123 1-2-3 blocks - Ask before you order!

jjtgrinder

jjtgrinder

JJTGRINDER
H-M Supporter Gold Member
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Dec 6, 2011
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I saw a comment from another member that said the 1-2-3 blocks that are sold by Micro-Mark can be bolted together in various configurations. I ordered a set from them, they are no different from other Chinese sets. The holes are too small to pass a 3/8 bolt through.
 
Grinder

I dont know why they build them that way. I have several set of blocks, and they are the same as yours. I have one set that I opened the holes to pass the bolt through. Them blocks were very hard.
All the blocks I have are imports, maybe thats the problem?
 
Is it possible they are metric threads?

Cheers,
Chazz
 
The blocks I have are 3/8 16 threads, the through holes wont let you pass the bolt through.
They should be a 3/8 through hole. (':shrugs:')

The set I bored the holes out to 3/8ths were harder than the gates of hell, or harder than the back of Super mans head. (':biggrin:')
 
I have 2 sets of Brown & Sharpe the through wholes on one set is 3/8s and the other are? 3/8 bolt won't go through them.

Paul
 
jjtgrinder said:
I saw a comment from another member that said the 1-2-3 blocks that are sold by Micro-Mark can be bolted together in various configurations. I ordered a set from them, they are no different from other Chinese sets. The holes are too small to pass a 3/8 bolt through.
Click to expand...

I think I was the one that mentioned the blocks from Micro-Mark. I called before I ordered and they checked both sets of blocks they had on hand and the cheaper set were clearance drilled. I ordered four sets and the were all clearance drilled.

I am assuming you ordered the cheaper set the same as I did and can only suggest that they have changed suppliers and now provide the same mystery blocks that everyone else has.

Arvid
 
As a matter of interest, what size are the through holes?
Is it close to 3/8 clearance and somewhere along the way the hardening process is playing with the diameter.
Could you fit a 3/8 x 16 stud to the tapped hole and have a reduced size, (5/16?) on the other end to pass through the "clearance" hole?
I doubt it is a "metric thing" as 10 mm is larger than 3/8 anyway.

Cheers Phil
 
12bolts said:
As a matter of interest, what size are the through holes?
Is it close to 3/8 clearance and somewhere along the way the hardening process is playing with the diameter.
Could you fit a 3/8 x 16 stud to the tapped hole and have a reduced size, (5/16?) on the other end to pass through the "clearance" hole?
I doubt it is a "metric thing" as 10 mm is larger than 3/8 anyway.

Cheers Phil
Click to expand...

The two terms that I have see used is "clearance drilled" where the hole is large enough to pass a 3/8 bolt thru and "tap drilled" where the hole is the correct size for tapping a 3/8 x 16 thread.

All of the blocks I have EXCEPT for the Micro-Mark sets look like all of the holes are tap drilled and then five of the holes are actually tapped. The Micro-Mark sets look like five of the holes were tap drilled and tapped and all the rest were clearance drilled.

Yes, a 5/16 bolt will fit thru the tap drilled holes and your suggestion for turning down and threading one end of a 3/8 stud to 5/16 sounds like a great idea.

Another option I have seen discussed is to turn down a 3/8 bolt so it will fit thru the tap drilled holes. Yes, you would need to turn down both the outside diameter of the threaded portion and the body of the bolt but you do not need to remove all of the threads and speculaiton is that the threads that are left would be adequate for holding the blocks together. Just don't lose track of the bolts and accidentially use them to attach the front spindle to your car :).

I have also seen an article in one of the magazines where a fellow built a 'kit' of 1, 2 and 3 inch long 5/16 rods that were milled and tapped for 5/16 bolts and then the rods were inserted as needed into the 'columns' in the block to allow 5/16 bolts to be used to hold them together. It looked like a great beginners or rainy day project.

Certainly a number of solutions but I would certainly pay a little extra for blocks that were clearance drilled for 3/8 in the first place.
 
Just checked mine
Tapped holes are 3/8 16, no question on that!
The non tapped holes measure 0.355

So, in the case of mine, they were not drilled 5/16 and just not tapped.
Those non tapped holes might be for a metric size though.

Any time I have used the blocks as a fixture, I have used 5/16 bolts in the through holes, but she,s a pretty sloppy fit. Usually if I need them nailed down on the mill table, with T-nuts under them.

Sure would be nice if they were tapped 3/8, with 3/8 through holes. They would be alot more usefull.
If the end user wanted to turn down bolts 0.020 to fit through the holes, I guess its doable. But whats the chances of your turned down bolts being proper length? Then the bolts would be a loose fit regardless.
 
Gentlemen
Is there a reason that you don't make your own? Ditto for angle plates, sine bars, parallels, vises, etc. After all you are hobby machinists and make things from metal for your own use.

Gene
 
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