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I have yet to tool up my mill, as I have other things requiring my time and money but one of the items on my list is parallels.
Now I see them in a variety of widths from 1/2" to 1/8" and what are described as 'ultra thin' and also wavy. So what is the difference?
And yes, I know that the difference between 1/2" and 1/8" parallels is 3/8" but this isn't what I am asking!
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Mayhem,
The wider the parallel, the more support you have under your part in the machine vice. But it would be impossible to support a piece of stock 3/4"" wide using a pair of 1/2" parallels. You would end up clamping the parallels in the vice but not the part.
Ultra thin parallels are for supporting ultra thin stock between the vice jaws.
The wavy parallels allow you to use a single parallel to support your stock. Because of the "wave" they will stand up on their own without falling over, and they will compress (flatten out) as the vice jaws are closed together so you can still clamp onto the work piece.
I think..... 
Willie
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The ultra thin ones are also good if you need to drill a hole that is close to the edge of the work piece. Soft-jaws would also be good in that situation.
Ed
For someone just starting out, a set of 1/8" thick parallels are the most versatile.
Not too flimsy so that they bend and will cover most sizes that need supporting.
When you get to needing others, then a 1/32" set and a 1/4" set, plus a pair of 1-2-3 blocks will cover almost everything you need to do.
John
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(04-22-2012, 12:36 PM)Bogstandard Wrote: For someone just starting out, a set of 1/8" thick parallels are the most versatile.
Not too flimsy so that they bend and will cover most sizes that need supporting.
When you get to needing others, then a 1/32" set and a 1/4" set, plus a pair of 1-2-3 blocks will cover almost everything you need to do.
John
I totally agree John. I have both 1/8" and 1/4" and use the 1/8" by far the most. I do need to get a set of the 1/32" since I've had a number of occasions where they would have been very useful.
Ed
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But don't rule out the wavy style, I was bought a set for Christmas one year and while I appreciated the gesture I thought they were a bit useless, 4years on, I have used them a load of times and they often have saved me where few options were available. So while they are not suitable for heavy work and you will need others they might be able to do everything a 1/32" set will do without being limited to just that single size.
Also, one of the old tricks for supporting work on the very edges is to use "stacked" parallels for example;
If you need to drill within 1/8" of the edge of some work but don't have any parallels thin enough to support the edge instead use 9/16" wide parallels on bottom then sit 1/2" parallels. On top of these clamping the work between the 1/2" pair this way you can safely work within 1/8" of the supported edge and don't have to deal with flimsy or very thin parallels that I find tend to fall over when loading up the work.
If you do need to use really thin parallels and they do keep toppling over, a little dab of grease works wonders to hold them onto the vise jaws, never get the grease on the top or bottom as this will hold swarf reducing accuracy, just a dab on the side face and then squish it up against the vise jaws
Whatever it is, do it today, Tomorrow may not be an option and regret outlasts fatigue.
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One good thing about thick parallels is they are like 2 parallels, as in, on edge or on the flat.
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(08-25-2012, 03:15 AM)Rickabilly Wrote: Also, one of the old tricks for supporting work on the very edges is to use "stacked" parallels for example;
If you need to drill within 1/8" of the edge of some work but don't have any parallels thin enough to support the edge instead use 9/16" wide parallels on bottom then sit 1/2" parallels. On top of these clamping the work between the 1/2" pair this way you can safely work within 1/8" of the supported edge and don't have to deal with flimsy or very thin parallels that I find tend to fall over when loading up the work.
Excellent tip! Thanks Rick.
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Front wheel bearing races from the local auto-bodgers, usually free for the asking. It supports the workpiece in the center so you can work all around the edges. That said, I use the 1/8" set for most work on a BP clone, and a short 3" set like Starretts on my small horizontal. They are 1/8 x 5/8, 3/16 x 1/2, and 5/16 x 3/8, in pairs.
Regards,
Bob
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(08-25-2012, 11:26 PM)bobm4360 Wrote: Front wheel bearing races from the local auto-bodgers, usually free for the asking. It supports the workpiece in the center so you can work all around the edges.
Regards,
Bob
Bob,
I'm not visualizing how the bearing races are supporting the work. It seems to me the work would rock on the curved edge of the bearing race. 
Ed
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