Will this work for parallels?

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tonydi

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I recently bought a new 3" toolmakers vise and the jaw depth is larger than the old vise I had. I have a set of 3" parallels that I've used for years but the largest one is 7/8" tall. Since I often mill pretty small parts I really need a pair of taller parallels. I could buy a full set of 6" ones but I couldn't use about a third of them because they're taller than the vise jaws. Seems like a waste of money.

I've searched around and people talk about making their own but I don't have access to all of the processes outlined (hardening, surface grinder, etc). But I did see a couple of people talking about just buying ground stock and cutting it into pieces.

Here's a piece of O1 ground steel in 1/8" x 1".
https://www.mcmaster.com/9516K47-9516K213

Would this work, would these be easy to cut with a bandsaw or Dremel cutoff wheel? I'm not sure I really need them to be hardened but I would like them to at least be as accurate as the parallels I currently have.
 
You could always just put some key stock or whatever you have below your existing parallels to raise them up .
 
One option you might consider is to buy a set of ultra-thin parallels in 6" length. These go up in 1/16" steps, which is super-handy when you need to position a part precisely. You could use your 3" parallels for most work and use the taller ones as needed from the thin set. These thin parallels also allow you to drill very close to an edge, which can be a major advantage at times.
 
mikey said:
One option you might consider is to buy a set of ultra-thin parallels in 6" length. These go up in 1/16" steps, which is super-handy when you need to position a part precisely. You could use your 3" parallels for most work and use the taller ones as needed from the thin set. These thin parallels also allow you to drill very close to an edge, which can be a major advantage at times.
Click to expand...

Thanks, Mike, but that is less cost effective than the smaller sets I was talking about because almost half of the parallels will be taller than the vise jaws.

I really just need one pair of 1" and I'd be set, especially considering that I've gotten by with only 4 pairs in all the years I've had the mill.

@mmcmdl I actually tried stacking another pair of parallels under my 7/8" pair. I ran into two problems. One, the first time I needed to do that the part I was machining was thinner than the width of my smallest parallel so I couldn't close the vise jaws enough. If I had some smaller material that was close enough tolerance not to affect the milling operation I'd still run into the problem that anyone who has used one of these screwless vises knows all about. It's a bit of work to get everything situated and get the moveable jaw into a position that clamps properly. When I was able to stack another parallel underneath the 7/8" parallels they kept wanting to fall off or tip over. Too many moving parts and not enough hands! :D

@hman Thanks for that. I've used W1 and it's easy to cut but didn't really know about O1. The specs say that ground bar is +/- .001, which isn't all that good compared to the .0002" typically called out for parallels. But I was thinking maybe that spec is for the 1/8" thickness and not width. I'll need to check that out.

(Edited to add) Oh shoot, I just saw this Width Tolerance 0" to 0.005". Now if that's just how far it might vary from 1" on any particular bar, like one bar might be 1.000 and another 1.003 or 1.005, that's fine. What I don't know is the tolerance on the parallelism.
 
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I have a set of thin parallels like Mikey suggests, I'd be quite lost without them. Definitely worth an investment even if you don't use some of them. I quite often use the larger ones on their sides as thin packing shims in setups, they're really handy.
 
If you buy 12 inches of 1/16 by 1 inch O1 flat stock, and cut it in half, the two ends will be the same witdth.
 
@tonydi,

I believe that "Width Tolerance 0" to 0.005" " is over the entire 18" bar.
Any 3" section you cut from it will be way better than that.
I think your first suggestion/question is the best solution.

-brino
 
Reading this thread has me thinking how handy it would be to have a custom set of parallels . Since I don't have a surface grinder could I just set the steel in a vice and machine them to the size I wanted , wouldn't have as nice of a ground finish but should be able to get them parallel by milling correct ?
 
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