Parallels

There seems to be two types, the less expensive wavy ones like These or the more expensive straight ones like These or These

Is there avantage to the more expensive ones?

The wavy ones work well under thin work because they can be compressed somewhat. A pair of straight ones is what I use under work that is wide enough to accommodate a pair of straight parallels.

Thor

So the best of both worlds

I favour the usual straight ones.

I've got quite a pile (in excess of 300!)of slip gauges that have failed calibration for precision use.

Jim

I tend to use the ones like the second link 99% of the time, I only get the wavy ones out when the work is thinner than one of the solid ones. It is also easier to keep track of where the solid ones are under the work so you don't drill or plunge cut into them

Always use the rigid ones.

Not confident that a wavy one, capable of being compressed would maintain parallelism

Howard

The waves are at right angles to the surfaces used, they cannot stretch.

I have a Chinese mill and a Chinese vice. None of them is really accurate. So I made parallels on the mill from mild steel. Marked a corner so that I can place them the same way they are made.

Now I have a reasonably accurate result, most of the time within 0.02 mm. When I damage a parallel, I just mill the top flat again.
Noway I can achieve the same or better accuracy with accurately ground parallels.

In time, when I have a new milling machine, I (maybe) will adjust the vices using a pair of 123 block.

What ever you go for check they are what they say they are.
The ones I have in a red plastic case claiming:
Parallelism Accuracy: 0.0002"
Size Tolerance: ±0.0002"
one out the ten pairs was out by 0.004" along the length and the ground edge was at angle, wondered why it kept falling over when placed in the vise!
Like Huub I've started making my own out flat bar

Thanks guys

In my orgional post i linked to two sets that look very similar, one from Warco and the other from Arc. To me they look the same, am i missing something?

Edit, the set from Arc was the wrong link, this is the set i was looking at Here

Edited By petro1head on 15/05/2023 06:50:31

Not parallels but a gander at emmas spare room machineshop vid on youtube - of her reviewing a cheap set of angle plates might be enlightening for anyone considering buying cheap. Easy to find as it is, I think, the only review she did - she was just too honest and showed what rubbish the kit really was. Here is a LINK .

I use the Arc set, almost universally - but they can be awkward if drilling to closer than 5mm from the edge.

If I want any more, I may purchase a wavy set and make/finish any, like those in the warco link, on the surface grinder. Mine would likely be case-hardened mild steel, rather than through-hardened - unless I’ve got some suitable tool steel close to the size(s) needed.

User selection is always a relevant factor. The warco ones are a bit naff if your vise is a deep one, little point in paying for 150mm if every thing will be satisfactory with 100mm parallels, wavy ones are softer (spring steel) but may be relevant for drilling close to an edge.

For raising items from the mill table, I also use old bearing races and other precision parts recovered from used items. ‘Spacers’ made on the milling machine can be perfectly adequate for most operations, I might guess?

ARC ones are all 150mm x 5 x incremnt.

Warco are smaller at 100mm long and only go upto 24mm tall which woyld leave you a bit short if wanting to hold shallow work in say a 100mm vice as the jaws on them are typically 38mm high.

I edited my post to include the correct set, so comparing Arc 100mm to Warco 100mm

My vice jaws are 100mm long by 32mm high. So in fact neither set would suit as the 20 pair set only goes to 24mm and the 14 pair set goes to 50mm which seems  waste

This is the vice I use, the 100mm one

Edited By petro1head on 15/05/2023 07:17:46

Wouldn't surprise me if they were identical from the same factory, or from different continents. Parallels aren't difficult to make and they're not protected by a patent. Anyone can produce them. Though I own a set for convenience, I've milled a few of my own to get just the right size.

My bought set were made on a grinding machine. These are very common in industry worldwide, and accurate when adjusted correctly. However:

• An out of adjustment machine could churn out a faulty batch before the operator re-sets it
• A business trying to earn a crust from worn-out equipment on it's last legs might be knocking them out cheap or as fakes
• Manufacturing rejects turn up in the market as 'bargains'
• Unless extra is paid for certificated accuracy, it's unlikely that parallels will be inspected individually.

For this class of item, it's cheaper for everyone to let the customer to detect errors and let the retailer refund or replace. Refund/replace is always a nuisance, extra difficult if the seller is abroad, and the system breaks if the customer buys from a dodgy supplier.

It also winds customers up, particularly those convinced inexpensive tools should be just as good as their top-of-the-range equivalents. In the real world, the cost difference can't be ignored: there's a reason top-of-the-range tools are expensive. It's the cost of ensuring they really do meet a specification, so a 'time is money' customer doesn't waste time sorting out even a percentage of iffy tools.

My set happened to come from Warco, and all the parallels are correct. I didn't expect Warco to guarantee the set would be acceptable on delivery, but I bought confident that they would replace or refund if there was a problem. And in practice, buying from Warco, only one purchase has ever gone wrong, and they replaced the item. Arc Euro have never fouled up, I think because Ketan knows his stuff and puts extra care into purchasing. I don't expect perfection from ArcEuro either, but in the event a dud arrived I'm sure they would refund or replace. Tracy Tools haven't dropped the ball yet either. I've bought successfully from several other UK vendors, but not often enough to find out how well they perform when a purchase goes wrong!

My experience at Shows and buying cheap off the internet has been less happy. Internet 'bargains' I see as a gamble, and I usually win. No tears if the 'bargain' turns out to be anything but, I knew it was a risk.

All my worst junk came from shows. At these, the distance buying regulations don't apply because purchasers can check the actual item. For example, I bought a box of cheap carbide inserts and found later they were rejects. Not a complete waste of money because they all had at least one correct edge, but I kicked myself! My fault - the box had a clear plastic lid, and all I had to do was look.

There's no law that show bought stuff is always rubbish, my best bargain purchases all came from shows. And this is true of all purchases, the buyer always has to apply due diligence and manage expectations.

Dave

Edited By SillyOldDuffer on 15/05/2023 08:55:17

A lot will depend on where you use your parallels, I don't just use mine in the vice, they get used to support work in other ways such as on the table or with angle plates so the larger range of heights upto 50mm is useful to me.

Also consider if 150mm is better than 100mm, I quite often machine work that is longer than my 100mm vice jaws and having that bit of extra parallel projecting out the side offers some support to the overhanging work and reduces the chances of work deflection or chatter. I will often use a couple of datum pins in the bottom of c casting and rest these on a parallel to set the casting horizontal if I want to machine the side so again if pins are further apart then the longer parallels work for me.

Thanks, excellent answer.

Is it ok to stack them. Ie a 20mm high one with a 5mm high one

I use pairs of HSS tool blanks as parallels. Providing you use them the same way up using the angled ends as a guide, I cannot measure any difference between the various pairs. I have a selection, ranging from 5mm up to 10mm.

I don't tend to make stuff for NASA , so these are good enough for me.

Everytime I want to buy parralels, something else crops up, but in the mean time I use 16mm & 12mm HSS toolbits I got.

Sometimes the only important feature of a parallel is that it is parallel and it has a matched pair. Other times the dimension is important as well, perhaps setting up work on a surface table for marking out will require accurate parallelism and dimension.

Mike