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Member postings for Bob Rodgerson

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

Thread: Measurements from the past
05/01/2019 12:07:03

It is common in the oil industry to measure pipe lengths with a steel line tape that measures in decimal feet. Imagine the confusion that is caused when somebody accidentally supplies a steel line tape that reads in feet and inches.

The Oil industry is full of non standard measurements, for instance some companies measure depth in metres but record things such as weights in Pounds instead of KG, volumes in Barrels or cubic feet instead of Litres or cubic metres.

I believe the measure of metric feet was introduced to make it easier to calculate the depth of hole drilled. Depth is measured by tallying the length of every joint of drill pipe or collars run into the hole. Drill pipe is usually around 31 feet in length per joint but varies give or take about 1 ft depending on the number of times the drill pipe thread has been re-cut and the random length of the base pipe which is made within a certain length tolerance, probably around +/- 6". Measure , given that holes of 20,000 ft depth are not uncommon then it obvious why accurate measurement of the lengths of pipes is important.

Thread: Planned Obsolescence
05/01/2019 11:35:16

I use my Mac Book Air mainly for photo and video work plus Cad Cam and Fusion 360 and am receiving the same message as Dr Dave.

As I understand it Auto Desk need to use a higher version of the MAC OS than my Mac book is capable of upgrading to because of limitations with memory etc.

I have had three Microsoft Windows OS. laptops in the time that I have owned this mac (Purchased in mid 2011) and it is still going strong, having been used on a daily basis since then. The Microsoft OS laptops are in comparison hardly used, being kept only to run other software that will run only with Windows. I have become fairly dependent on Fusion 360 so today I bit the bullet and have purchased a new Mac Book that will support the latest OS.Admitedly the Apple is expensive but have proved to be very reliable and I feel I have had my moneys worth from my old one so in a way don't begrudge having to upgrade.

Thread: Christmas disaster
25/12/2018 23:24:15

The day before Christmas Eve the central heating and hot water boiler stopped working just before the family were due to arrive for Christmas. I am covered by a homecare contract but it was late in the day and I couldn't find anybody to speak to, however, on line I was offered a repair date of the 27th Dec.

Unfortunately I misread the appointment message and had somehow assumed that it was for the morning of the 24th. I didn't realise this until the next morning when I checked my phone messages. Clearly this was not good enough so I decided to call the British Gas emergency help line to see if I could get an emergency repair appointment. I was told that before any assistance could be offered I would have to check at the meter to see what type it was and to switch off the supply. I was also told that before any work could be done somebody from Cadent (British Gas Utilities Contractor) would have to come and check that we were getting gas to the meter. I must admit I couldn't see the point, after all why wouldn't there be gas at the meter.

The situation was a bit like breaking down in a car knowing it is beyond roadside repair but still having to wait for an RAC man to tell you that it can't be repaired at the road and having to wait even longer for the recovery vehicle to arrive.

Still not happy I tried yet another number and finally managed to get to speak to somebody and was given a repair date of the 25th Dec which was acceptable.

Meantime a person from Cadent turned up and checked the meter. I was absolutely gobsmacked when he attached a manometer to a tapping point on the meter and got no reading. He thought that perhaps the little valve was blocked so he poked through with a piece of wire which made no difference. Next he disconnected the supply pipe from the meter, sure enough, not even a whiff of gas. His verdict was that he thought that there could be water in the line and he would call out a crew who would get the water out. Within an hour there were a couple of vans on site with a vacuum pump unit. This was coupled up to the supply to the meter and switched on. I was amazed at how much water was sucked out of the gas main. I reckon there was at least 40 gallons of water in there because it took two men to drag the unit onto the driveway and four to get it off. You could see the water , which was clear, through the transparent tube on the vacuum unit and it ran clear for a long time before you could see the odd bubbles in the line.

Anyway once the line was cleared gas supply resumed and the meter was re-connected and checked out before switching on the central heating.

I was really pleased that the problem hadn't been due to my central heating boiler failing and I was impressed with the speed at which Cadent carried out the work to get us back up and running again. It could have been a bit of a problem with all of the family at home for Christmas. I cancelled the Christmas day and 27th Dec appointments.

The thing that gets me is where the heck did all that water come from.

Thread: Vega Twin Completed
08/12/2018 11:29:03

Nice work Cor,

I have made a few engines over the years and promise myself to make some more in the future once I get my two motorcycle projects and my Don Young Doncaster out of the way. I liked the Vega design but I thought it a little small for my liking, there is a nice 15CC Vee Twin design that I believe came from Les Chenery that looks really nice and runs well too.

I don't want to dampen your spirits because I know how good it feels to get an engine to run for the first time but I learnt the hard way not to run an aero engine while standing anywhere but directly behind it. The first time was a really bad one and nearly cost me my thumb when I started my 200CC flat twin and had forgotten to tether the test stand. Trying to stop a 36" prop with your hand, even at tick over speeds is painful to say the least.

The last time was Several years later when I was starting my 27 CC 4 stroke C.I Engine and trying to adjust the carburettor from a similar position as yourself which resulted in a visit to A & E for a few stitches.

It hasn't put me off but i will only be operating them from behind in future.

Thread: Motorcycle General Discussion
30/11/2018 23:06:27

Hi Windy,

within reason I don't think there is much that cannot be made with simple machinery in the home workshop. It takes time and as you will know you have to plan the sequence of operations otherwise you can engineer yourself into a corner you can't get out of.

I have got CNC capability now which is fantastic for generating complex shapes. I have just started a restoration of two Humber 350cc Motorcycles, an OHV and an OHC. Hopefully I will get one finished next year.

30/11/2018 17:07:31

I made the crank cases, inner and outer ignition timing chain cover for this 350cc OHC engine from solid on a small round column Axminster mill a few years back.


Edited By Bob Rodgerson on 30/11/2018 17:07:59

Edited By Bob Rodgerson on 30/11/2018 17:08:59

Thread: Piston ring articles in ME: 4350 vs 4450
14/11/2018 06:55:45

I have made rings using the former method t, turning to size breaking, pegging then heat treating for a Doncaster and also for several IC engines. It is an easy method.

Thread: new toy tormach 1100
15/10/2018 09:22:35

Hi Geoff,

I've had my Tormach for about four years and have found it to be great. I have also got the Rapid Turn attachment and 4th Axis with it. Initially I found the Rapid Turn a bit of a faff and inadequate as far as tool holding went but I have fitted gang tooling to it and it has made it very useful for making small batches of turned components. I have posted quite a few videos on Youtube and am in process of making another video about the Rapid Turn with gang tooling within the next week or so. Look up my channel.

If I can be of any help let me know.

P.S I hope it came with plenty of equipment.


Edited By Bob Rodgerson on 15/10/2018 09:23:06

Thread: Wyvern Piston Ring Suppliers - Advice Please
10/10/2018 17:29:45

Why not make your own. It's relatively easy.

Thread: MEW renewal problems
19/09/2018 09:09:06

Despite numerous efforts the payment website refuses to let me pay for my subscription,always at the last hurdle I press the proceed to payment option and it keeps returning me to the same page but gives no reason as to why.

I have looked everywhere on that page to see if I have failed to tick any boxes such as a terms and conditions box but can't see any.

Is this just a problem for Apple users (for instance when you hit the enter button with an Apple macbook the cursor returns to the top left of the page. This is damned annoying but has been this way for years). Or is there a problem with the My Time site?

Edited By Bob Rodgerson on 19/09/2018 09:09:32

Thread: New old 1950's Myford 7 Lathe still in the crate
10/09/2018 16:44:32

The Myford super 7B currently in the classifieds at £1,234:00 makes the one in the crate look like a dog.

Thread: Mass Production
05/09/2018 08:53:41

BobHi Jon,

no problem tapping but I've only done one prototype. I have a batch of 70 or so to make which I will do on the Tormach with the Rapid Turn set up and this will be a test to see how well it goes. I think, because the holes are shallow it makes it easier. The bore size of the other end is not critical so I will drill this with a flat nosed carbide drill.

Beyond the first batch I think that thousands of these things will be required, hence the questions about which is the best way to mass produce them.

03/09/2018 22:06:12

Thanks for all the replies, it looks like a repetition lathe or Cam auto could be the way to go.

03/09/2018 21:53:51

Posted by Neil Wyatt on 03/09/2018 10:27:02:

If the M6 hole can be made right through so all the machining is done from one end, it would be a one-setting job.


M^ hole must be blind so no easy fix.

03/09/2018 21:52:57
Posted by Andrew Johnston on 03/09/2018 09:09:07:

Bob: Not enough information! What material? What tolerances are needed? If the component is 26mm long with a 17mm recess one end that only leaves 9mm for the M6 thread. If you really want 8.5mm of thread that only leaves a 0.5mm wall thickness. no tap is going to do that. You'll either need to screwcut or thread mill.

In theory any capstan or repetition lathe could do the job, athough the M6 thread is tricky. But I think all would need a second op. And I'm not offering to make them!

Personally I'd change the design to make it easier to manufacture.


Hi Andrew, Material is 316 Stainless, tapped hole is tapping drilled 9.5mm deep and tapped as deep as possible, not sure what you mean by 1mm wall thickness because at this end of the work piece it is 18mm dia. The other end is 18mm O.D X 15mm bore X 16mm or so deep.

I have made the prototype on my manual later and am sure I could do it on my Tormach with the Rapid Turn set up using gang tooling and the lever operated chuck, however I have no desire to stand at the machine manually loading it and then turning the part around to carry out the work on the opposite end.

03/09/2018 08:41:54

I am trying to find out what type of machine would be used to manufacture several thousand simple components from round bar of say 18mm dia with a 15mm Dia X 17mm deep blind bore in one end and an M6 internal blind thread *.5mm deep on the other end, the whole job being no more than 26mm long.

Pre-CNC days, how would this have been done? What modern CNC type machine would be used today?

Obviously the job could be done by programming a simple single spindle CNC machine to carry out the operations on one end of the bar then part off but the components would have to be re-loaded the right way round to carry out the operation of drilling and tapping the hole in the other end. This would be extremely time consuming and would probably take longer than the drilling and tapping operation itself.

Thread: Aluminium eccentric
25/08/2018 09:36:06

"The probem is that small particles of aluminium wear off and oxidise. Aluminium oxide is used to make grinding wheels.


If this is the case, how come most IC engines are running with Aluminium pistons.

I see no problem with using Aluminium alloy for eccentrics, provided eccentric straps are made from case hardened steel. However, the environment beneath a Locomotive boiler is hardly conducive to longevity of nearing surfaces.

Thread: Vertical Boiler Fittings
15/08/2018 21:46:12

I use Wellseal on my Motorcycle all the time. It's really good stuff for getting a good seal on mating surfaces. It doesn't harden and can be cleaned off with methylated spirits.

Thread: Valve guides
04/07/2018 07:47:01

I made and fitted a couple of new guides to my Humber 1929 motorcycle yesterday, the old guides were OK but I have fitted modern valves which are a lot more durable than the original which are prone to drop a head.

Cast iron was the material used originally and is best used in exposed valve gear as it wears less readily when exposed to road grime compared with phosphor bronze.

Thread: Flashing red LED lights
17/06/2018 15:32:09

Halford sell them as bike lights but might be pricey compared to direct from China.

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