Best way to fabricate multiple metal parts?

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jon price
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Best way to fabricate multiple metal parts?

Postby jon price » Fri Apr 22, 2016 11:01 am

I need to fabricate slide bar brackets for three similar locos. What is the best way to fabricate these given that I am looking to make six identical parts?

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barhamd
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Re: Best way to fabricate multiple metal parts?

Postby barhamd » Fri Apr 22, 2016 1:09 pm

Draw up in a CAD package and then get PPD to etch them?
David

Winander
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Re: Best way to fabricate multiple metal parts?

Postby Winander » Fri Apr 22, 2016 1:47 pm

Jon

I'm not certain what slide bar brackets are, but could you solder them together? A spell in the oven once complete would ease separation.
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essdee
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Re: Best way to fabricate multiple metal parts?

Postby essdee » Fri Apr 22, 2016 1:48 pm

What form do the brackets take, Jon - a casting, or fabricated? For a simple cast type, I have made up a pair of brackets as soldered laminates and then added NS strip to give each bracket 'depth'. For six of a relatively simple shape, I would be inclined to make up two sets of three soldered laminates and then add detail? Matching the two sets should not be too difficult? (And if you find some clown with a vernier running from side to side of one of the completed locos, well......)

CAD/etch would certainly deal with more complex shapes and save time, unless you need them in a hurry. Horses for courses....!

Best wishes

Steve

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jon price
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Re: Best way to fabricate multiple metal parts?

Postby jon price » Fri Apr 22, 2016 3:04 pm

Well I can't do CAD, and I think the cost of etching for just six components might be a bit much. Soldering the sheets together and then cutting them out and desoldering sounds like the best option. I agree that nobody will see both sides together so making two sets of three sounds reasonable. They appear to be a simple plate and not a complex casting so I'll just have to get the piercing saw out and break a few blades. (I know, go slowly to avoid breaking blades, but..)

Thanks for these suggestions.

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Re: Best way to fabricate multiple metal parts?

Postby garethashenden » Fri Apr 22, 2016 3:41 pm

jon price wrote:Well I can't do CAD, and I think the cost of etching for just six components might be a bit much. Soldering the sheets together and then cutting them out and desoldering sounds like the best option. I agree that nobody will see both sides together so making two sets of three sounds reasonable. They appear to be a simple plate and not a complex casting so I'll just have to get the piercing saw out and break a few blades. (I know, go slowly to avoid breaking blades, but..)

Thanks for these suggestions.


It's not so much going slowly that prevents broken blades, it's having the blade properly tensioned. You may know that, but lots of people don't. Put the blade in one end and tighten it, then put the saw handle up on a table and push down, curving the frame. Then tighten the second end of the blade. The frame will then put tension on the blade and it will cut much more easily and with fewer broken blades.

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Tim V
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Re: Best way to fabricate multiple metal parts?

Postby Tim V » Fri Apr 22, 2016 4:07 pm

Techniques covering this are explained in Guy Williams book on constructing locos, the first edition by Ian Allan is better than the later Wild Swan books for this. I would, of course, suggest all three books should be on your bookshelf.
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Re: Best way to fabricate multiple metal parts?

Postby dal-t » Fri Apr 22, 2016 4:54 pm

garethashenden wrote:Put the blade in one end and tighten it, then put the saw handle up on a table and push down, curving the frame. Then tighten the second end of the blade. The frame will then put tension on the blade and it will cut much more easily and with fewer broken blades.


Only necessary if you have a frame that doesn't allow you to increase the tension once the blade is fixed - the adjustable type is much easier to handle (oops!) and well worth the extra investment, in my experience. Two other 'tricks', select the grade of blade to match the thickness of the metal (or angle the cut so that more teeth are in contact), and lubricate regularly, a beeswax stick works well for me. There is one other way to improve your technique, but it's a bit extreme - spend some time doing intricate fretting of sterling or fine silver; the softness of those metals make it's much 'harder' (more difficult!) to cut cleanly, so when you go back to brass or 'german silver' the easier cut in the harder material comes as a real delight!
David L-T

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jon price
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Re: Best way to fabricate multiple metal parts?

Postby jon price » Fri Apr 22, 2016 8:52 pm

All good advice thanks! All I have to do now is draw the parts as there are no plans, just a couple of oblique photos. I thought I would follow the "stick the plan to the metal" method rather than the more engineeringy marking out approach. Just need to work out which glue to use.

I have Ian Rice's three Wild Swan books, plus the 1948 edition of John Ahern's Miniature Locomotive Construction

I have called the parts I am looking to make "slide bar brackets" after looking at one of Ian Rice's drawings. I see that Ahern calls them "crosshead guide yokes" and says that they are rarely illustrated on plans so he had to make a best guess as I do. He also says that cylinders can usefully be made of wood and paper, an anathema for the modrn day purists who say locos must be made of matel, but it worked for him so..

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Jim Summers
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Re: Best way to fabricate multiple metal parts?

Postby Jim Summers » Sat Apr 23, 2016 8:10 am

Jon,
Regarding cylinders, if you find your way to the Forum of the Caledonian Railway Association Scalefour Society and find the thread on building a '262' ST class

http://www.crassoc.org.uk/forum/viewtopic.php?f=8&t=804

you will find how Alan Kirk does his fine work using somewhat more modern materials such as printed circuit board. It's developing into a very useful thread, and as it's Caledonian, even better.

Jim
Last edited by grovenor-2685 on Sat Apr 23, 2016 8:42 am, edited 1 time in total.
Reason: Corrected, I hope (Red being new, green-deleted) Rgds, Keith

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Re: Best way to fabricate multiple metal parts?

Postby billbedford » Sat Apr 23, 2016 8:57 am

dal-t wrote:
garethashenden wrote:Put the blade in one end and tighten it, then put the saw handle up on a table and push down, curving the frame. Then tighten the second end of the blade. The frame will then put tension on the blade and it will cut much more easily and with fewer broken blades.


Only necessary if you have a frame that doesn't allow you to increase the tension once the blade is fixed - the adjustable type is much easier to handle (oops!) and well worth the extra investment, in my experience.


Never used an adjustable saw frame when I was making a living with a piercing saw. To tension the blade you rest the frame against the edge of the bench and the end of the handle in your belly just below your sternum and lean forward slightly. This bends the frame enough to set the tension and leaves both hands free to manipulate the blade and nuts. When properly tensioned the blade should give a clear ringing note when plucked.
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Will L
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Re: Best way to fabricate multiple metal parts?

Postby Will L » Sat Apr 23, 2016 9:34 am

billbedford wrote:Never used an adjustable saw frame when I was making a living with a piercing saw. To tension the blade you rest the frame against the edge of the bench and the end of the handle in your belly just below your sternum and lean forward slightly. This bends the frame enough to set the tension and leaves both hands free to manipulate the blade and nuts. When properly tensioned the blade should give a clear ringing note when plucked.


Still looking for that LIKE button. That's how you work a piercing saw.

I also agree the basic method. Laminate the lot with solder. Cut once with a piercing saw which is relatively easy because you have a good thickness to go at . Square off to the right shape by file before de-laminating. You will get 6 identical items well within an evenings work which is more than you can say for the draw and etch method. Not that I've anything against using etchings where appropriate, there are lost of things I wouldn't want to tackle with a saw, but for small numbers of relatively simple items the old ways still have much to recommend them.

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Re: Best way to fabricate multiple metal parts?

Postby dal-t » Sat Apr 23, 2016 5:11 pm

billbedford wrote:To tension the blade you rest the frame against the edge of the bench and the end of the handle in your belly just below your sternum and lean forward slightly.


Sounds appropriate for some sort of hair-shirt ceremony, but I'm not sure of the utility at the workbench. Personally, if there's an easier and more reliable way of doing something I tend to adopt it - but I realise that may deprive some people of a certain bizarre satisfaction. Each to their own!
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James Moorhouse
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Re: Best way to fabricate multiple metal parts?

Postby James Moorhouse » Sat Apr 23, 2016 5:51 pm

dal-t wrote:
billbedford wrote:To tension the blade you rest the frame against the edge of the bench and the end of the handle in your belly just below your sternum and lean forward slightly.

Sounds appropriate for some sort of hair-shirt ceremony, but I'm not sure of the utility at the workbench. Personally, if there's an easier and more reliable way of doing something I tend to adopt it - but I realise that may deprive some people of a certain bizarre satisfaction. Each to their own!

This method has previously been described on the Forum here. It seems to be a common approach for those that use a piercing saw to make a living.
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John Bateson
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Re: Best way to fabricate multiple metal parts?

Postby John Bateson » Sat Apr 23, 2016 7:36 pm

Would this do.jpg
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Will L
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Re: Best way to fabricate multiple metal parts?

Postby Will L » Sat Apr 23, 2016 9:09 pm

dal-t wrote:Sounds appropriate for some sort of hair-shirt ceremony, but I'm not sure of the utility at the workbench. Personally, if there's an easier and more reliable way of doing something I tend to adopt it - but I realise that may deprive some people of a certain bizarre satisfaction. Each to their own!


Don't knock it till you've tried it, you may just find that there isn't any easier or more reliable way of doing it.

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Re: Best way to fabricate multiple metal parts?

Postby billbedford » Sun Apr 24, 2016 10:14 am

dal-t wrote:
billbedford wrote:To tension the blade you rest the frame against the edge of the bench and the end of the handle in your belly just below your sternum and lean forward slightly.


Sounds appropriate for some sort of hair-shirt ceremony, but I'm not sure of the utility at the workbench. Personally, if there's an easier and more reliable way of doing something I tend to adopt it - but I realise that may deprive some people of a certain bizarre satisfaction. Each to their own!


It's the way I was taught and most of my teachers were, or had been, professional jewellers or silversmiths.
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jon price
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Re: Best way to fabricate multiple metal parts?

Postby jon price » Sun Apr 24, 2016 11:26 am

I'm with Bill and Will on this. There is usually a reason that traditional approaches work well, and, unless some aspect of the technology has changed drastically, continue to.

The traditional way uses compression to load the blade which when released is under tension. The adjustable type requires the user to provide the tension directly by pulling the arms of the frame apart, a less efficient and less effective approach.

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Re: Best way to fabricate multiple metal parts?

Postby martinm » Sun Apr 24, 2016 3:52 pm

I'm with Bill and Will on this. There is usually a reason that traditional approaches work well, and, unless some aspect of the technology has changed drastically, continue to.
The traditional way uses compression to load the blade which when released is under tension. The adjustable type requires the user to provide the tension directly by pulling the arms of the frame apart, a less efficient and less effective approach.


But is it not possible to apply tension in the same way on an adjustable frame?

martin

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Will L
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Re: Best way to fabricate multiple metal parts?

Postby Will L » Sun Apr 24, 2016 9:11 pm

martinm wrote: But is it not possible to apply tension in the same way on an adjustable frame?


Most piercing saw frames are adjustable. This to accommodate different lengths of blade. Typically when you brake one, there is often a bit which is quite long enough to reuse. You still tension them in the traditional way. I would have though it was quite hard to get enough tension on the blade using the adjuster, and a blade which isn't tight enough is much more inclined to break.

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Re: Best way to fabricate multiple metal parts?

Postby Terry Bendall » Mon Apr 25, 2016 7:08 am

martinm wrote:But is it not possible to apply tension in the same way on an adjustable frame


Yes it is, and that is what I have always done. I have an adjustable saw frame and my practice is the adjust the movable part so it is in the appropriate place to take the broken blade, then tighten the adjusting screw. Rest the fixed end of the saw on the edge of the bench, push onn the handle end and then do up the blade clamping screw.

This method of tensioning both fixed and adjustable saw frames is confirmed in a very old reference book on silversmithing - The Silversmith's Manual by B Cuzner which despite being first published in 1935 is still available as a re-print. A useful tip in the book, which I have not noticed before, is to rub a small amount of wax on the blade to help the cutting. The type of way is not specified but candle wax would do the job.

Terry Bendall

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Andy W
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Re: Best way to fabricate multiple metal parts?

Postby Andy W » Mon Apr 25, 2016 11:47 am

All very interesting. I assume that the tension slackens when the user bends forward with it pinned in his chest? What circumstances suit a slacker blade? I always try and keep the blade as tight as possible. I'm obviously missing a trick.
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grovenor-2685
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Re: Best way to fabricate multiple metal parts?

Postby grovenor-2685 » Mon Apr 25, 2016 12:28 pm

The process is to de-tension while putting the blade in or out, not when using it.
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Andy W
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Re: Best way to fabricate multiple metal parts?

Postby Andy W » Mon Apr 25, 2016 2:10 pm

Ah! Thanks Keith.
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Re: Best way to fabricate multiple metal parts?

Postby Winander » Wed Apr 27, 2016 9:36 pm

Another tip is to let the saw do the cutting, as my grandfather told my father etc etc "you just move the saw back and forth". It is pointless putting any downward pressure on the blade to assist cutting, let the teeth do that, just move the saw in the right direction. I first used a piercing saw last week and beforehand, after reading this forum (does that make sense??), wondered how many blades I would break. The answer was none.

One thing I did have a problem with was distinguishing different 'sizes' of blade. I bought a packet of various sizes but they all look the same to me. Is it just the teeth per inch that differs? I was expecting some blades to be bigger.

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Richard


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