2017 POTD Thread Archive

Billh50 said:
While I was turning down more of the spindle yesterday. Yep, you guessed it. I decided to make a change on the design. It's been a while since I designed anything and I guess I forgot a few things.
Made me wonder how many people change things from their original design as they go along.
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My most frequent modus operandi for stuff I do for myself is to design it (either on paper, CAD, or whatever) to something like the 80%-95% level, then take care of the fine details during machining. If necessary (documentation, an article, etc.) I'll modify/correct/update the design to reflect the "as built" features.

It's a quick and efficient process. I suppose I'd get more formal and systematic if it were for a "paying customer."
 
Alas, years of working with the design control requirements of ISO 9000 companies have etched the process on my brain. In a large corporation there is benefit in reviewing and freezing a design fairly early in the process. There are usually a large number of people involved in the project and everyone has to be working towards a common goal. For the home shop, the benefit is less noticeable since it is usually a committee of one for the design review.

I have been working with CAD for some twenty years and find it easier to do my "sketching" with CAD. Prior to that, I had done all my sketching on paper. Paper works well for simpler projects but I have found that it can be a problem when trying to visualize how more complex assemblies go together.

An example comes to mind. Some twenty five years ago, I decided to make a new trailer for my boat. I had been pulling my boat home when a semi passed me on a divided highway, clipping the corner of the trailer in the process. The trailer started to fishtail and I came to a stop with the boat off the trailer, laying on its side on the shoulder and the trailer upside down with the tongue under my truck. I managed to get the trailer upright and winched the boat back on and limped home but decided that I needed a new trailer.

The idea was to add braking capability and to drop the axle to lower the center of gravity and decrease wind resistance. A description of the project is in post 72 in this thread. http://www.hobby-machinist.com/threads/show-us-your-welding-projects.23505/page-3

The finished trailer is a piece of work that I am proud of to this day. It has nice lines, it's functional, with Surge disk brakes and the low rider profile, I barely know it's there. However, there is one flaw which I didn't discover until I began using it. I had dropped the axle too far. On a level road, there was no problem but pulling up a short incline as into a filling station, the rear end of the trailer dragged on the pavement. I was able to shorten the shackles and raise the bed about an inch but it really needed more.

The moral of the story: had I been using the CAD that I now use, I would have had a fully assembled model where I could have better foreseen the dragging issue and designed a 3 or 4 inch drop. Designing in CAD forces one to think in detail about the project which, IMO, better distills the idea and results in a better design. To be sure, there is a learning curve; something that I'm dealing with right now in trying to learn Fusion 360 but if I had to do it over again, I would have started working with CAD sooner.

Besides, I never could sketch all that well.
 
And I'm just now trying to figure out sketchup. I too am old school pencil and paper, having a hard time with this but I know I have to stick to it and keep playing with it till I figure it out.
 
9 people from our local hobby metal workers group got together and bought about 9000 LBS of 4140 and 4340 annealed steel from a local oilpatch business that didn't survive the economic downturn. Here's a pic of part of our haul.

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We came away with 13 4140 logs that are 6" diameter X 4 feet long. a whole bunch (about 40) of 1 foot long 4" round pieces, a bunch to 3 foot lengths of 4" rounds and a bunch or 5" rounds with a 1" hole in the middle about 3 feet long. My personal take was 5 of the 1 foot long 4" pieces, 2 of the 3 foot long 4" pieces, 1 of the 5" by 3 foot rounds with the hole and one of the 6" by 4 foot long logs.

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The 6" by 4 foot log is not in my garage yet, I'll pick it up in the near future. I'm not sure what I'm going to do with all this but for $45 and an evening of work to load it all I couldn't say no. It was a lot of work to load it all but we got it done with 7 pickup trucks, 2 engine cranes and 9 people and no injuries. The 5" round on the floor weighs about 250 LBS and the 6" by 4 foot ones are about 550 LBS.
 
Great haul, GREAT price! Of course, if it were me, things could get a lot more expensive very quickly ... neither my mini-mill nor my 9x20 lathe are in any way capable of handling such stock, nor is my 4x6 bandsaw large enough to cut usable rounds. So I'd have to tool up big time!! But I can drool, can't I? :drool:
 
What a haul John !! Oh by the way you deserve a huge YOU SUCK over that one. There's times I wish I was still in contact with the oil field but after 25 Alberta winters I can honestly say you deserve the good deal for having to endure the winters there.

Greg
 
Thanks guys, I'm resting tonight with a heating pad on my back! About a month ago I bought a 1" slice of 6" round 1018 cold rolled from Metal Supermarket for about $50 so we got an amazing deal. The owner of the business said a scrap metal dealer had offered 5 cents a pound. We paid 7 and he was happy to get it. A lot of people around here are falling on hard times right now. I work as an instructor at a trades school and we just got notice today that 56 trades instructors are getting laid off. Thankfully my job is safe, for now.
 
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