Parallel Sets?

[rcazwillis]

Help the ignorant out! I know this is a basic question, but I don't know the answer. Please laugh at will.

What do you use parallel sets for in machining? I understand they are different thicknesses and are the same height withing .00xx. How would I use them if I purchased a set?

[CNCadmin]

I use them for raising the piece I'm machining in the work vise.

[rcazwillis]

I saw a picture of someone using them to raise the piece off the table. Evidently, the intention was to all the tool to cut through the material without hitting the table. That makes sense, but I was thinking "Maybe there is more to these".

I still wonder "Why the different thicknesses? Wouldn't a standard size meet most all situations?"

[nervis1]

Uses are limited only by your imagination, most use them to set items flat in their vice by setting one up against the fixed vice jaw and one up against the moving jaw, the part goes on top, vice shut a little, give a little tap down with a soft hammer to seat the part in the vice, shut vice tight. Now the part is nice and flat and can be worked on, faced etc.

[DieGuy]

Actually not using a pair in a vise is completley wrong. The parallel tells you have the condition that their name implies. When tight against the work piece and vise base, the work piece is parrallel to the table of the machine, assuming everything else is correct like the vise is parallel to the table.

[psychomill]

I still wonder "Why the different thicknesses? Wouldn't a standard size meet most all situations?"

A couple reasons for this, among many. I have parallels ranging from .09 thick to I-beam types at 3/4 thick, at ranges of height from 3/8" to 3.0 inches. The thicker stuff I'll use for large or heavy pieces for example. The thinner stuff is nice for narrow work/clampings. Another reason is for example I'm machining on a 3/4 round bar in a vise. I might use a 1/2 thick parallel (just one) to lift the bar in the vise jaws for clearance. A little trickier if you're using 1/8" parallels.

I'll also buy (if not, grind my own) parallels that are not only precise in height, but in thickness as well. I'll use these as sort of make shift 'jo block' to lift set ups off of the tables.

[edbo68]

rcazwillis:
Like everyone said Parallel sets are typically used to raise a part a known distance while keeping it parallel to the table surface. As they are mostly used in a vise. The different heights allow you to bring the piece being machined above the tops of the vise jaws enough to do your machining.

Example: Lets say you have a 1 inch wide by 1/2 inch thick piece of steel (length doesn't matter) and you want to put the 1 inch width between the jaws of the vise to mill the top and to make it flat. But when you put your piece in the jaws of the vise you notice the jaws are 1-1/2 inch high. This is where the parallel set comes in. You find the right size parallel set and bring the piece above the tops of the vise. Now know the piece is supported properly, it's high enough to mill and parallel to the table. As NERVIS1 said you put one parallel on each side of the jaws of the vise. Plus should you need to drill any holes in the piece. You will have enough height to drill through without drilling into your vise and ruining it.

As for the Thickness: Its up to the kinda work you will be doing. 90% of the time you will be using the parallels in a vise. You wouldn't use a sledge hammer to nail in tacks.
If you have one of the small mills such as the Sherline or Taig, 1/8" inch thick is all you really need as you will be machining smaller material. So you can say its up to the size of the machine tools and material you will be using that will determine the thickness.


Hope this made sense. ;-)

Ed

[DareBee]

In relation to the parallels as well, I find that you can hardly have enough sets of 1-2-3 blocks. I use them for everything.
I also like my 2-4-6 blocks.

[rcazwillis]

Originally Posted by DareBee In relation to the parallels as well, I find that you can hardly have enough sets of 1-2-3 blocks. I use them for everything. I also like my 2-4-6 blocks.

Since this thread is about coaching the ignorant , tell me a bit about how you use the 1-2-3 blocks. I can see very similiar uses for these blocks. Such as anchoring the material to the table in an elevated position.

Ed,
Makes good sense. Thank you.

Everyone,
YOU GUYS ROCK! Thanks for the free flowing information. I bought a set on Ebay last night for cheap. Looking to get an anchor set and the 1-2-3 blocks.

[psychomill]

tell me a bit about how you use the 1-2-3 blocks. I can see very similiar uses for these blocks. Such as anchoring the material to the table in an elevated position.

Yep.... I'll use 123 blocks and 246 blocks (+1 Darebee) in much the same way. In addition to this, I might use it to also pick up work offsets against ( like picking up a machined surface underneath a flange on a cast part), use it to set tool lengths or even to lift fixturing (ie: clamp down an angle plate on them for taller parts).



They also make nice paper weights, wheel chocks for your tool box, use as a "skipping stone", endmill/drill holder, pencil holder, counter weight, fishing weight, hammer,.....

[Mcgyver]

my favorite use is as el cheapo red toolbox draw warpers

here are a couple of draw warpers. The two smaller ones, (4x4x3) are made by yours truly, matched, case hardened and ground square all over to a tenth.

a handy use is when you have an awkward shape requiring multiple ops in the mill on different surfaces. Figure out how to hold it once on one of these and then you can just rotate the block in the vice to get at other planes. pick up the edge of the block to for dimension control. Like many things in our drawers, they have a low duty cycle but when needed can be just thing!

[DareBee]

My reply is worthless, because all of you guys have the RIGHT answers!