Parallels - what are the differences?

[Mayhem]

Ed, I think Bob positions them flat on the vise bed.

[EdK]

(08-26-2012, 10:01 AM)Mayhem Wrote: Ed, I think Bob positions them flat on the vise bed.

OK, so you would need a number of different diameters of bearing races to use depending on the width of your work piece. I think I get it now.

Ed

[f350ca]

I use HSS tool blanks quite often. They're ground perfectly straight and parallel, and I've managed to collect a good assortment of sizes from 1/8 to 1 inch.
On the bearing race, I have a large one, about 5 inches in dia I use to tram the mill. Again they're ground to closer specs than I can measure, lay it on the table and set the dial indicator to sweep it from the chuck. Full measure in one setup.

[Rickabilly]

If we are going to go into bearings as parallels, one that very few think of, is using the actual rolling elements themselves, if you can get a hold of an assortment of different large-ish bearings and knock out the cages not only can you use the inner and outer rings but you can use the rollers on end as fixed length spacers which is very handy when you are bolting down directly to the table and the work is an odd shape, within my capability to measure, all the rollers in a given bearing will be the same length, It is possible to use cylinderical rollers laying down also but only in the bottom of a vice. My favorite rolling elements are the Barrel shaped ones from self aligning roller bearings, they are just nice in your hands for some reason but the tapered ones out of tapered roller bearings are the most practical as one face being larger gives better stability while the smaller top face means that you've got less chance of the tool bumping into them as you break through.

I am partial to the use of HSS section too but I suppose my favorite set of parallels were a set made as a shaper exercise at tech college then hardened and ground, as it would happen the set I made were taken by mistake (or stolen) so as a form of compensation the teacher gave me the pick of the sets that weren't collected, while the ones I had made were really good (I came top of the class on that exercise) the two sets I ended up with were poorly machined before hardening and grinding, so the side reliefs and through holes are uneven but they are parallel and square and I have been using them for more than two decades and now they are just a part of my little collection of stuff, I can't imagine not having them around.

Regards
Rick

[SnailPowered]

My brother works for Sargent Controls and makes lots of bearings in my understanding. I may be able to get boxes of rejects. I will ask him.

[TomG]

Darren,

Most of my work is done with a set of 1/8" parallels. I also have a pair of 1/2 x 1's, 5/8 x 7/8 because they fit the T-slots, and several different heights of 1/4" parallels. I do have a set of the wavy type but rarely use them. A set of adjustable parallels is also handy for supporting the vise jaws (keeping them parallel), opposite a small part.

Tom

[Mayhem]

I recall reading somewhere that the metal strapping you see around packs of bricks is very useful in preventing parallels falling over or moving. Essentially, you cut a length and bend it a few times so it looks like a W or a wavy parallel. You then sit this between the parallels and it keeps them pressed against the vise jaws. It also compresses, so the jaws can be tightened.

I still haven't gotten around to buying any parallels yet but will probably pick some up when in the US or order off eBay. I'm not really in a huge rush, as I still have work to do to my mill. I certainly won't be buying the sets available locally, as there are only 3 choices: a 4 matched pair set for $99, a 9 matched pair set for $198 or a 9 matched pair for $319 They don't even list the sizes, other than the length (6" and 4").

[EdK]

I use my 1/8" thick set the most, by far.

Ed

[PixMan]

I also use the set of 1/8" thick parallels that my dad has more than any others.

In my toolbox is a "custom" set of 3 pairs of 1/4" thick x 10" long parallels that my dad had made in the toolroom where he once worked. Made more for a common "Bridgeport" vise with the 2" tall jaws, these are 1-5/8", 1-3/4" and 1-7/8" tall. From a retired Starrett guy I got another custom set of parallels, all Starrett No. 354's. Two pairs of 1/4" x 1", one pair of 3/8" x 3/4" and one pair of 1/2" x 1-1/4". The Starrett are accurate enough to use in grinding or inspection applications.

You can never have too many parallels. And it never fails that the one you need is the one you don't have so you end up with a Rube Goldberg solution. ;)

Oh yeah, I just remembered that no one seems to have mentioned the adjustable parallels. They are VERY useful for time when you need to put something in the vise that has an uneven bottom because you can make it the height you need as differential to the one used as base height.

They are also useful for measuring inside dimensions of wider grooves and recesses. Slide it open to fit the space, snug up the screw(s), pull it out and measure over it to get the dimension. I have two each of the Starrett No.154''s six available sizes (A, B, C, D. E & F), though I don't really know why I collected more than one each. ;)

[Mayhem]

Your Dad still has the equipment to churn out more accurate custom parallels. When is he taking orders?