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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: Aircraft General Discussion
16/06/2018 14:01:41

I flew in helicopters to and from work offshore for 40 Years. I hated them most when I was outbound and only hated them slightly less when I was homeward bound. The one time I was flown off sick, to be honest I couldn't have given a damn if we made it back or not I was in so much pain.

Thread: Motorcycle General Discussion
26/04/2018 09:25:51

Seriously Jim, I contend that anybody who has built a model locomotive or model I.C. engine should be able to make their own cases from solid. It does take skill and more than anything determination and a willingness to accept that if it goes pear shaped you have wasted a lot of money on a large chunk of aluminium.

A bit of research and permission to take a bunch of pictures and measurements at the National Motorcycle Museum was required to provide the basis as well as similar cases from the 350cc Side valve model to copy from. A profile drawing was made and the first process after that was to machine the internal cut out for the flywheels and bearing housings. This was followed by the outside profile and then the contouring of all the various external features, leaving material that couldn't be machined to be finished with the Dremel.

25/04/2018 17:18:58

Hi Ronan,

Triumph cases are very thin in comparison to the BSA parallel twin cases. The beauty of using billet material is that the material is consistent throughout and can be machined with constant thickness and be beefed up where required without affecting the outward appearance too much.

25/04/2018 17:16:03

Hi Jeff,

I made a crankshaft up from an original pair of flywheels and had three sets of spiral bevel gears cut for the bottom end cam drive.

Bob

25/04/2018 17:16:02

Hi Jeff,

I made a crankshaft up from an original pair of flywheels and had three sets of spiral bevel gears cut for the bottom end cam drive.

Bob

25/04/2018 12:04:40

Cause it is Jimmy,

here's one I did earlier. Cut from solid on a round column cheap manual mill and an 8"rotary table. Finished off with a Dremel and lots of elbow grease followed by shot blasting to make it look cast. Everything you see there except the cylinder, cylinder head and cam box are made in the home workshop. It's a 1929 Humber 350 OHC.img_2133.jpg

Thread: The Workshop Progress thread 2018
25/04/2018 10:07:26

I've been meaning to finish two of these off for the last year but I've been busy with lots of other stuff. They are rear hubs for a veteran Triumph motorcycle circa 1911. The body was machined on the Tormach mill using the Rapid Turn Lathe attachment. It struggled with the 2 1/2" diameter material (EN8), but I got there in the end. The profiling was done entirely with a 2mm wide grooving tool. Turning without chatter initially was a problem but as the diameter reduced it became easier.

The ratchet on one end is from a damaged free wheel chain pinion that was used as thread gauge.

img_2998.jpgimg_2997.jpg

Thread: Latest Update of Fusion 360 seems to have omitted the Tormach Slant pro from it's list of Post Processors
19/04/2018 13:50:15

Today I modified a programme for my Rapid Turn lathe attachment and went to produce the G-code from it but noticed that there had been an overnight upgrade. When I went to post process all I could find was Path Pilot, which previously was for the PCNC Miill and there was a processor for the Tormach 150 Slant lathe which was also the one to use for the Rapid Turn.

If I use the Path Pilot option it just keeps coming up as Download failed.

Has anybody else had similar problems ?

Thread: What did you do Today 2018
05/04/2018 16:06:45

Tracy Tool have always provided a good service. I have ben using them since 1980 and can't remember any occasion where the stuff ordered didn't turn up in the next post.

What did I do today, I cleaned and polished my 1959 BSA A-10. I went for a run on it last week and it was filthy with salt mud and general crud from damp roads, I had sprayed it with ACF-50 before I set off so I wasn't worried about the salt causing corrosion. All the muck washed off easily but the one job I hate is cleaning and polishing the Alloy rims and the brake plates, you are almost guaranteed to stub your fingers against a spoke or catch the ends of the split pins in the brake clevis pins.

Thread: Milling ali
03/04/2018 11:15:56

Richard,

I assume the block is to be machined completely through. If it is I would advise drilling through holes to take out most of the material. The drilled holes will also act as drain holes for coolant and allow cuttings to clear, which is essential for aluminium to avoid cuttings building up on the cutter which will result in the cutter snapping. Take cuts of about 1/8"- 3/16" max with as high a speed as you have. Listen out for any signs of chatter in the form of a high pitched screaming noise and reduce the feed/RPM to get the optimum rates.

Good luck.

Edited By Bob Rodgerson on 03/04/2018 11:16:44

Thread: In-line Diesel Engine Model
21/03/2018 22:40:28

You are on the right track Fred. It would only be possible to do this with a vertical or possibly Vee formation engine.

21/03/2018 15:41:24

I made a 22 cc compression ignition four stroke engine with variable compression ratio controlled by moving the crankshaft up and down. For fuelI used a mix of paraffin with 10% lube oil and about 1-2% easy start. It was successful and flew a model aircraft quite well. It has a lovely sound especially when opening the throttle with a very distinct Diesel Knock. I displayed it in a model at Elvington about 1999, quite a number of people who thought they knew it all told me that my engine needed looking at because you could hear the big end knocking.

it f I'm not saying how I moved the crank shaft up and down but will leave you guessing.

Thread: Problem With Corrosion Of Stainless Steel
10/03/2018 23:51:04

Hi all,

thanks for responding. I have heat treated 10 buttons tonight and will see if this improves their corrosion resistance.,

The same material has been used in the past for this application but nobody can tell us what surface treatment was used ,if any.

I should point out that I am not dealing directly with the power station but with a sub contractor who specified the material. I m trying my best to resolve the problem for him because it has cost him so much money with people being pulled off the job twice while the problem was investigated.

10/03/2018 16:43:05

Thanks for the responses so far,

T.M. one sample I have out in the open air is one that I polished and dunked in citric acid in the form of lime juice for a few hours and so far it seems to be OK. The problem I would have would be polishing 1500 of them quickly thus keeping costs down.

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.

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