Precision Parallel Set: How accurate do a set do I need?

[invisabledog]

I just picked up a 10 pair set of the 1/8 inch from Grizzley. They are very nice and appear to be the same set Shars sells on ebay. They were slightly more from Grizzley, but I saved shipping as I am 5 miles from the PA store. I'm just a novice, so they will be more that adequate for my needs.

 

[Andre]

I have a grizzly set, and measured them. I now know the surface plate I has used was WAY wonky, 5 thou or more out so I won't publish the results. But I can say they are all very close, and more than likely more accurate then the bed of your vise is parallel to the table )

 

[Bill C.]

I'm shopping for a good set of thin parallels. I see them on Ebay, Enco, etc...
The Brown and Sharpe set looks nice but pricey. I don't do too much ultra precision
milling/drilling, but whatever will make the parts better. How much do most
people spend on a set of 1/8" parallel sets? Does it make sense to spend $200-$300.00?
Thanks

Here is the thing with parallels doesn't matter who made them always mic them if you can before buying. I worked in shops that supplied them. They may appeared to be the same height but that doesn't mean they were.

Another tip buy a couple of feeler gages sets. The ones with removable blades are better. After you place the parallels in the vise then place a .002 blade between them and the part. Tap the part down with a soft hammer until all the blades are tight then you know the part is parallel to the bottom of the vise. I used to use strips of paper but they fall apart when wet. Good luck

 

[4GSR]

My first set of parallels were pieces of 1018 CRS flat bar in various sizes. Along with pieces of Rex 95 as needed. It worked for many years until the Asian stuff started hitting the market. Now I have all sorts of sizes now and they are harden and ground.

 

[Cadillac STS]

For that I would go lowest cost possible. If you find they are not to your spec just return them right away. 99% or higher chance they will be fine.

 

[EmilioG]

Thank you all. Very good advice from everyone.
I will start with a less expensive import set for now.
Enco or Ebay.

 

[darkzero]

I have a cheap China set. Although I like quality tools & I would like a quality name brand set I have been perfectly fine with the import set.

I had no idea HF sold parallels (thanks to those who posted), the same 1/8" set that I use the most. HF has 25% off today so I went a picked up a set for $22.50 + tax, can't be that! I'll measure them later & will report back.

 

[Ebel440]

The only problem I've seen with the cheaper parallels are that they may not be as hard as good ones and the sides are not flat. This doesn't really mean anything unless you smack them really hard then they can get dents from the vise or part depending on how hard the other surfaces are. The sides are sometimes not flat which just makes it easier to get chips stuck between them and the jaw. I would buy the cheaper ones myself but I don't have a mill at home. I've also used starret ground stock plenty of times but that could cost more then cheap parallels if you want multiple sizes. I've also just made my own from aluminum if I need a special size.

 

[coolidge]

I have a Kurt D688 so I opted for the Kurt Magnetic jaws and parallel plate set for $95.46 on a 20% off Enco sale. I keep getting burned when I buy the lower priced made in CHINA stuff. My CHINA test indicator just broke the other day after using it like maybe 8 times. I purchased a 'precision ground' 36" 1/4 inch thick steel rule with a stated accuracy of .001 yet it was bowed like .015. How many times do I need to learn the same lesson. China machines are getting pretty good, the rest of their stuff not so much. China is also on my .... list for manufacturing counterfeit Mitutoyo measuring tools.

 

[T Bredehoft]

I spent almost 30 years as a Journeyman Tool Maker in the Steelworkers and then a non-union shop making natural gas compressors. While I knew of the existence of ground parallels, I never saw them in use. In the steelworkers shop (usually machine repair) The standard parallels were 1/8 by 1 O1 steel, un hardened. When they got beat up, you sawed off another pair. During this time I made a trio of 1-2-3 blocks, not full inch size but all ground together. I still have a pair of 1/2 by 1 by 8" O1 stock that has a few nicks on it but is still usable. The tool room in the compressor factory was primarily making jigs and fixtures for items ranging from 1 7/8" by 5/8" to cylinders 36 inches in diameter., weighing in the neighborhood of 1500 lbs.

Parallels were used, but they were work supports, not part of the precision. We had no problems with machining items. If precision was needed to tenths we used a grinder.

This is not to say that parallels are not needed, but the degree of precision they imply is often not mirrored in the machines they are used on.