Easy as 1-2-3?

hman

hman

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I would dearly love to find a set of 1-2-3 blocks that allows them to be bolted together. Rick Sparber's great writeup, http://rick.sparber.org/123.pdf illustrates an old SPI set that definitely has this capability. Not only are the clearance holes large enough to take the bolts that fit the threaded holes, but there are also some clearance holes for the heads of the socket-head bolts.

I guess times have changed, and at least the Chinese have decided to "cheap out" once again. Nowadays, all I can seem to find are 1-2-3 blocks that are have 5/16" thru holes and holes threaded for 3/8-16. I guess their manufacturing philosophy is "Drill 'em all the same, tap a few, and get it out the door.":nuts: Unfortunately, you can't run a 3/8" bolt through a 5/6" hole!!!

I even tried emailing Little Machine Shop. Chris replied with a suggestion to fabricate some adapter nuts, 3/8-16 outside thread and 1/4" internal thread. Yes, it'll work ... but it seems rather kludgy.

Does anybody know of a source of 1-2-3 blocks whose clearance holes will take bolts the size of their threaded holes?

Alternatively, has anybody tried boring out a (hardened!) 1-2-3 block, say with a carbide end mill?

Thanks!
 
Have you looked at Enco?
 
Go to ebay.com and search "1-2-3 blocks" There will be a few hundred choices with a mix of new and used and various prices.
 
Not a new concern. Take a look at both of these threads, the first suggesting at least one vendor has a clue and the second suggesting that "the right thing" was no longer available.

http://www.hobby-machinist.com/show...s-they-should-be?p=41397&viewfull=1#post41397

http://www.hobby-machinist.com/show...efore-you-order!?p=53437&viewfull=1#post53437

The incorrect version seem to be so common that ... if I recall correctly ... there was an article in "Home Shop Machinist" several years ago with a reasonable solution to the problem. It is a copyrighted article so I can not copy and share it but I think it is legal to describe the solution ... as best I remember it.

The key was to forget about the tapped holes in the block. In very general terms ...

Find a drill rod that would just fit thru the untapped holes. Maybe a 5/16 rod? [the ? means I am not sure of the size so measure before you buy :))] Cut the drill rod so you had a bunch of 1, 2 and 3 inch pieces. Now push the appropriate length drill rod into the block from the appropriate side ... i.e. the 1 inch rod into the block so the ends of the rod are flush with the block, the 2 inch ... you get the picture.

Now look into the holes in the block that are perpendicular to the rod. You should be able to see where you would drill and tap a hole perpendicular to long axix of the rod. Yes, the drilling and tapping will be the very challenging "perpendicular to the length of the rod" type.

Now remove the rod and drill and tap the hole. Obviously you drill and tap the hole a reasonable size ... not so large that it compromises the strength of the rod and not so small that the screws you will eventually be using will wimp out when holding thing together. Maybe a 1/4 - 20?

In use you put the rod(s) into what ever holes you need to solve you fixture problem ... i.e. the threaded hole in the rod allows any hole in the block to appear to be "threaded" ... just using a smaller bolt than the 3/8 - 16 that is normally there ... and then use an appropriate length screw ... which by definition will fit thru any of the holes in any of the blocks ... to hold the blocks together.

If I recall correctly the article also milled a flat spot on one side of the drill rod at the location of the drilled and tapped hole. This would allow the head of the screw to that a flat spot to land on rather than being on a tangent of the drill rod diameter.

Not a great solution because the size of the screws that can be used are certainly smaller than what you would use if the block holes were actually the correct size, but it looked like a very useful 'beginners' project for the lathe and mill.

Arvid
 
Thanks to all of you for your replies.

Jim - Hadn't looked at Enco, and was surprised at the wide range of items they had (once I figured out what to look for!) None of the descriptions state the size of the thru holes, though, so I've sent them an email.

Cadillac STS - Ebay was one of the first places I looked. Unfortunately, none of the listings seem to state the size of the thru holes they have, so I'd have to email every one of them to find out. Looking at many of the photos, it's pretty apparent that the thru holes are smaller than the tapped holes :(

arvidj - Thanks for the links. At least one of them seems to have nice things to say about Micro Mark. Their description does mention bolting the blocks together, though it doesn't say what size the thru holes are. I've sent them an email. PS - guess I'm not the first one to bring this up. Bummer that the majority of current offerings is so messed up.

I'll keep looking, and let y'all know if I find any good news.
 
John,
I don't know if this is even in the ballpark. Can you take a bolt that fits the thread and is long enough to pass through one and most of the way through the second and then turn part of the bolt to the minor diameter so that after it pass through one it will spin free?
Dave
 
I solved that problem a couple of years ago. I made my own 123 blocks.
 
I just looked at my old B&S 123 blocks. They have 3/8 holes drilled through, with the exception of the 5 center holes that are tapped 3/8-16.

The 5 tapped holes are circled

IMG_0394.jpg

IMG_0394.jpg
 
Just browsing eBay. I see what you mean, most are not made to "Sink the bolt head." in the block.

Here is a set that might work. Search eBay for TTC PR-1232 Universal 1-2-3 Block Set

I couldn't get the link to post here but that search will bring you to blocks that I think are what you are looking for.


Not the only one on ebay just one that came up but an example of what the OP was looking for
 
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I bought some files from Micro Mark. They were cheap junk. Somehow,the end of 1 needle file was bent up into a small fish hook shape!! They were just miserable. I do not advise buying precision tooling from them. They are strictly hobby level. Wortse actually,if their stuff just can't be used.
 
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