Here is a list of all the postings James Veitch has made in our forums. Click on a thread name to jump to the thread.
|Thread: Motor Valves, What are they good for?|
I have a clapped out Briggs & Stratton motor. I've torn it apart to see what bits and pieces might be useful.
I'm sitting here looking at the shiny, bright valves wondering what I might do with them.
Most importantly is the steel machinable or am I asking for trouble?
Are there other good bits on the motor I should be looking to salvage?
Thanks in advance,
|Thread: What type of STEEL?|
A couple of things. Versaboss suggests a MEW article on steel types and metals would be a waste of time. To those who know, yes, to those who don't know, no. I'm not suggesting a comprehensive catalog of code numbers, I'm suggesting basic guidance for newbies. I guess the editor needs to decide what type of article will service the greater part of the subscribers.
The link to the RoyMech steel page given by Martin W is interesting but still confusing to a person of my experience. For example the term "silver steel" doesn't appear on that comprehensive list. I suspect terms like "silver steel" and many others that are bantered about are applied to a whole range of metal recipes.
Thank you Nigel McBurney for introducing a new term to me, i.e., gauge plate...???
A bit off topic but still in the ball park, Ramon mentions heat treating EN8 with "through hardening" and Chris mentions "direct hardening" EN19. Two terms I haven't heard of before. I'm still looking for a small book that tells me to do some simple examinations on a hunk of metal (like the geology field test) and then use it for and machine it within general parameters.
Now for a personal anecdote. My brother-in-law used to be a statistician for the metallurgists at the old BHP plant in Newcastle, Australia. He would relate how it was the devil's own nightmare to get any batch of steel within specifications. You just never start with a pot of pure Fe (iron) and you can never make it totally pure. So every batch of steel that rolls out the door is the best approximation given the raw materials that rolled in the door. To me that all made sense. Everyone is trying to do their best, but a good engineer examines the material at hand for compliance to specifications. I don't think that any given specimen of EN8 or EN...whatever completely meets all specifications. As a novice I'm interested in general classes of metals. How to define my metal need for a particular job, how to identify a generally suitable specimen, how to generally deal with that metal.
I once again thank all those who have made comments to my questions, you are helpful and I appreciate the time and thought you have given.
Yours, Jim V.
|Thread: Gear milling|
Thank you John and TomK that helps a huge bit. I do have Ivan's book and it is great.
|Thread: What type of STEEL?|
Thank you everyone for your contributions to this thread, and thanks David, I'm looking forward to the article in MEW.
The comments given above show that, even between experienced machinists, there is controversy, if not confusion. As a novice I am totally confused. Admittedly I pick up odd bits of steel where I can find them (due to cost) and try machining them. Some work and some eat up my tools and send shudders through my equipment. I guess what I would wish for in a MEW article would be some sage advice to KISS, keep it simple, if that's possible. I know there are a thousand spices but I'm just doing basic cooking. I'm reminded of the old "80/20 rule," that is 80 percent of the work is done by 20 percent of the workers. Is this true with engineering metals too? Like 80 percent of the time when making "X" a novice should use "Y" type steel so find some and stick to it till you gain some experience. Talking of experience I appreciate the advice given above on how to tell one type metal from another. That gives me something to look out for. In geology there is a well known set of field test used to identify what kind of rock you have in your hand. You start by trying to scratch glass, then scratch the rock with a pen knife, and so forth. Is there even a rough procedure used for metal. Example, step one: colour, step two: heft (is it heavier or lighter), three: is it magnetic, four: does it scratch deeply, etc.
Oh, well, just babbling, told you I was confused.
Once again thanks for all the very fine comments.
Please, a little clarity,
What are each of the following.
What does each of them look like (so I can tell them apart)
What is each type good for, or commonly used for.
What are the machining characteristics of each.
What is the rank, cost-wise, of each.
1. Cast iron
2. Carbon steel
3. High carbon steel
4. Bright steel
5. Silver steel
6. Stainless steel
7. Drill rod
8. High speed steel
9. Gun metal
Feel free to add any others that are commonly seen in the model engineer's workshop.
Thanks, Jim V.
|Thread: Gear milling|
Thanks for your contributions to this thread, I've found them interesting and helpful, however I have a question you might be able to help me with.
You make reference to two sources: "Gears and Gear Cutting", by Ivan Law and the web article at metalwebnews.com, "Cutting Involute Gears with Form Tools" by John Stevenson.
On page 114 of Law's book and in the Stevenson article there is a table to calculate dimensions for the cutting tool. Both authors claim their tables are for DP 1 and a Pressure angle of 20 degrees.
Trouble is the two tables do not match. Not even close.
So? Can you or anyone else sort this out for me?
Thanks in advance,
|Thread: Turbine Blades|
Thanks all for the many comments and ideas.
I may not have a turbine spinning yet but my head is spinning.
I will try to photograph and document my disasters and progress, if any.
From reading some of the suggestions I feel I should elaborate a bit on my idea.
This may help you visualize the problem and generate solutions.
The turbine is to go on the end of a swimming pool cleaning hose. The little turbine will have a central axle that will drive a gear set. The gears will drive a small toy vehicle along the bottom of the pool. (If you have kids or grand children you will know why this needs to be done.)
So, I will have lots of energy that I can deliver to the turbine because a pool pump moves a lot of water. I may even have to modulate the flow to the turbine so I don't over stress it, but that problem is way in the future. With so much water pressure I can suffer some blade inefficiency but part of the fun is to make things that are as nice as we can.
The pool hose inside diameter is nominally 45 mm or a little over 1 3/4 inch.
I'm not an engineer so I need to research things like: number of blades, pitches, everything.
The many suggestions given here by forum members has made me think (always a refreshing change). My goal is to make a small turbine. Milling a turbine is not my goal, but it might be one of several paths. Maybe some brass sheet, a tin snip, some silver solder and a brass hub is the better way to go.
I think it was Confucius who said, "If you have an expensive milling machine in your shed you are going to use it for the damnedest things."
Once again thanks to all, JV
Thanks, Windy, Ian and Kwil,
This is really a tough one with no obvious straight forward solution. I agree that there will have to be a lot of finishing file "artistry" involved.
From the dearth of replies I guess the world community of home engineers is looking at this post and gasping. Hope I get a few more wild and creative suggestions.
Thanks all. JV
Ok, I know this will be a bit vague and I apologize for that. I'm just looking for some general ideas on how to approach this problem.
I want to make a small water turbine.
The general design is a two inch diameter turbine that looks like a jet engine.
That is the water will flow through the turbine end-to-end.
The rotating center hub will have three to four blades extending from the center hub. These blades are to be pitched (imagine a short, stubby propeller blade).
The hub with blades will fit inside a tube.
Hope that's not too confusing.
So the problem is: How to mill the blades on a NON-CNC mill?
I'm not looking for perfection, just damned good enough.
Thinking about it for a moment I guess this question can be generalized to:
How would you mill a propeller? Same complex shape except I'm looking to make very stubby blades.
Thanks in advance for any thoughts you might have.
Yours, Jim V.
|Thread: Hexagon holes|
Thank you all for your fine suggestions. I appreciate them very much.
Yours, Jim V.
This one has me stumped.
I need to make some hexagonal holes in the center of small gears and wheels.
How do I accomplish that to an acceptable degree of accuracy?
I would like to be able to make holes of various sizes, mostly fairly small.
The only thing I can think of now is to drill a round hole and brutally gnaw out the hexagon "by guess and by golly". The results are pretty crude.
Thanks in advance, Jim V.
|Thread: How many Boiler makers?|
Sorry to say I don't know what "TC, KNH, LBSC" are. I do read so if they are reference books please elaborate. Thanks.
Greetings Tony, et al,
Does anyone have an Internet link to the AMBSC code (Australian Miniature Boiler Safety Committee part 1 - issue 7 : copper boilers?) It seems like this code is creeping in as the international standard, it certainly is the rule here in Australia.
It seems that boiler making is something like voodoo or black art. No body seems to speak of it in the light of day. When I ask "experienced model engineers" about boiler making the reaction is something akin to a 12 year old girl asking her father about sex. Lots of evasive answers and a quick drift to another subject. I was in a club for a while and there was a resident boiler inspector. He was just as vague but did once show me his oily and used copy of the AMBSC code. Now that I think about it he didn't offer to let me look inside it he just held it before me for a second or two and then it was gone.
ME an MEW are great magazines, have they ever done a series of articles leading a novice step-by-step through the process of making a boiler?
Anyways, good luck with your boiler project Tony and keep us posted on what you learn.
|Thread: Overseas Deliveries|
Hi Russell & Fred,
I'm from Ipswich, west of Brisbane. I've purchased both ME and MEW off the news stands for years. Finally got tired of missing issues.
|Thread: Opus Proximum|
I'm thinking of building the Opus Proximum engine. I'm a novice so excuse any of the following that's off base.
As a first step I'm modeling the Opus P. with a 3-D modeling program. This is proving to be a good exercise. First it makes me read the instructions carefully. Secondly it makes me look at the drawings carefully. Thirdly it makes me think about how I will actually go about making the real item.
I've already found several minor points of confusion or perhaps errors in the material as presented. That's all fair enough and not a big problem. The act of modeling on the computer has helped catch some of these.
I'm not finished modeling yet but here is what I've found so far:
1. The diagram titled: BASE PLATE, p. 23.
a. There are 4 holes shown to the right side of the plate. They are arranged in a rectangle of 5 mm by 22 mm. PHOTO 1 and the photo above PHOTO 1 show the holes are not in a rectangle. The diagram CYLINDER BASE (p.24) shows the 4 holes in a rectangle of 12 by 19 mm. The stated hole sizes also disagree, i.e.: 12BA to 10BA.
b. The photo of the finished item on p. 22 shows 4 additional hole are needed to mount the BASE PLATE to a wooden platform.
2. The diagram titled: MOTION PLATE, p.23.
a. The size and position of the rectangular hole are not specified. Is the size of 4 X 19 mm correct? Is the position from the top right corner as 11 mm down and 4 mm in, correct?
b. The distance between the holes in the two tabs on the right edge of the plate are not specified. Looking at the diagram CYLINDER p. 24 I believe the holes should be 19 mm apart. Is that correct?
|Thread: Overseas Deliveries|
Another Aussie here. I just subscribed to ME Workshop on-line. I received an email confirming my subscription but the email stated I would receive my subscription number by mail. It would be much nicer if I could receive my subscription number by email so I could immediately start benefiting from the web services. Would this be possible?
On another point, when I subscribed to MEW (two days ago) I also tried to subscribe to ME but got a message saying that that page "could not be found." I'll try again today.
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.