Thread: 1-2-3 Blocks as Parallels?

Hi all,

I just purchased a pair of these:
eBay Australia: Buy new & used fashion, electronics & home d

I intend to use them for setting up, usual stuff but I also intend using them as a cheap pair of parallels. Would I be incorrect to use them as parallels non critical set ups such as using them as spacers when placing workpieces on the mill vice to ensure even height when clamping?

Or, to rest the machinists level on when leveling the bed of my lathe?

They claim to be matched to 0.0002" I would have thought this to be good enough for most of my work? I can also verify this with a DI on my tiny surface plate when they arrive. Perhaps some hand scraping will be needed?

Thoughts?

Cheers,

Simon

Ray bought a similar matched set a few years ago and they needed a little time on the surface grinder but they were pretty close.

-Josh

Hi Simon,
I bought a stack of those and sold some on here in Aus. I have never actually measured those particular ones, but they came in the same packaging as the ones from CDCO i also have. 3 out of 4 of those are "OK" but one is out woefully. More than good enough to use as parallels but for your level, make sure you always use the same ones the same way round......
They are pretty hard i don't know how you would go scraping them.

Cheers,
Ew

On edit, have they been posted yet? you could probably add a set of 6" parallels to the box for little or no extra postage charge. The sets are about $25

They should be fine Simon, just measure them up when you get them.
I bought a bunch of metric ones off him and some how got free postage for the box full

Like said above get yourself a set of parallels, they are just too handy not to have.

Dave

Thanks guys. I ordered the items over the weekend so they would not have processed the order yet I wouldn't think. I just sent them an enquiy about combined shipping. $25 for parallels is a great price but $65 shipping negates that!

Cheers,

Simon

I am sure for the close tolerance work you will be achieving from the back shed with the high procission machinery you are using it should be fine.
If you are looking for something to scrape get a bit of steel bar or cast,give it a few love taps with a hammer and knock your self out with scrapeing that.

Originally Posted by Brobdingnagian

Ray bought a similar matched set a few years ago and they needed a little time on the surface grinder but they were pretty close.

-Josh

The ones Josh is referring to that I got were these...Ultra Precision 123 Block 1-2-3 Blocks Set Plastic Case | eBay

And they were more than accurate enough for milling setups.

I bought some others second hand on ebay, together with some angle plates, the seller shipped the whole lot rattling around loose in an oversized cardboard box...

Regards
Ray

Originally Posted by pipeclay

I am sure for the close tolerance work you will be achieving from the back shed with the high procission machinery you are using it should be fine.
If you are looking for something to scrape get a bit of steel bar or cast,give it a few love taps with a hammer and knock your self out with scrapeing that.

wow

Hi Simon,
Without wanting this to sound to negative its a bit like asking "Can I use a spoon as a knife?" Sure it will work sometimes, other times not so much.

They will work when their size suits. Mostly their height 1" v the height of the jaws of your vice. IF your jaws are 40mm high the thinnest work you can hold is about 15mm thick. Of course the width of the work has to be more than 2".

I bought a pair that turned out to be not much of a pair, the seller replaced them.

Stuart

p.s. They are damn handy things to have around when you arent using the vice though.

Originally Posted by pipeclay

I am sure for the close tolerance work you will be achieving from the back shed with the high procission machinery you are using it should be fine.

Thanks PC....... I think

Naaa. I know exactly what you mean and I tend to agree with you on that one. It's no use in kidding yourself!

Hi Stuart,

I see what you mean. Had not thought about the dimensional limitations, I only pictured their use on workpieces that are longer than the width of the jaws and have them sitting either side of the vice.

On a side note, does it really matter if you have imperial or metric parallels? I mean are they mainly used as a comparative reference to ensure both sides are the same or is there sometimes the need to rely on their actual height and width in your machining calcs?

Cheers,

Simon

Originally Posted by RayG

The ones Josh is referring to that I got were these...Ultra Precision 123 Block 1-2-3 Blocks Set Plastic Case | eBay

And they were more than accurate enough for milling setups.

I bought some others second hand on ebay, together with some angle plates, the seller shipped the whole lot rattling around loose in an oversized cardboard box...

Regards
Ray

Had the same deal with a beautiful precision indexing device shipped with bits loose in box travel and momentum sprung the nice dovetailed box and marred all the precision surfaces grrrrrrrrrrrr response from seller ''stiff......'' Know the hurt Regards John. ps if ever buy anything like this it is insisted to take care with the packing.some of these sellers got no idea what they have and how it fits our picture.

Originally Posted by simonl

Hi Stuart,

I see what you mean. Had not thought about the dimensional limitations, I only pictured their use on workpieces that are longer than the width of the jaws and have them sitting either side of the vice.

On a side note, does it really matter if you have imperial or metric parallels? I mean are they mainly used as a comparative reference to ensure both sides are the same or is there sometimes the need to rely on their actual height and width in your machining calcs?

Cheers,

Simon

It doesn't matter at all. What matters is the parallelism and that the pair are exactly that, a pair. In that regard I find the cheap ones of tighter tolerance than the 123 blocks from the seller you listed anyway.
Cheers,
Ew.

Originally Posted by simonl

On a side note, does it really matter if you have imperial or metric parallels?

I'm disagree with Ewan just a little and say "Its unlikely to matter much"
I dont think I have ever used parallels above my ref. I have used 123 blocks above my ref.
Now I can work in either metric or imp but normally will work in metric. As the imp blocks I have seen are always much cheaper than metric ones and I'd rather add 25.4mm to something to use an imp block in metric than add 0.984251968503937"(give or take ) to use a metric block in imp, I'd go with the imp blocks.

Stuart

p.s. Not only are the blocks more than twice the price...... so it the postage
1 Matched Pair Ultra Precision 1 2 3 Blocks 23 Holes 0001" Machinist 123 JIG | eBay
1 Matched Pair Ultra Precision 25 50 75 MM Blocks 23 Holes 0001" Machinist | eBay
The metric blocks have 3/8UNC threads

Hi Simon,
Doesn't really matter about imperial or metric, but I would rather metric blocks that way if you do use them for a job that requires the 25/50/70mm you can use the blocks to accurately get it.
99% of the time though it would not matter.

I would like a few sets of the 100mm and 150mm blocks, but postage gets expensive for them.

Dave