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Member postings for BOB BLACKSHAW

Here is a list of all the postings BOB BLACKSHAW has made in our forums. Click on a thread name to jump to the thread.

Thread: Hercules Steam Crane Tubal Cain
27/01/2020 12:31:59

I am making the cylinders out of brass and about to put the steam ports in, I was thinking of putting two condensation taps on the two cylinders.

I have made a boiler and have tried it out on one of my stationary engines but had more hot water coming out of the exhaust as the cylinders were cold so I gave up on that. The boiler works well with a good amount of steam which incorporates a superheater.

I will make a boiler as shown on the steam crane drawings but have others that have made the crane had the problem of wet steam, and would two taps make much difference.


Thread: Morse Taper Removal
25/01/2020 11:50:46

Works on my  SX2p.

Bob dscn0950.jpgSX2pW

Edited By BOB BLACKSHAW on 25/01/2020 11:53:11

Thread: Why is my silver steel undersize
21/01/2020 17:38:06

I float ream when using the tailstock so I know that the hole is correct to size, and the rods are round as they measure the same at two points. I never trust the tailstock or the tailstock chuck as I always find that the hole is oversize, but I'm only using these Chinese made ones, I would like to get a Jacobs chuck but will this improve the hole size? the tailstock is good using a feeler gauge on two points.


Thread: Fly press weights.
21/01/2020 14:28:17

If you need any advice on tooling and how the press can be used for fine limit work. PM me.


Thread: Why is my silver steel undersize
19/01/2020 11:47:39

I have no idea where the printer was made I got it from a charity shop as not working but I have had another printer in the past the same 7.92mm, nether thought about imperial size as everything now is metric.


19/01/2020 10:46:06

Thanks for the replies.

I have checked my four callipers, one is a Mitutoyo and three micrometres with slip gauges so I am confident that they are correct, they all read the same on the silver steel as .025 undersize, I also put two together and .05 undersize. All of my silver steel reads .02 t0 .025 under, I brought the steel from a well known seller on this site, so I shall try another supplier as suggested by Jim. The hole size is correct by making a plug a fraction under 5mm to fit the bush which I done this morning.

I also noted that the 8mm rods from old printers are undersize by .08mm which I've used for axels and made bushes to fit,any reason why?


18/01/2020 18:08:07

I'm using silver steel for a axel, and have reamed 5mm on two pieces of brass bar which are the standards for the steam crane I'm making. Having found a slight play when together I measured the silver steel and its .03mm undersize. I have measured all of my silver steel from 10mm to 3mm and all measure undersize, why is this ? I now have slight play and a bit annoyed as I will have to turn the axel to fit the standards or find the correct 5mm size. My question,is all silver steel undersize.


Thread: Hercules Steam Crane Tubal Cain
16/01/2020 20:08:05



16/01/2020 20:05:38

Thanks Jason and Bill

Its so obvious looking at the photos and the word oscillating, I had it fixed in my head that the cylinders didn't move.

Looking forward to get it sorted tomorrow.


16/01/2020 18:15:25

I am making the steam crane but going by the book of Tubal Cain, I am not using any castings just brass and what's about in the shed.

I cant understand the drawing in the book on the cylinder steam ports that connect to the standards.

The standards have four holes, drilled No 46 but cant understand how this fits to the cylinders,the drawings are sectioned drawn as two holes.

I'm obviously missing something here, any help please, I've made about 1/3 of it so far and hope to finish it.


Thread: Lathe tooling chart
30/12/2019 10:22:33

Hello Chris,

On the internet, mikesworkshop, gives some details and charts.


Thread: Lucky find
28/12/2019 17:33:51

Thanks for the replies,

The photo I've taken does not give the how well they are made,the pivots have two machined slots then screwed together. Early twentieth century could well be correct as the box has a fabric type covering with a silver name plate, so much better quality then todays sets .


28/12/2019 10:33:45

dscn1160.jpgI was given the Haynes book on Stephenson`s Rocket for Christmas and reading through the book I come across a photo of Brunel`s drawing set.

Yesterday I was in Bedford looking around some charity shops, and looking through a large basket of boxed items I found this broken box with all the instruments at the bottom.

I instantly recognized them as the same as Brunel`s instruments in the Rocket book. They are in very good usable condition, actually better than what I could buy that day in Bedford, they are so well made.

As they must be made by the same company as Brunel`s drawing set, and have lasted in the condition of the photo, what type of coating and material did they use? as there is no trace of corrosion what so ever.


Thread: Boiler making problem.
17/12/2019 10:13:24

I've sort of finished the first boiler, just needs the wood cladding on it and some brass bands. I made the boiler 67mm dia with six 8mm tubes crossing the flue with the top having a few rings of copper tube for the superheater, the pressure gauge comes off the safety valve extension tube, it blows at 40ib but needs a stronger spring.. I found the silver soldering quite easy with the correct burner. just needed some practice first and confidence, I was concentrating so much on the job when silver soldering that I put the tube upside down so the water gauge is more at the bottom but seems ok. All the fittings took the time and are cheaper to buy then make. The base is a baking tray nicked out of the kitchen but needs more air vents as the gas tends to go out when more heat is needed. I pressure tested it at around 90lb and held up ok so I'm confident its fine, it has a 18g tube and feels quite a lump. I intend to make a 4 inch boiler next this is 16g and will be a different design, horizontal, Ive got all the tubes needed, just not the silver solder.


Thread: Propane gas adapter
10/12/2019 16:53:31

Thanks for the advice, I have four types of gas canisters and thought at least one would have fitted.


10/12/2019 14:48:15

I have just brought this propane gas burner, but what type of propane tank will this fit. The adapter should fit the hand held tank but has no thread for it to hold on to, the other that is on the gas tube what type of tank do they fit. The propane tank that dscn1148.jpgI have is just a blue tank with the dimple that is used as a pierce fit. I have tried my local DIY shop and non of his gas tanks fit.

Thanks Bob

Thread: Beginners models
10/12/2019 09:56:32

I had a very basic training with lathes and milling many years ago then brought most tooling that's needed over four years. I'm still learning the hard way so bar stock is the way to go for me,l would find castings even after four years a hand trembling experience and mind concentration that I will muck it up, so not yet for me. I started with Elmer's engines which are free on the internet I learnt a lot doing them then done a couple of Potty mill engines. Just the cost of materials needed plus a few bolts and not the worry of mucking up an expensive casting till you feel confident that your ready for that.

Still learning the hard way. Bob.

Thread: Silver solder
06/12/2019 11:57:00

Thanks for the replies which has helpt me a lot here. This is the first time for a large silver soldering area that I've done and so far it has not come out to bad, but if starting again could of done it better.

My next dumb question is pressure testing it, obviously a non return valve. I was thinking of using a cycle valve but this would melt the rubber washer when making a fitting into the 1/4 ME thread bush, not sure what thread the cycle valve is and will mean buying a cycle innertube.

What other ways of doing this please


03/12/2019 15:57:19

I am silver soldering a copper boiler and have used two melting point rods. A part that has been solder using high melting rods I think has not quite taken, is high and low rods compatible if used together. When I use the low melting rods I want to touch up one of the bronze bushes.


Thread: LPG heater- fumes
28/11/2019 12:40:31

As above comments don't use the open flame, look at a green house when using paraffin ln the morning full of condensation on the glass. When buying a electric fan heater check that the thermostat shuts off between a few degrees. usually the cheap fan heaters don't. I use a fan heater which clicks on and off set at a low temperature all night and no problems with condensation.

I have a Carcoon for my MGB but I don't use it, its covered over with a cover and a fan blowing underneath with two carpets on the concrete floor and no condensation.and in my opinion as good as a Carcoon. So air circulation and insulation is all I have found needed over winter.


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