1-2-3 blocks

[EdK]

Curiosity got the best of me so I went and checked the two sets of 1-2-3 blocks I have. The Phase II set has unthreaded holes that almost pass a 3/8" bolt through them but not quite. The no-name set has the minor diameter bolt dimension for the unthreaded holes. I think they are just surface hardened. Would a carbide drill bit work to drill these holes out?

Ed

[PixMan]

(02-01-2014, 07:01 PM)EdK Wrote: Curiosity got the best of me so I went and checked the two sets of 1-2-3 blocks I have. The Phase II set has unthreaded holes that almost pass a 3/8" bolt through them but not quite. The no-name set has the minor diameter bolt dimension for the unthreaded holes. I think they are just surface hardened. Would a carbide drill bit work to drill these holes out?

Ed

A carbide drill would work, though I'd advise against using hand fed quill motion to do it. Better to bring the drill close to the work with the quill, then use table (knee?) feed to drill the hole. This will prevent the drill from sucking itself in and breaking.

[EdK]

(02-01-2014, 07:30 PM)PixMan Wrote: A carbide drill would work, though I'd advise against using hand fed quill motion to do it. Better to bring the drill close to the work with the quill, then use table (knee?) feed to drill the hole. This will prevent the drill from sucking itself in and breaking.

Ken,

Yea, I was a little concerned about that also. Unfortunately I don't have a knee mill, yet. Maybe next spring though. It can wait.

Ed

[Mayhem]

(01-31-2014, 08:18 PM)hswaters Wrote: ...Who knows maybe some other guy as dumb as me will come along...

There is no such thing as a dumb question - only dumb answers.

One option would be to make some threaded studs with the 3/8-16 thread to screw into the block and a smaller thread on the other end to pass through the block. With a nut and washer, you could then bolt them together.

[arvidj]

(02-01-2014, 07:30 PM)PixMan Wrote:

(02-01-2014, 07:01 PM)EdK Wrote: Curiosity got the best of me so I went and checked the two sets of 1-2-3 blocks I have. The Phase II set has unthreaded holes that almost pass a 3/8" bolt through them but not quite. The no-name set has the minor diameter bolt dimension for the unthreaded holes. I think they are just surface hardened. Would a carbide drill bit work to drill these holes out?

Ed

A carbide drill would work, though I'd advise against using hand fed quill motion to do it. Better to bring the drill close to the work with the quill, then use table (knee?) feed to drill the hole. This will prevent the drill from sucking itself in and breaking.

Carbide may work.

I do know that the blocks do an excellent job of rendering a HSS bit useless with absolutely not damage to the block. I have two to prove it. Something along the lines of "an idiot will do the same thing over and over expecting the results to change".

I also know that a cobalt drill will get about a third of the way thru one hole before it gives up the ghost. Have two of those in an effort to verify that I am an idiot.

[arvidj]

(02-01-2014, 11:38 PM)Mayhem Wrote: ...

One option would be to make some threaded studs with the 3/8-16 thread to screw into the block and a smaller thread on the other end to pass through the block. With a nut and washer, you could then bolt them together.

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? 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

[aametalmaster]

When i was in HS Vocational Machine Trades in the '70s we made hundreds of them as a class project. But it taught layout, drilling tapping, case hardening and then the final grinding. Good beginners job making them even if not hard...Bob

[TomG]

(02-02-2014, 10:16 AM)aametalmaster Wrote: When i was in HS Vocational Machine Trades in the '70s we made hundreds of them as a class project. But it taught layout, drilling tapping, case hardening and then the final grinding. Good beginners job making them even if not hard...Bob

Most everyone made them back then because they were a project that taught a lot of techniques. I have no idea what happened to mine, they must have been left behind on some job.

Maybe I should get a grinder so I can make another set.

Tom