# 123 Block question



## Suwannee Tim (Aug 30, 2020)

Most shops have at least one set of 123 blocks, I bought two pair not long ago, seemingly they are standard equipment.  The pairs I bought have tapped holes and through holes and were shipped with socket head cap screws fitting the threads in the blocks.  The through holes in the blocks are not clearance holes for the SHCS though as I would expect them to be, they are too small to accept the SHCS.  My question, what is the purpose of these tapped holes and through holes if not to screw the 123 blocks together to make a 223 block or a 143 block?  It seems to me the unthreaded holes should be clearance holes with counterbores for the SHCS.  Does anyone actually use these threaded and through holes and for what?  Other than standing a workpiece off machine table what are 123 blocks good for?


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## machPete99 (Aug 30, 2020)

Chinese have been making these "wrong" for decades. Search for Suburban Tool for their story on the subject, or go here:


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## petertha (Aug 30, 2020)

This is a well know <cough> design flaw. You should be able to find lots of background discussion searching the forum. 
Dang, machPete99 beat me to it with Don Bailey vid. Here is another.


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## matthewsx (Aug 30, 2020)

Yes, this has been discussed here but I can't find the thread right now.

Essentially what happened is someone way back made some of these blocks and messed up. The part was then sent to China where that mistake has been reproduced a million times.

If you want ones that are made right you can get them here.



			PRECISION TRI-BLOCKS / 1-2-3 BLOCKS  by Suburban Tool, Inc.
		


Don't bother trying to bore yours out, they are hardened and will just destroy your drill bits.


John


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## Suwannee Tim (Aug 30, 2020)

Thank you for edjumacting me on the subject.


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## Suwannee Tim (Aug 30, 2020)

Video posted by petertha is informative, thank you for that.  A question, at 8:30 Renzetti knocks on the SHCS with a knocker, what is he doing there?  I had a question, I have seen machinists bang on a workpiece with a dead blow hammer seemingly to seat workpiece onto parallels into vise.  It always seemed unnecessary to me, I now see it is indeed unnecessary.


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## higgite (Aug 30, 2020)

Suwannee Tim said:


> Video posted by petertha is informative, thank you for that.  A question, at 8:30 Renzetti knocks on the SHCS with a knocker, what is he doing there?.....


He's knocking it as close to zero runout as he can by eyeball. When he first snugs up the nut, notice how the screw head wobbles when he starts the lathe, then watch how it doesn't wobble when he restarts the lathe after knocking it and tightening the nut.

Tom


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## petertha (Aug 30, 2020)

matthewsx said:


> Essentially what happened is someone way back made some of these blocks and messed up. The part was then sent to China where that mistake has been reproduced a million times.



I would love to know what really went down. I've heard a few theories:
1) sent them (or they decided to make) legitimate blocks to reproduce. But they failed to see the significance of an alternating tap hole, clearance holes, applied their own 'cost reduction' measure by drilling all tap holes but threading alternating holes. Which is the current model in all its useless glory.
2) (for conspiracy buffs) sent them a known dud which was faithfully reproduced. Hmm... not sure there. Engineer humor? Marketing booby trap? They seem to be doing a brisk business selling duds to all us hobbyist newbs so its not like they got caught with their pants down holding 5 years of 'now what' inventory LOL.

The real question is, particularly because its so painfully obvious the blocks could be so much more USEFUL with just a small change. Why not just swap out the bit & drill the fricken holes correctly? I mean it has to be cnc, they do a decent job of heat treating, grinding, holding tolerance, reasonable price... But once hardened that pretty much limits the remedial options. I said this before on another related post. Someone should file a bait patent application for the RR blocks. Then I bet we'd see them pop up in tooling catalogs within a few months LOL.


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## petertha (Aug 30, 2020)

Found one of the prior posts & contains some remediation ideas








						Leggos for Machinists
					

Well, not quite.  About a year ago, I purchased five pairs of 1-2-3 blocks to go with the pair I already had.  My intent was to use them for machining setups, etc.  As mny of us already knew, although the Asian blocks have 3/8"-16 threaded holes on the 2 x 3 face, all the through holes are bored...




					www.hobby-machinist.com


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## gonzo (Aug 30, 2020)

_In my ignorance I can't conceive of a use for screwed together blocks. I think I will be happy with my nine dollar ones._


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## matthewsx (Aug 30, 2020)

Right angle fixture?


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## coffmajt (Aug 30, 2020)

If you use carbide drill bits you can drill the hardened 123 blocks without problems.  I mean real carbide bits, not the carbide tipped ones == Jack


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## Flyinfool (Aug 30, 2020)

Are 123 blocks typically hardened thru or case hardened?

I was thinking of making some Renzetti style blocks but I can only case harden, sort of.


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## Masterjuggler (Aug 30, 2020)

To clarify terms, the way I understand it is case hardening is specifically hardening a low carbon steel in the presence of carbon to absorb into the surface of the steel. I'm not sure if these blocks are made that way, but even if they are tool steel and fully quenched, the thicker the piece the softer the core will be.


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## petertha (Aug 31, 2020)

coffmajt said:


> If you use carbide drill bits you can drill the hardened 123 blocks without problems.  I mean real carbide bits, not the carbide tipped ones == Jack



I've always been tempted, but never brave enough to lay out the coin. I noticed some carbide drills don't list their hardness numbers, just recommended materials like tougher alloys which makes me wonder if carbides themselves vary?  





						M.A. FORD,5/16 HI-TUFF CARBIDE DRILL MA FORD,5-100-25601,KBC Tools & Machinery
					

M.A. FORD,5/16 HI-TUFF CARBIDE DRILL MA FORD,5-100-25601,KBC Tools & Machinery




					www.kbctools.ca
				




This one makes specific reference & seems well in the range although a different configuration than a regular twist/jobber. https://www.kbctools.ca/itemdetail/5-100-20541

I wonder how hard a typical Asian 123 block is? This one says 50-60 RC & maybe of bit better quality?








						FOWLER 52-439-032-0 1-2-3 Block Set with Bolts, 23 Hole Setup Block
					

Supplied in molded caseApplicationsIdeal for precision layout and set-up.FeaturesEach block precision ground on all 6 surfaces.Case hardened to HRc 50 - 60.Surface finish from 6 to 16 micro inches.Squareness on all sides to within .0001".(23) Holes: (5) 3/8"-16 tapped; (18) untapped thru...




					www.travers.com


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## matthewsx (Aug 31, 2020)

The cheap import ones are plenty useful as they are. If I already had the right size carbide drills (more than one) I might try drilling them out. Otherwise I would be tempted to buy one good set of US made ones if I had the need to bolt them together.

John


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## Masterjuggler (Aug 31, 2020)

If you were REALLY on a budget and time was no object, and have a lathe and a toolpost grinder (aka clamped dremel), you could stick the block in a 4-jaw and individually grind out each hole...... Ya know, if you hated yourself.


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## dpb (Aug 31, 2020)

The Suburban prices are absurd.


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## yendor (Aug 31, 2020)

Just Drill out the holes you need for your current setup. 
Over time as you use the blocks for different setups you will come down to just the last 3 holes and well - just knock it out.


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## Diecutter (Aug 31, 2020)

Thanks to the Suburban Tool U-Tube video above, I was able to find a used set of  three counter-bored 123 blocks on Ebay for $35.  No one had bid on them, probably because of the different sized holes in the photos. The description did not even mention this feature. Go figure.


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## T Bredehoft (Aug 31, 2020)

Is it so hard to turn down Allen head cap screws?


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## Masterjuggler (Aug 31, 2020)

T Bredehoft said:


> Is it so hard to turn down Allen head cap screws?


For what reason? If the shaft is turned down to fit through the holes, they'll no longer thread into the next block.


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## pontiac428 (Aug 31, 2020)

Suwannee Tim said:


> Video posted by petertha is informative, thank you for that.  A question, at 8:30 Renzetti knocks on the SHCS with a knocker, what is he doing there?  I had a question, I have seen machinists bang on a workpiece with a dead blow hammer seemingly to seat workpiece onto parallels into vise.  It always seemed unnecessary to me, I now see it is indeed unnecessary.


If I learned anything in my short time in CNC production, it was to always always wipe your vise jaws and seat your parts as you tighten them.  One chip can cost you .005" misalignment, failing to seat with a dead blow or leaded hammer will cost twice that.  After developing an "eye" and a "feel" for everything, the value of seating parts becomes obvious.  Even more obvious when you mic every single part, shift after shift.


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## T Bredehoft (Aug 31, 2020)

Masterjuggler said:


> they'll no longer thread into the next block.



My error, the ones I was familiar with decades ago were OK except the counter bore for the screw head was too small. Sounds like carbide drill time.


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