Here is a list of all the postings Paul Janes has made in our forums. Click on a thread name to jump to the thread.
|Thread: Oxy Acetylene or Oxy Propane?|
I use Oxy/Propane with standard nozzles and also a big heating torch but it requires a different regulator. For welding steel, I use Mig, Tig or stick.
Edited By Paul Janes on 01/10/2018 20:38:22
|Thread: Warning, Modern Methods in Use|
Mick, My comments about CAD where in response to the original question about "what use is it in the home workshop".
CAD is just another tool that can be used in manufacture. It is not necessary to make anything, just assists to make it easier. Similarly, we do not have to have a digital readout on a milling machine. Just makes machining easier. We can produce models just as good by using the standard vernier scales.
I have been producing drawings all of my working life. Firstly on a drawing board, then on computer and use CAD because I have it available. There are good, free packages on the internet and it is worth the effort to learn to use one. Saves a lot of mistakes in the workshop.
The scaled accuracy of drawings made by hand is only as good as you can draw a line and 0.2mm is about as accurate as I can measure by eye. Measuring the overall length of something with a rule is only as accurate as the drawing. Therefore to get an accurate overall length of multiple parts you have to use a calculator to add up all of the length of all parts. (this is how we did it in the old days on a drawing board before computers. And used slide rules before calculators).
With CAD you can draw something which had hundreds of parts and measure the overall length to 0.00000001.
Many of the old drawings of machines which we model are drawn in inches. CAD can draw these using inches and display duel dimensions in mm without the use of a calculator to convert the inch measurements
CAD is only a tool that makes it easier to draw.
I am an amateur machinist and consider the use of a CAD software a great tool for making models.
The old, imperial (inch) drawings which I received for a traction engine have to be re-drawn to suit metric steel sizes. This could be done by hand drawing (~0.2mm accuracy) and calculating the dimensions with a calculator
or use CAD (0.00000001 mm accuracy). More accurate.
3D CAD models allows me to completely build my model on the computer before I make it in the workshop which is much quicker than re-making mistakes on a lathe and mill and far cheaper,
|Thread: dim tolerances|
We only get what we pay for. The set of drawings for my traction engine cost less then $100. If they were to a professional standard they would cost $ thousands. Too expensive for a model maker (or me) to buy. They do however contain most of the data needed to create a working set of drawings. I am fortunate that I work in engineering as a design draftsman using Solidworks to model all of the parts and then create fully detailed workshop drawings. For those not so skilled I would suggest that they join a model club who have members with an engineering background. Most will be happy to advise and help.
(Note. My previous post about allowable tolerances was a practice for the length and width of components. Shafts, bearings, etc are dimensioned with suitable limits and fits)
It does not take much more effort to add tolerances. A simple method which was used in the past was to dimension with a different number of decimal places to specify the importance of the dimension.
The allowable tolerance is half of the last digit. eg.
50............. 49.5 - 50.5
50.0......... 49.95 - 50.05.
50.00....... 49.995 - 50.005
Edited By Paul Janes on 28/02/2014 09:04:51
Edited By Paul Janes on 28/02/2014 09:05:25
Edited By JasonB on 01/03/2014 09:52:46
|Thread: 4" Foster beginner's build|
I am building a 6" Ruston Proctor SD. Probably about the same size as your 4" Foster. Not being a machinist, I was advised by one to start at the front wheels and axle. Not too hard to accomplish, you learn a lot of skills and soon have something to to be proud of. Don't just just go to LSM for laser cut parts. Shop around and you may get a better price. I live in Australia and quotes for plates for my boiler and horn plates ranged from $600 to over $1000. Not everything has to be laser cut. (normally costs more than oxy cutting). Laser cut tolerance can be within 0.3mm but oxy profile cutting within 1-2mm.( Some of my photos are on Traction Talk in the model section).
P.S. Double check all of the dimensions on the drawings. A lot of mine are wrong.
Good luck, Paul
|Thread: dim tolerances|
Many of the model drawings are not prepared by qualified draftsmen or engineers and often do not contain tolerances. My biggest complaint with model drawings is that they are not always correct. Often mating parts do not match or are dimensioned incorrectly. Double check all dimensions before you attempt to machine them. (I work as a design draftsman so am very critical of the quality of drawings) To produce workshop quality drawings costs thousands of dollars in drafting time which is not available for hobby projects. Do a web search for "Limits and Fits" which will give you tolerances for different applications. Can be a bit mind boggling at first if you do not have any engineering background. Fitting a shaft to a hole is normally on a Hole basis and the shaft machined to fit if you are making both parts but if using precision round bar off the shelf use a Shaft basis fit. Horses for courses as they say. Each application may be different but it is good practice to use the correct fit, not just make one part fit another.
Good luck with your project, Paul.
|Thread: Rotary table type?.......|
If you intend to use your 3 T slot lathe chuck on the rotary table it will have to have a matching number of slots. I have a 4 slot rotary table to match the 4 slots on my lathe chuck. Have a look at previous posts for rotary tables and my photos.
Edited By Paul Janes on 07/12/2013 10:21:04
|Thread: Rotary table inspiration....|
Your mounting plate can be larger than your rotary table. Just depends on how rigid it is.
I have a 6" rotary table on which I bolted a much larger plate. The plate locates on the centre spigot and is restrained by 4 countersunk cap screws and tee nuts. I then tapped some holes and used my mill clamps to hold the job.
Edited By Paul Janes on 05/12/2013 11:08:07
|Thread: Boiler materials/fabrication|
Model boilers in Australia are built to a code published by the Australian Miniature Boiler Safety Committee and is for steel or copper boilers less than 50 litre capacity and less than 100 psi. This code is more strict in some ways than the code for building full size boilers and written to ensure that miniature boilers are designed, constructed and operated to a high standard.
It enables amateurs to build boilers but every stage of its construction must be checked and signed-off by a certified engineer who is familiar with boilers. Amateur welding should be under the supervision of a qualified welder.
It states that carbon steel or carbon-manganese steel should be used for its construction.
Steel plate to AS 1548, Seamless steel tube to ASTM A 106, A 53, Heat certificates are required for all materials.
Copies of the code for either a steel or copper boiler are available from the Australian Miniature Boiler Safety Committee.
Edited By Paul Janes on 01/12/2013 10:02:55
|Thread: A Chuck and a Rotary table|
This is how I mounted a 6" 4-jaw chuck. Made a location spigot to centre the chuck and bolt directly to the rotary table. Centre location of the chuck on the table is not that critical as the job is centred with a DTI as long as it is secured soundly. A 4-jaw chuck is more accurate than using a self-centring 3 jaw and also allows the holding of odd shapes.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.