How to drill 1-2-3 blocks

[Janger]

Ok I bought four of these basic 123 blocks from accusize. All the holes were drilled to tap ( they measure about .355”) so they are too small to pass a .375 ready rod or bolt through. I thought maybe I can drill them out. They are hardened though. Regular drill bit no not at all. I tried a used carbide bit I have. Chowdered it after about half way through one hole. So …

I had one thought to anneal it - maybe in a aluminium foil bag? Then drill and then reharden them? Or is this just going to create loads of oxides and ruin the surface so it’s no longer accurate?

Looks like the server won’t upload larger files again I’ll see what we can do about that.

 

[Dabbler]

So, ah, no. From ACT you can buy drills designed to drill up to Rc65, which should be more than sufficient.

Re-annealing will just ruin your surface finish, and then they need to be reground.

Or, on the other hand if all you need is clearance, why not grind out the holes with a barrel stone? (unless you need a *lot* of clearance?

 

[little ol' e]

@Janger ,

Drilling with carbide will take some time if you blast it with air but it would be expensive. I would plunge the holes out with a carbide endmill if you can. If you use coolant, that will be your enemy and work against you.

I agree with @Dabbler on annealing the process.

 

[Janger]

Well I ordered a set of bolt and dowel pins at dabbler’s suggestion. Let’s see how they work out. I wasn’t looking forward to all that drilling.

123 Block Attachment Hardware Kit

123 Blocks are a common accessory found in nearly every machine shop machine shop and are useful for numerous work support, set up and inspection tasks. 123 Blocks are even becoming more coming on woodworking and DIY shops. What makes 123 block so useful is they’re made from hardened steel and...

taytools.com

 

[PeterT]

Haaaaay.... that looks oddly familiar! LOL

123 Block Attachment Hardware Kit

123 Blocks are a common accessory found in nearly every machine shop machine shop and are useful for numerous work support, set up and inspection tasks. 123 Blocks are even becoming more coming on woodworking and DIY shops. What makes 123 block so useful is they’re made from hardened steel and...

taytools.com

 

[LenVW]

I ran into the same problem when I purchsed some 1-2-3 blocks, last year.
A couple of 5/16” Rod pcs, 1/4“-20 machine screws and nuts was all that was needed to tie the blocks square. I did machine flats on the rods before drilling and tapping.
If you try to heat them up for boring out the holes you will ruin the finish and cause distortion.

 

[Mcgyver]

I'd send them back or use 5/16 UNF ready rod. If you anneal you'd have to harden temper and regrind, not worth it.

You guys must be more creative than I; I've a bunch of them and use them often enough but I don't think I've every bolted two together

 

[Matt-Aburg]

0.355 x 25.4 = 9.017 mm (9mm screw...) I would not mess with the HT, unless you have a surface grinder and accept non standard blocks. How about circle milling with 4 flute carbide Emill?

 

[PeterT]

You guys must be more creative than I; I've a bunch of them and use them often enough but I don't think I've every bolted two together

I must admit, for me it was more for morbid curiosity to see if I convert my offshore bastards after seeing the Renzetti structures. I've never used my contraption since. I found the inserts a bit fiddly to orientate & not exactly secure due to round T-nuts in round holes. If a you don't have a requirement where all the hardware must be internal, then undersized fastener shanks & protruding heads is fine. An angle block with threaded hole matrix might be more useful for holding in the crotch or different machining orientations. But seems to me the bigger ones have even bigger threaded holes & spacing? I like tooling plates, lots & lots of smaller holes at closer spacing, but that's probably related to my fiddly parts. I've thought about making my own but Santa did not bring me a surface grinder.

 

[Susquatch]

Regular drill bit no not at all. I tried a used carbide bit I have. Chowdered it after about half way through one hole. So …

Diamond? Doesn't need to be a great hole. Ive never used a diamond drill except on glass. It was just what popped into my head.

If it was me, I'd just use smaller fasteners. I can't think of a single application where the strength of the bigger fastener is required.

Heck, you could even make a few special buttons or sleeves or caps to center the smaller fasteners if you want.

 

[LenVW]

I'd send them back or use 5/16 UNF ready rod. If you anneal you'd have to harden temper and regrind, not worth it.

You guys must be more creative than I; I've a bunch of them and use them often enough but I don't think I've every bolted two together

 

[LenVW]

The Photo will not attach.

 

[PeterT]

If it was me, I'd just use smaller fasteners. I can't think of a single application where the strength of the bigger fastener is required.
Heck, you could even make a few special buttons or sleeves or caps to center the smaller fasteners if you want.

That's pretty much what everybody does in one variation or another. Its a workaround contest seeking a least pain remedy for the ridiculous oversight that the pilot hole for a specific thread size is smaller diameter than the required clearance hole. So given this predicament its A) increase the hole size B) adapt the existing thread with an insert C) bypass the thread with a nut on other side or some internal dowel T-nut like examples shown. Each mod has their pros & cons. And I was one of the many sheep who bought these without fully comprehending the issue. Because 'real' ones look similar - there's holes & there's threaded holes, assume the offshore manufactures just measured & copied. Apparently not. Don't get me wrong, they are good value for what they are. The block of steel would cost more at MSM never mind the machining, heat treating & grinding.

Sadly these types of blocks just keep coming. How much effort would it be to change out the drill on a CNC & drill the proper hole? We may never know. IMO if one rarely bolts them together to make fixture structures, just buy the solid blocks or ones with single center hole. Easier to clean swarf out & arguably last longer, less distortion.

 

[Susquatch]

The Photo will not attach.

The problem is being worked on. For now, try reducing the photo resolution.

 

[Matt-Aburg]

That's pretty much what everybody does in one variation or another. Its a workaround contest seeking a least pain remedy for the ridiculous oversight that the pilot hole for a specific thread size is smaller diameter than the required clearance hole. So given this predicament its A) increase the hole size B) adapt the existing thread with an insert C) bypass the thread with a nut on other side or some internal dowel T-nut like examples shown. Each mod has their pros & cons. And I was one of the many sheep who bought these without fully comprehending the issue. Because 'real' ones look similar - there's holes & there's threaded holes, assume the offshore manufactures just measured & copied. Apparently not. Don't get me wrong, they are good value for what they are. The block of steel would cost more at MSM never mind the machining, heat treating & grinding.

Sadly these types of blocks just keep coming. How much effort would it be to change out the drill on a CNC & drill the proper hole? We may never know. IMO if one rarely bolts them together to make fixture structures, just buy the solid blocks or ones with single center hole. Easier to clean swarf out & arguably last longer, less distortion.

This is not an oversight, in my opinion.

I have many Chinese tools that are graduated inch with metric threads. One good example is the boring head from KBC. Have you entertained the possibility that the critical surfaces are inch, while the non critical holes are metric. I already calculated that the hole is 9 mm. Would it not be easier to buy some metric screws to go in those holes. I mainly work in inch, but have metric and imperial allen keys. Sometimes you have to work in both units. In 32 years of this trade, I have never used the holes. I always through they were there for weight reduction.

 

[PeterT]

This is not an oversight, in my opinion.

I have many Chinese tools that are graduated inch with metric threads. One good example is the boring head from KBC. Have you entertained the possibility that the critical surfaces are inch, while the non critical holes are metric. I already calculated that the hole is 9 mm. Would it not be easier to buy some metric screws to go in those holes. I mainly work in inch, but have metric and imperial allen keys. Sometimes you have to work in both units. In 32 years of this trade, I have never used the holes. I always through they were there for weight reduction.

Maybe this sketch will help. The pseudo clones have an array of alternating threaded hole & through hole. But their through hole diameter is smaller than the shank dimeter of the thread. My guess is they drilled all the holes in the block with the same pilot drill size (example 5/16) then tapped the alternating holes (example 3/8-16). So how do you pass a 0.375" OD fastener through a 0.3125" hole in order to mate the blocks together? Yes you can put a smaller diameter fastener through the small pilot hole, but its not going engage the thread so what's the point. The other picture shows what I think are the original concept - the non threaded hole is a clearance hole size.

Yes I have seen similar offshore blocks based on metric too. Some are 123 (as in inch) with metric threads. Some are metric block dimensions with metric threads. Whether its imperial or metric isn't really this particular issue. The question is are they (thread + undersize) vs (thread + clearance).

 

[Susquatch]

This is not an oversight, in my opinion.

I have many Chinese tools that are graduated inch with metric threads. One good example is the boring head from KBC. Have you entertained the possibility that the critical surfaces are inch, while the non critical holes are metric. I already calculated that the hole is 9 mm. Would it not be easier to buy some metric screws to go in those holes. I mainly work in inch, but have metric and imperial allen keys. Sometimes you have to work in both units. In 32 years of this trade, I have never used the holes. I always through they were there for weight reduction.

I'm with @PeterT on this. I won't repeat what he has said. But like him, I believe they just plain screwed up. Even worse, we have the discount characters copying the cheap guys. We users lose. Someday soon, one the quality outfits is gunna get it wrong too cuz so many others are doing it wrong.

But I hear what you are saying. More and more often I am seeing mixed standard parts with both metric and imperial threads.

If I were not so guilty myself, I would have a right to complain. But I routinely mix standards - almost weekly. In fact, I just finished putting 1/2 hex heads on my metric fuel injector caps. Speaking of which, the whole darn tractor is mostly metric yet there are a few imperial things on it anyway. So I guess I'm in good company.

I wouldn't hesitate to use a metric fastener in my imperial 1-2-3 blocks if it worked better.

 

[Brian26]

Two things:
First - to drill out holes in hardened steel, I had some luck using Mad Dog drill bits - which look something like concrete bits, but a lot better, I think. Their brazing is rugged and their bits can drill through a lot of stuff other bits have no stomach for.

Second - one member suggested using diamond to cut steel. Not recommended. If you want to go in that direction, consider CBN instead.

 

[Janger]

Mad Dog drill bits? What are those? pics? links? prices?

 

[Brian26]

John - I just used a BING search for "Mad Dog Drill Bits" and got right to their web page. Pictures, prices and all. See if clicking on this link will help: https://baddogtools.com/multi-purpose-drill-bits