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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: Problem With Corrosion Of Stainless Steel
10/03/2018 15:14:55

I will try hardening and tempering a few tonight in the furnace. There seems to be a fair bit of difference in recommendations, some say passivate some Harden and Temper and others Electroplating (Not actual deposition of metal such as nickel but altering the surface of the metal by passing current through an electrolyte to alter the surface finish).

10/03/2018 15:14:54

I will try hardening and tempering a few tonight in the furnace. There seems to be a fair bit of difference in recommendations, some say passivate some Harden and Temper and others Electroplating (Not actual deposition of metal such as nickel but altering the surface of the metal by passing current through an electrolyte to alter the surface finish).

10/03/2018 13:45:27

Three months back I was asked if I could make 1500 or so Magnetic Stainless Steel buttons from 416 Stainless that were to be attached to various electric motors in a Nuclear power station to enable a magnetic sensor to be attached and removed as required for monitoring purposes.

The job was very simple, consisting of a 23mm diameter X approx 6 mm thick disc with a rough finish on one side and a smooth finish on the other.

First problem encountered after making them was that the powers to be were not happy with the parting pip that had been left, even though they had been dressed off there was still a little raised pip in the centre. They were bought back to me and I re faced all of them with a facing tool and eliminated the problem.

The next problem was very serious and that was that the buttons were rusting, some of them alarmingly so. Fortunately I had the mill certificate for the material so at least I couldn't be accused of substituting stainless with plain mild steel.

Some of the ones fitted showed a complete cover of rust and also some were starting to show signs of rusting in the bag that they were stored in, however one batch of 500 that were completed a few days after the initial batch showed no signs of rust forming. I think though can't be certain that I washed one batch, possibly the first to remove any grease from them because they were to be glued to the motor and I wanted to give it the best chance, I washed them in a strong detergent (Fairy Liquid) and dried them in the oven, it was at the end of this process that I noticed some very small signs of pitting here and there amongst them so I wiped them all clean and sent them off

I thad the ones that were showing signs of rust sent back to me and I took another skim off them.

Yesterday I experimented with various buttons, I soaked two in a mix of table salt and washing up liquid, another couple I soaked for an hour or two in lime juice in an attempt to passivate them, another couple had been laying around the workshop for a couple of months, having been found when sweeping up and another batch I took straight from the machine and placed all of them outside open to the elements.

The results are not promising, the batch that were soaked in washing up liquid and salt had pretty much rusted right over the face, The ones that came straight off the machine were showing signs of slight rust after a few hours, The ones that had been machined a while back were a little less corroded than the freshly machined ones and the ones that I soaked in lime juice were better than the rest other than a slight bit of light rust starting to show on one of them.

The problem looks to be corrosion of free iron after the machining process that has not been removed properly. Would prosper passivating or electroplating improve the corrosion resistance and which would be best?

Thread: What did you do Today 2018
03/03/2018 11:33:01

British Gas installed loads of boilers around 2007-2010 with the stupid design of condensate drain that was placed directly through the wall to dump its contents into the waste water pipe from the Kitchen via a Tee Piece. I always thought this was stupid because it was obvious to me that the very low flow rate from the condensate line would allow the contents of the pipe to freeze building up layers of ice until the pipe became blocked. This is exactly what ours did in the severe winter frosts of 2010 (- 18Celsius recorded at Woodford Cheshire just a mile down the road from my place).

At the time I did't know what the problem was and called out an engineer who told me what the problem was and that hundreds of people in our area were suffering the same problem.

I contacted B.G. regarding this and, despite it being in my opinion, a system not fit for purpose they wanted £200 to re route the pipe inside the house to join the drain at one of the available spare entry points on the connector under the kitchen sink.

They no longer fit them with external drains as a result of so many calls during the winter of 2010, which as far as I am concerned is evidence of the system not being fit for purpose but I am Bu**ered if I am going to pay them to put it right. When I can be bothered I will re-route the pipe into the internal side of the drain system for the kitchen.

Edited By Bob Rodgerson on 03/03/2018 11:34:48

Edited By Bob Rodgerson on 03/03/2018 11:35:24

Thread: Large Lathe - 16 feet diameter faceplate.
02/03/2018 16:12:20

I can remember seeing lathes with impressively large face plates when I worked for The Wallsend Slipway And Engineering Company in the early 60's. There was one particularly large on that had open gearing with wire mesh guards around it that was used to machine the steam turbine blade tips that were fitted to RMS Mauritania in the early 1900's. These turbines were single reduction geared and the rotors were 15 ft in diameter Here is a link to a picture of them https://goo.gl/images/WpnVr1.

At the time I was there the lathe was still in use and was used for machining mixing paddles that were of a spiral type that obviously ran inside a cylindrical drum.

Thread: new toy and my latest engine
27/02/2018 22:17:46

Hi Geoff,

Looks like the previous owner was doing a lot of valve seat work judging from the seat cutters in the tool box.

Thread: Spotting Drill or Centre drill.
27/02/2018 15:37:36

I use Spotting drills on my CNC Mill a lot they are very good for spotting holes and also for machining small chamfers on work.

Thread: Motorcycle General Discussion
15/02/2018 09:58:30

Hi Ronan,

Vertically split crank cases were a natural and easy way to make single cylinder engines. When the parallel twin without centre bearing came about it still remained the way to go, there were a few odd exceptions such as the AJS and Matchless twins which had a centre bearing fitted in a split housing that could be inserted and bolted up when the crankshaft was inserted into the cases.

However once multi Cylinder engines became the norm, there was little choice but to split the cases horizontally, car engines have been made this way for years or with underhung crankshafts and a sump cover to hold the oil.

The adoption of multi cylinder engines for motorcycles really took off in the early seventies at a time when most of the British twins and singles were reaching the end of their design and possibly their general working lives. As a result there were huge quantities of tatty, ill maintained bikes on the road a lot of which will have been, in the past, attacked with screw drivers and chisels to open the cases during major maintenance and I believe it is this that gives the vertically split case it's bad name.

If the faces of the joint are perfectly flat and unmarked they will seal, my BSA A-10 doesn't leak despite it being over 50 years old.

14/02/2018 10:22:40

I agree with Mike,

I have on the bench at the moment, a BSA Fury Engine which came out of the research department at Umberslade Hall I am building the engine up from part machined castings and a crankshaft/conrod assembly to, hopefully a working engine when it is finished. It is a long term project that is nearing completion with both crank case halves machined and the lower valve drive train and oil pump drives sorted. The cylinder head will be the next thing to be machined to accept the camshafts and once this is done I will machine the Hemispherical shape for each cylinder before it goes off to a cylinder head specialist to have seats and guides fitted.

The engine is very Honda like being a DOHC twin with the camshafts running directly in the Alloy Cylinder head rather than bearing bushes or needle rollers. Had more money had been available to develop it and improve reliability it could well have become the machine to beat it's Japanese rivals. However I do think that by the early 70's a 350cc engine was the wrong size to go for, people, then were wanting bigger OHC engined bikes and a 750 version would probably have been the right size to go for.

Thread: Looking to develop new skills for hobby and work
04/02/2018 19:19:22

Welcome to the forum Ross. I spent 40 odd years working onshore as well as offshore in the Oil Industry,. I take it that you are re-training because of the downturn. My son worked in the industry too but was made redundant after the company he worked for was taken over by Schlumberger. This was also at the start of the downturn and his prospects were pretty poor so I shelled out and lent him the money to train as a commercial Airline Pilot. He is almost there, having gained his CPL and has been taken on by BMI. He starts his Type rating course next week and at the end of it, in five weeks time and providing he passes the exam, should be flying for them full time.

I don't blame anybody within the industry for getting out, I too suffered during the 10 Dollar Barrel price in 2000, being out of work for 14 months. All that happens, when things pick up again, is the pay goes through the roof because every time a lot of skilled people leave the industry never to return.

I hope you are successful in your new chosen feed and get to enjoy our great hobby at the same time.

Thread: Mystery Screws
28/01/2018 14:59:53

Bill,

they look as though they are designed to hold a ball away from a side outlet on a right angled check valve.

Thread: Lever Operated Collet Closer for the Tormach Rapid Turn
14/01/2018 10:58:33

Thanks Chris, it seems to work well so far. The only really accurate parts to make/modify are the adapter, which is the bright Alloy piece in the picture and the draw tube thread for the collets, other than that it is a relatively simple job to make suitable for the Rapid Turn.

14/01/2018 09:45:41

I have a Tormach PCNC 1100 series Mill for which, when it came out I bought the Rapid Turn lathe accessory that fits to the bed of the mill to become a poor mans CNC lathe.

In order to increase it's usability I made some gang tooling which has so far proven to be worth the effort.

Recently I had an order for 1,575 sensor buttons that were a simple turning job requiring a 3mm slice taken off a 25mm diameter bar with a rough scroll like finish on one face and a parting off finish on the other with chamfers on both edges. The collet closing system that comes with the attachment is draw tube that is tightened and slackened using a 2" long Tommy Bar that fits into holes on the closer tube end. With a cycle time of less than 1 minute it became positively painful tightening and loosening the collet that many times, especially given that the cycle time was less than a minute so I decided to do something about it.

Tormach market a Lever Operated Collet Chuck for their Slant Pro Lathe and I thought I might be able to adapt this for use on the Rapid Turn.

I ordered a unit and it arrived a few days ago so I decided to have a go at getting it to fit. First thing to do was to turn down the draw tube O.D. to suit the Rapid Turn Spindle, next I machined a register on the drive pulley of the Rapid Turn by clamping it to my manual lathe, plugging it in to the power socket on the mill and use the manual lathe cross slide/toolpost with a trepanning tool in it to cut a register in the pulley. With this done I then machined an adaptor to fit the register on the drive pulley and the Index/adaptor of the Lever Operated Closer. The adaptor was drilled to suit the fitting holes in the lever Operated Closer adaptor and the hole centres transferred to the Rapid Turn drive pulley which were then drilled and tapped M^ to suit the mounting cap screws. I then cut the draw tube to length and machined a new thread in the end of it to suit the collets.

Here are the results

dsc_4363.jpg

dsc_4364.jpg

dsc_4365.jpg

dsc_4366.jpg

 

Edited By Bob Rodgerson on 14/01/2018 09:48:07

Edited By Bob Rodgerson on 14/01/2018 09:48:52

Thread: Thread Milling
03/01/2018 10:24:14

Steve, that is what I find so good about using the threading wizard in either Fusion 360 or on the conversational programming on the Tormach mill. Adjustments are easily made but in general if I am using a standard recognised screw thread from a wizard it fits perfectly straight off.

02/01/2018 19:30:27

I have milled plenty of threads on my CNC mill but I use the single thread type thread mills. They cost around £50 but work very well.

Thread: Hemingway Westbury Hacksaw
30/12/2017 09:20:46

I hope that Photobucket charging for their services backfires. I have been inundated with messages from them asking me to take up their generous rates since they made this move which suggests to me they are getting desperate for the business.

They obviously made money before charging for their service but have become greedy.

Thread: HMS Queen Elizabeth: Leak found on new aircraft carrier
19/12/2017 10:45:50

I remember a similar experience from my shipbuilding/marine engineering days 19 the early 1970's during sea trials of the ferry St George. She was experiencing severe vibration, especially when in reverse. It was so bad at the aft end of the ship that in some cabins you couldn't stand comfortably, let alone sleep. I seem to recall that we had a job keeping up with water ingress into the shaft tunnel and the bilge pump was running constantly to keep up with it. It was believed that the welds on one of the hull plates had cracked due to the vibration.

The ship was dry docked immediately on return from her trial and a 25 gallon paint tin was found to be caught either around the shaft or between the variable pitch blade and the prop boss. The plate was welded up and on removal the severe vibration was no longer present.

Thread: Brazing Brass
05/12/2017 07:59:45

Hi James,

It may be that the flux is deteriorating due to being held at too high a temperature for too long, though I haven't had experience with this type of flux.

If mixing flux with water use a little washing up liquid in the water, this helps the flux to spread over the metal so that no areas dry up and become bare before heating.

Thread: Runout turning between centres
23/11/2017 12:04:14

I have found that it tends to be the tailstock alignment that causes most grief. If I am turning between centres and the job requires accuracy I set up and run a test on a bar of similar length, adjust the tailstock as required and then without unclamping the tailstock place the workpiece between centres and finish it in one setting.

Thread: First project
22/11/2017 13:59:23

At a guess a 72" wingspan it is likely to be around 1/4 full size. So the spring Oleos will probably be around 3/4" dia

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