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



## EmilioG (Dec 30, 2014)

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

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


----------



## 18w (Dec 30, 2014)

Airplane parts or wheelbarrow parts? Drill vise or a finely machined kurt vise? If you do not have a vise that is parallel to your mill table with in tenths save your money. Imports, HSS tool bits, Starrett hardened and ground flat stock, or mill some up out of flat bar. These will get you with in tenths to a few thousandths  for a mere fraction of a $200.-$300.00 set. If on the other hand you need absolute precision Suburban Tool, Starrett, or old Brown & Sharpe parallels but we are talking aerospace quality now.

Regards
Darrell


----------



## randyjaco (Dec 30, 2014)

A $30 - $50 set should do fine for a hobby machinist. I bought a set for $50 from a retired machinist 20 years ago. It is the only set I have ever owned. I reground them once when I got my surface grinder a couple of years ago.

Randy


----------



## Mark in Indiana (Dec 30, 2014)

I bought a HF set for 22$, with coupon. They seem of good quality and mic out fine. I couldn't do better for the price, for my hobby needs.


----------



## mikey (Dec 30, 2014)

Thin parallel sets are 1/16" thick, while most standard sets come in either 1/8" or 1/4" thick. Absolute sizes are nominal. For example, a 1/2" pair may measure 1/2" tall +/- a few thou but each parallel in a pair of a given height will have been ground together and should be of identical height.

Unless you plan to do precision measurements with them an imported set will do fine for general work.


----------



## kd4gij (Dec 30, 2014)

I also have the HF 1/8" set. When I first got them I took them to work to check them out As we had a surface grinder if thay where out . But on a ferry large serface plate that had just been re certifyed thay where all within .0001 can't ask for much better.


----------



## rsegars (Dec 31, 2014)

EmilioG said:


> 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



This was a question I had to answer for myself. Just to become familiar with mills and lathes I was ok with just changing the shape of a piece of metal. One of my first projects was to mill a non standard 1911 front sight to match a non-standard rear sight that was on one of my pistols. I am on my 5th attempt but have found that I have had to use better and more accurate methods and aids to even get close to something I find acceptable.
So for me when I use the best, I at least know the fault is not in the equipment but rather in my own skills.


----------



## 18w (Dec 31, 2014)

18w said:


> Airplane parts or wheelbarrow parts? Drill vise or a finely machined kurt vise? If you do not have a vise that is parallel to your mill table with in tenths save your money. Imports, HSS tool bits, Starrett hardened and ground flat stock, or mill some up out of flat bar. These will get you with in tenths to a few thousandths  for a mere fraction of a $200.-$300.00 set. If on the other hand you need absolute precision Suburban Tool, Starrett, or old Brown & Sharpe parallels but we are talking aerospace quality now.
> 
> Regards
> Darrell



Emilio, I hope my above comments didn't come across as being a smart a$$. Doing the most accurate work you can is the basis of machine work whether you are a hobby person or a pro. There are all different kinds of needs and levels of accuracy however. The quality of imported parallels is remarkably good...yes there are some clunkers. This hobby can suck your wallet dry in a hurry and I think the average home shop guy can waste a lot of money "chasing tenths" when so many other factors such as the machines themselves, vises and inaccurate setups contribute to dimensional error. I don't want to dissuade you from buying quality tools but I think you would be served well with the imports. With the money saved keep your eye out for a retiring toolmaker, or there is a ebay seller who specializes in used tooling that he regrinds, and buy yourself a couple of different pairs of really fine, accurate parallels that you keep tucked away for those special jobs. Ultimately your imports may be just as accurate but there is also a sense of pleasure and pride using certain tools when a particular job requires the utmost in accuracy.

Regards
Darrell


----------



## stupoty (Dec 31, 2014)

I have a set of parallels that cost about £40 , their realy quite good and came in a nice box.

somone else pointed out that it all adds up, table, vice, parallels, head alignment etc.

i might cry if i ran a cutter into a £150 parallel 

Stuart


----------



## chips&more (Dec 31, 2014)

If you just need two pieces of metal at the same height to support your project. Then IMHO an import parallel set will me more than adequate. They will probably be ground in sets, so will be matched. BUT, do not expect them to be set/ground accurately at a nominal dimension. Now, if you want parallels and you want to do quantitative measurements with them, then dig into your wallet. If you want a ½” parallel to mike 0.500” it will cost you…Good Luck, Dave


----------



## invisabledog (Dec 31, 2014)

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 (Dec 31, 2014)

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. (Dec 31, 2014)

EmilioG said:


> 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 (Dec 31, 2014)

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 (Jan 1, 2015)

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 (Jan 1, 2015)

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


----------



## darkzero (Jan 1, 2015)

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 (Jan 4, 2015)

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 (Jan 4, 2015)

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 (Jan 11, 2015)

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.


----------

