1-2-3 blocks

In all the years Ive been a machinist I've never had 1-2-3 blocks ,so thought I would get a set or two , I could use them for setup and maybe
a quick and dirty angle block ,so I purchased a couple sets of these 123 blocks from Shars Ebay site. They're cheap enough so if they are crap , I havent blow a whole lot of dough on them .
http://www.shars.com/products/view/2275/Ultra_Precision_123_Block
My impression was that the bolts in the kit were for fixing the blocks together , but the untapped holes in these blocks are not clearance holes for the bolts ,I reckon they are drilled tapping size for the 3/8"
On thier Ebay page they state that the holes are through holes http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item30534540192&ssPageName=STRK:MEWNX:IT
Here's me thinking that the holes would be clearance for the bolts supplied in the kit. I guess they are correct in one sense the holes do go through the block , but the bolts won't go through the holes.
I have a pair of 2-4-6 blocks with 5/8 " threaded holes ( chinese manufacture) and the untapped holes will allow a 5/8" bolt to pass through.
I sent a query to Shars and they say they have been selling them for years and no one has ever brought this up with them ,and that they are made to American standards .
If the blocks are not meant to be bolted together , why do they supply bolts in the kits.?
Of course modifying them and drilling the holes out to clearance will very difficult as they are hardened and a cobalt drill won't even look at them.
Can anyone enlighten me on this , I thought I read some where that the original Starrett blocks were able to be bolted together .
Thanks in advance for any information .
--
Kevin (Bluey)
"I'm not young enough to know everything."
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Maybe for that price they drill all the holes with the same drill, then tap some of them. I use the next smaller size of threaded rod to fasten them together and to angle plates. I should make a couple of tee slot nuts tapped for threaded rod for the mill; I did for the rotary table.
jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 4/16/2011 10:11 PM, Jim Wilkins wrote:

I'm thinking about getting a 10mm Artu brand drill and trying to open the untapped holes out so the 3/8 " bolt or threaded rod will pass through ,the Artu drills are supposed to be able to drill hardened steel.
--
Kevin (Bluey)
"I'm not young enough to know everything."
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I've got 5 sets of 123 blocks. One set has through holes that will pass 3/8 bolts, the rest just by eyeball, are all drilled with the tap drill. Guess it depends.
Good luck with drilling them, hope that works out.
Jon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 4/16/2011 10:54 AM, Jon Anderson wrote:

I have read in vintage machining books that the purpose of the untapped holes was to allow a threaded rod to pass though, but nearly all blocks made now (at any price) don't seem to bother with that extra step. :\
Drilling out the holes in a $10 pair of Chinese blocks requires a $40 tungsten drill bit.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have a nice pair of Finn brand blocks that came with SHCS and they can be assembled in many ways. Handy.....but not cheap.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 4/16/2011 9:47 AM, DougC wrote:

I just step down to a bolt that will fit through the hole. But that leaves unanswered, why Kevin's set came with bolts that won't pass through the untapped holes. I've never bought a set that came with bolts, so I do find the question interesting.
Jon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I bet they are being economical with the truth here. Nor is this up to Starrett standards for sure.

I had this exact experience with some blocks sold by MSC. Probably from the same noodle factory. I did complain to MSC, but got nowhere. What I wanted was a clear description in the catalog and website.

One can open the holes with ordinary masonry bits on a drill press. Very noisy, often ruins the cheap masonry bit, but it does work. I use copious flood cooling. And firm clamps - nothing can be allowed to move.

It would certainly make sense to do it that way. But maybe not for $10 per pair of 123 blocks. Again, what I would ask for is a clear and understandable description. So we know who is doing it right.
Joe Gwinn
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.