Here is a list of all the postings Norman Rogers has made in our forums. Click on a thread name to jump to the thread.
|Thread: No wonder my swarf bucket is full|
I manage 100% swarf rates quite regularly but that's more usually known as scrap!!
|Thread: Graham Howard and Brunell Steam Model Engineering|
Graham occasionally makes some vague promissory noises but my experience is of someone who simply fails to deliver.
|Thread: Gear cutting|
It's a thumbs down from me for Brunell ...
|Thread: Bevel gears again|
Andrew: re cutter cost, they weren't cheap, £235.80 for two, includive of VAT and carriage!
Andrew: you may remember you and I had some similar correspondance a while back .... I managed to find a company that could manufacture these special BEVEL cutters and ordered those required for my D&NY TE (12DP). Haven't cut the bevel gears yet but at least in theory I now can. The firm in question is C R Tools in Sheffield (usual disclaimer). Hope this helps
|Thread: The penny has finally dropped|
I have 'adopted' three part finished projects and would never condemn the previous builder; you need to accept that he/she was having a go and that is what really mattered, particularly to them. Yes you can end up doing a complete re-make on some of the work but like Brian says you will often get a bargain that is hard to refuse .... that's how I come to have three on the go right now!
|Thread: Gear cutting|
Up to a point, and according to length, they could be done on a horizontal mill; in the motor industry I believe they are cut using broaches or at least used to be.
|Thread: Bevel gear calculations|
Just picking up on one of Andrew's comments earlier in the thread, C R Tools in Sheffield (usual disclaimer) still list BEVEL gear cutters and so I bought those required for cutting my own differential gears.
|Thread: Live Steam Loco Questions|
Stewart: the help is slowly arriving! Reading is good, joining a local Model Engineering club is much much better and once you start to develop 'a feel' for the hobby then you'll need to make a few choices. Is there perhaps a locomotive you have always liked, or are you not too fussed? Perhaps go for something reasonably straight forward and save your master piece for the second build. In either event take a look through the catalogues of the main suppliers - Blackgates, Polly, Reeves 2000, GLR, GS Model Supplies .... they may have the castings etc for the locomotive you like or there may be one that catches your eye. You'll also get some idea of the costs involved. Simplex is a good all rounder but there are many others. I'd suggest 6 driving wheels and 5" gauge, that way it'll pull a big lad and a few mates at the same time.
As Geoff says it'll take over your life but it's not a bad way to pass the time!
|Thread: Cutting bevel gear wheels|
Thank you for your additional notes. Unfortunately I only have a couple of these bevel gear cutters in the required DP but not #1 or #8 and it seems these are no longer commercially available. I think there's a word for that!
Andrew, sorry I missed your post's arrival whilst scribing .... thanks for the additional information around the bevel cutters, the orginal design clearly involves a different approach to the bevel gears. I'll have to do some work to figure out if I can use the bevel cutters as I have them to hand!
Hi Neil, I did pick up on that from earlier forum posts, the SIN / COS error influences the calcuations of the OD of the large and small end ..... but all of Ivan's methods for forming the bevel teeth rely on the Pitch Dia employed being at the small end not the large. You can't get 60 teeth of 12 DP on a 3.5" dia yet that is effectively how John Haining drew it and then the 2nd and 3rd cuts are happening inside the PD rather than outside with negative correlations. I can't help thinking the original design is flawed. Calcs suggest that 18 DP would work reasonably well (close but imperfect) but before going there I just wondered if I have overlooked something.
I’ve reached the point of cutting the compensating gears for the Durham & N Yorks TE in 2” scale as per John Haining’s design in which the main bevel wheels are described as having a Pitch Line Diameter of 5 inches, overall OD 5.018” with 60 teeth of 12DP. Cutting 60 teeth of 12 DP brings the teeth to a point on the inside diameter (circa 3.5 inches) and then goes horribly wrong in the 2nd and 3rd passes. The design as laid out therefore appears contra to the methodology described by Ivan Law, particularly when trying to form the teeth as Ivan’s approach takes the inside/small diameter as the PD and works outwards. First question therefore is has anyone successfully cut the compensating gears as set out in John Haining’s drawings? If they have then I would dearly love to learn where I am going wrong. On a separate but connected note, I have found in my box of possibly useful things a couple of 12DP cutters that have a tooth width more in keeping with 18DP. They are however marked ‘12DP Bevel’. What might be their origins and could/should they be used rather than the standard 12DP involute cutter, although that still leaves the problem of how to correctly do the 2nd and 3rd passes to finish the tooth form?
|Thread: Bit of fun.|
Looks like something that had the misfortune of going via my workshop!
|Thread: Expansion LInks|
I drilled and filed my first set of expansion links ... they're still in the Maisie 30+ years later but due for replacement. I then used the swinging arm technique to great effect but now have the luxury of a rotary table. I found that light cuts with a new cutter was the key and I'm sure you will be well pleased with the outcome.
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