123 Blocks

Just seen this video, may be of help to others?

**LINK**

Hardware:

**LINK**

I have written to ask if there's a UNITED KINGDOM distributor and await a response.

MCB

As he said, it is not too hard to make your own.

Martin C

I think I recall a YouTube video on this subject.

Edited By Martin Connelly on 20/07/2022 10:07:22

Just put "dowel nuts" into google and you will find loads if you can't make your own. Also better choice of threads as the ones in the hardware kit are likley to be UNC.

Or contrary to what he says you don't need to spend a fortune to get blocks that will screw together, the ARC ones are correctly drilled and tapped

I gave mine away as I never used them. To be fair I have a selection of accurate parallels made by the father of a friend who was a toolmaker.

Andrew

I've never felt the need to make or acquire a set yet, nice to have but a good selection of accurate parallels are far more useful to me...

The company's web site (which doesn't work on my computer so I had to resort to my iPad) states that the threads of the dowel nuts are 5/16 8 - 32

Screwfix sell Dowel nuts very reasonably (their cost for 50 is around the same as B&Q's price for five!

The Screwfix nuts are 10mm in diameter so they probably would NOT fit in Arc's blocks.

.

M5 dowel nuts are 8mm diameter. Next time I'm in my favourite fastener supplier I'll see if they stock them.

Hi, I made these January 2017, I had never seen or heard of them before, but needed to fix a Stevenson's block to an imperial one, so just used a bit of BMS, used a transfer punch in the holes and drilled and tapped them for M5 threaded rod. Although I hadn't thought of making blank dowels to allow socket head set bolts to be used, I didn't need to for my application.

This is the use I did them for.

Regards Nick.

I have two pairs of 123 blocks in my stock which I have never had much use for largely beacuse 1) they are not obviously 1-2-3 by design (metric or imperial), 2) they only have holes drilled through from the front face and not from the edge and 3) None of the through holes are threaded. Do they have any potential use as 1-2-3 blocks?

Hi Greensands, the 1-2-3 is the ratio, they don't have to have an exact measurement of 1 2 & 3 in either metric or imperial and they don't have to have any holes in them at all, let alone be threaded, but it does help. I guess your blocks have a use for something all the same though.

Regards Nick.

Edited By Nicholas Farr on 20/07/2022 12:00:01

You missed the point that ARC's ones are correctly drilled clearance size and tapped not drilled tapping size so bolts screw in without the need for dowel nuts

Just buy dowel nuts to fit 8mm OD would be closest to the 5/16" American ones and fit the larger ARC blocks, 6mm OD for the smallest

I use mine as parallels and packing a lot as I only have sets of thin parallels. Also 20mm one gets used to set tool height on the CNC as I don't have gauge blocks either. The holes also make them easy to bolt to a faceplate or work when balancing things up for turning.

Edited By JasonB on 20/07/2022 12:14:12

I made my own adapters, both barrel nut type and threaded bush type. All have a variety of threads

Having 246, 123 and all of Arc's offerings, i needed to be able to join various size blocks.

Only a few hours work, but well worthwhile!

Jim

With respect, I have NOT missed the point,

I understand what has been written about ARC's blocks being tapped but it seems to me that the HEADS of the bolts used would get in the way and that a fixing below the surface of the blocks would be preferable.

.

I've not yet found that the heads of cap head screws have gotten in the way so far when I have joined mine together but can see using smaller screws could be handy in which case I'd just cross drill a couple of bits of rod to suit should the need arise

The expensive Starret etc ones all use 3/8" x 16 threads for screws with heads.

I bought 2 sets of the 124 blocks to sit the Tom Senior bed on while milling 1.5mm off the top, and got lucky with the sizes, in fact they are so perfectly matched that I have long since muddled up the pairs, better than 0.0001" the same in all axes. When I got out the older set of 123 blocks, they turned out to be also 124 size, but I have never measured them relative to the other 2 sets. I bought a pair of 246 blocks on ebay and it wasn't till much later when I was having trouble with setting something up that I realised they were parallograms. Sitting them back to back on the surface table, there was room for a 0.025" feeler gauge in the 4" side. Chris got them ground square in all axes.

Edited By old mart on 21/07/2022 20:11:56