Universal 123-Block Hack ?

[graham-xrf]

It's such an ugly hack that I am almost ashamed to mention it - but here goes..

This is motivated by desiring a set of the famed Robin Renzetti 1-2-3 block, the merits of which can be found on YouTube, but of course, you cannot just buy them. You have to make your own. I do not have a surface grinder, nor heat treat kit.

Don Baily, owner of Suburban Tool Inc describes all that is wrong with the holes 1-2-3 blocks, but we all have noticed how a bolt that will fit the tapped threads won't go through the clear drilled holes - a very poor design choice. At least the Suburban Inc 23-hole blocks will allow being bolted together in this way.

The Moore 11-hole block is a beautiful thing that provides the functionality that Robin then takes to perfection with his Universal 1-2-3 blocks where every hole has a deep counterbore and a tapped threaded end, and are used with modified screws that can spin free if you take then right through the tapping, to be able to screw into the next block.

The hack?
Suppose one modified the common (non-functional) Chinese mass produced 1-2-3 blocks by putting the equivalent of a custom "helicoil" insert into one end of every other hole in a face, and drilling out the threads on one end of every already threaded hole. Then make a set of the special relieved screws by turning away the threads just under the screw heads. Essentially start with the common low cost block set, and modify them.

Given that 1-2-3 blocks are already as hard as bits of battle tanks, I don't know how possible all this is. Transforming a clear hole into a strong threaded hole might challenge the best of Loctite 638. Also - it's all just a mad speculation on my part. If I had the way to harden, then surface grind, I would aspire to making myself a set. I am driven to suggesting a tacky hack.

 

[Janderso]

You could always anneal them , do your machine work then do a diy reharden job.
I went to no hole or one hole 123 blocks.
They come in very handy and no holes to get the chips out of.

 

[graham-xrf]

You could always anneal them , do your machine work then do a diy reharden job.
I went to no hole or one hole 123 blocks.
They come in very handy and no holes to get the chips out of.

Yes - I had thought that A2 steel is reasonably forgiving in it's temperature range, and I can even contrive to know the temperature before quench. What we have is a block of A2 with 23 holes in it going all sorts of directions, and the faces ground to within a couple of tenths or so, and square. After annealing, and reworking, then harden, and quench, and re-heat to final temper, and quench, I am thinking it would no longer be "within a couple of tenths".

There would be the need for a final surface grind, and lots of care in measurement. It would also be a "slightly less than 1-2-3" if the numbers meant inches, but that matters less, They are not length standards.

I thought a carbide drill or milling cutter could be used to remove the unwanted threaded ends, and some sort of insert to provided a threaded hole onto the ends of the clear through holes. There is still the problem that the OD of the screws that would fit the present tappings don't go through the clear holes. Not wanting to make the holes even bigger, maybe the way is to make all the tapped holes a smaller thread.

 

[Janderso]

Yes - I had thought that A2 steel is reasonably forgiving in it's temperature range, and I can even contrive to know the temperature before quench. What we have is a block of A2 with 23 holes in it going all sorts of directions, and the faces ground to withing a couple of tenths or so, and square. After annealing, and reworking, then harden, and quench, and re-heat to final temper, and quench, I am thinking it would no longer be "within a couple of tenths".

There would be the need for a final surface grind, and lots of care in measurement. It would also be a "slightly less than 1-2-3" if the numbers meant inches, but that matters less, They are not length standards.

I thought a carbide drill or milling cutter could be used to remove the unwanted threaded ends, and some sort of insert to provided a threaded hole onto the ends of the clear through holes. There is still the problem that the OD of the screws that would fit the present tappings don't go through the clear holes. Not wanting to make the holes even bigger, maybe the way is to make all the tapped holes a smaller thread.

Can't argue with that.

 

[Masterjuggler]

How hard are these chinese blocks on the rockwell scale do you think? Not advertised, but actual. Wondering if you couldn't hard turn the holes with carbide or something, either with a boring head in a mill or in a 4-jaw chuck on a lathe.

 

[graham-xrf]

You could always anneal them , do your machine work then do a diy reharden job.
I went to no hole or one hole 123 blocks.
They come in very handy and no holes to get the chips out of.

Hmm.. a set of removable plastic thingys maybe.
I am absolutely all for keeping chips out of things. I see the extent some will go to with bellows, and aluminum shields, and leather fanfolds to keep the chips out of ways, especially mill scale and work-hardened.

See-thru polycarbonate shields around the business end of mills also. Mill chips can make it clear across the room!

 

[graham-xrf]

How hard are these chinese blocks on the rockwell scale do you think? Not advertised, but actual. Wondering if you couldn't hard turn the holes with carbide or something, either with a boring head in a mill or in a 4-jaw chuck on a lathe.

I guess in region of HR60 or so. You actually got me filing on my 123 block. It is supposed to take impact and not be glass-hard brittle.
It's harder than a warding file!

 

[NC Rick]

Carbide drill with the right geometry and speeds, feeds? Another thing i thought about was threaded bushing that are 3/8 16 outside and #10- 24 on the inside.

 

[Masterjuggler]

Considering the holes are actually useless right now and it wouldn't matter if the inside surface finish is beautiful, you might try hard turning it with a good carbide insert to see what happens. I'd bet cheap carbide would blow up no matter what.

Or you could use the concrete drill trick. I've seen people use decent carbide masonry bits to drill through hard digital calipers to mount them to things.

 

[graham-xrf]

Carbide drill with the right geometry and speeds, feeds? Another thing i thought about was threaded bushing that are 3/8 16 outside and #10- 24 on the inside.

Making the hole is surely possible with a carbide drill or milling cutter. We can make holes in glass and stone! Spinning an aluminum rod in 80 grit slurry would do it, and leave the aluminum rod more or less intact! Making the holes is a reasonably fraught exercise unless one takes care, but I think the holes is a reasonably straightforward task.

This assumes we settle for the ready-made slightly less than 3/8" holes, which is sensible. We don't want any more work than necessary!
The bushing you suggest is to be glued in with Loctite, and at the same time we adopt a smaller screw that will have an OD that will fit through the (apparently) 0.355" diameter holes. So far - so good.

Given that I am looking at 9mm holes (some 9.01mm, others up to 9.04mm), and thinking M6 bolts, and I don't actually know what is #10 screw, please forgive. Looking at tables for UNC, a 5/16 x 18 screw leaves only 0.03125 each side. A 1/4" x 20 leaves 0.0625 each side, which seems to me to be "enough".

So, is the recipe to get some 3/8 x 16 (maybe not very hard), cut to make a slug, ends faced to make a counterbore bottom when in place. Loctite 638 into the existing threads, and drill out and tap to (say 1/4" or M6)? That could work! Does one make the entire bushing first, or drill and tap when it is glued in place?