1" and goes to 2".
I visited my dad yesterday and he happened to have a brand new Warragul die plus the stock he used to repipe his sisters house back in the '60s, never been used. I have it on permanent loan.

Phil

Originally Posted by neksmerj

Phil, following on from Combustor, do you have apprentices training along side of you?

Indeed, what would happen if you got crook and couldn't turn up for work?

On a side note, what's happening on the home shed front?

I know, I'm a bit of a sticky beak.

Ken

Hi Ken
no apprentices, they only want to learn G code nowadays, not basic engineering skills. It doesn't look good.
If I get crook, I have to get better, simple.
No new shed on the horizon yet but I do have some doors so it is at least lockable. Maybe some real power instead of an extension lead though could be coming up.

Phil

Originally Posted by Steamwhisperer

Hi Kryn

The bore of the flange needs a 3/4" BSPP thread to take a short length of pipe which will have have a tapered thread on it. I tried to buy an appropriate die or pipe threader like a Rothenberger or Ridgid but to no avail. In fact they all laughed at me and said" nobody cuts threads anymore. I have a Ridgid but it starts at 1" and goes to 2".

I would have fabricated it using a threaded pipe toe welded to the flange. No thread cutting needed. My boat has quite a few of them for seawater intakes.

PDW

Originally Posted by PDW

I would have fabricated it using a threaded pipe toe welded to the flange. No thread cutting needed. My boat has quite a few of them for seawater intakes.

PDW

Hi Pete
I'll need a pressure pipe ticket in our situation but threading I am allowed to do myself, plus, it is a lot easier to replace the sparge if and when it needs it if it's threaded.
Damn welding tickets!

Phil

Hi all
I nearly got the flange for the sparge pipe finished but...
Instead of screwcutting the thread I managed to procure a BSP parallel tap to do the job. The tapping size is 24.5 mm, it even says that size in my old Newnes Engineers Reference Book so that's what I bored the hole out to, ran the tap through, grabbed the fitting which isn't one of the normal cheap fittings we normally are made to buy but 3000 lb rated one and it nearly fell into the hole.
I showed it to the boss and we both agreed it wasn't acceptable to us, although it is to the wider community apparently.
The boss said to get another piece of steel and start again but this time we will use a BSP taper tap.
I rang and asked the guy to cut me another piece from the 70 mm plate they had but this time I really needed it round. I need to finish the diameter at 6" (152.4mm) so we agreed on 160mm.
The guy cut on the wrong side of the line and I ended up with 156 mm diameter with a bit of a blowback in one spot and the edge of the plate in another.
This is a situation that required careful laying out. I put the centre punch to one side away from the blowback scar and scribed the line to make sure it would machine up ok and used my wobbler again for real instead of just a demonstration.
It cleaned up beautifully.

Phil
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Hi.
What would be wrong with reclaiming the first piece by tapping it up to 1" and using a reducing bush?
Jim.

A joint is a potential leak/ failure point so they are avoided wherever possible (we have the same problems at work with hydraulics). A stack of fittings may get you out of trouble as a short term fix but would be considered bad practice as a permanent installation if there was a simpler alternative. I'm not sure about steam but there may even be rules in the appropriate codes that formally disallow doing that sort of thing.

In Phil's case as the public view the machines there may be aesthetic reasons too.

Michael