Universal 123-Block Hack ?

I think I'm going to keep putting off buying any after reading this thread LOL I don't need to drive myself crazy that badly
-M
Actually - they are just so very useful - especially for woodwork! Plonk two together in the right way, and you can rule 1, 2 , 3, 4, 5 and even 6. Stand it up against your circular saw blade, and adjust away. Guide a drill into a frame - dead square. I suppose there is no harm in clamping one into an angle-iron or box section weld. You don't get much else made to the precision, that works like a gauge block + handy parallel thingy that you can bolt down, all for about £20 for two of them!

It's the low price of the ground and hardened product that makes me think it is worth using them as a starting point to getting them the full features, and it's feeling like a project that is not way out in the realms of unreasonable ambition (for one like me) :)
 
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My approach to the Asian 1-2-3- block fault was to simply turn and thread some special studs with 3/8-16 threads on one end and 5/16-18 threads on the other. A few minutes of turning and single point threading per stud.
 
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My approach to the Asian 1-2-3- block fault was to simply turn and thread some special studs with 3/8-16 threads on one end aqnd 5/16-18 threads on the other. A few minutes of turning and single point threading per stud.
Thanks very much RJ. The thought had crossed my mind that it would be unlikely that I would be the only one on the case of 1-2-3 blocks in this context, and sure enough, you folk have wrung it out in a thread more than a year ago.

Your solution of using trick fasteners to work around the limitations of the Chinese blocks is absolutely the answer. I love it! Much better than attempting to modify hardened blocks, and it preserves their only good feature. You get there, even if not as elegantly as Robin's design. I will be going for your solution. :)
 
Making the hole is surely possible with a carbide drill or milling cutter. We can make holes in glass and stone! Spinning an aluminum rod in 80 grit slurry would do it, and leave the aluminum rod more or less intact! Making the holes is a reasonably fraught exercise unless one takes care, but I think the holes is a reasonably straightforward task.

This assumes we settle for the ready-made slightly less than 3/8" holes, which is sensible. We don't want any more work than necessary!
The bushing you suggest is to be glued in with Loctite, and at the same time we adopt a smaller screw that will have an OD that will fit through the (apparently) 0.355" diameter holes. So far - so good.

Given that I am looking at 9mm holes (some 9.01mm, others up to 9.04mm), and thinking M6 bolts, and I don't actually know what is #10 screw, please forgive. Looking at tables for UNC, a 5/16 x 18 screw leaves only 0.03125 each side. A 1/4" x 20 leaves 0.0625 each side, which seems to me to be "enough".

So, is the recipe to get some 3/8 x 16 (maybe not very hard), cut to make a slug, ends faced to make a counterbore bottom when in place. Loctite 638 into the existing threads, and drill out and tap to (say 1/4" or M6)? That could work! Does one make the entire bushing first, or drill and tap when it is glued in place?
an M6 would be a good deal stronger than a #10. I dislike our imperial thread sizes and use metric hardware where practical. Mixing the two bothers me. A lot. Some strange OCD thing im sure.
 
an M6 would be a good deal stronger than a #10. I dislike our imperial thread sizes and use metric hardware where practical. Mixing the two bothers me. A lot. Some strange OCD thing im sure.
Not OCD. I have lathe(s) which are relentlessly imperial. I have had to get used to the series of sizes 1/4, 3/8,7/16, 1/2. Sure, I can convert, and the digital caliper has a little button that does it for me.
BUT..
A worn out 10 TPI ACME on the cross slide just might get replaced with a 2mm pitch. I know that South Bends had some kind of trick compensated graduated dial that basically provided a metric lathe. There is the 127 tooth gear thing that converts the lead screw into a very close metric approximation, and I have seen some stuff about using unusual combinations of gears, and choosing selective gearbox settings that produce extremely close metric moves - closer than the tolerances most would need.

I will continue, for a while, to make metric stuff by multiplying by 25.4, but in the end, I will probably make one lathe metric, the other can live on in restored imperial splendour from it's heritage. The mill is already naturally metric. The collets, the vise, everything!

For a time, here in UK, some car engines were produced with M13 bolts that were deliberately given 1/2" AF heads, so that most imperial spanner sets would not notice the difference. Now THAT's "mixing it"! :)
 
My South Bend Lathe was made in France and is metric on all the dials which suits me well. Unfortunately it was made with an imperial lead-screw so while i only single point metric threads i am unable to disengage the half-nut. Were Whitworth lathes produced?
 
My South Bend Lathe was made in France and is metric on all the dials which suits me well. Unfortunately it was made with an imperial lead-screw so while i only single point metric threads i am unable to disengage the half-nut. Were Whitworth lathes produced?
I can understand the (French?) South Bend has an imperial threading lead screw, but I take it that the ACME screw on the cross slide has a metric pitch. How far does one turn advance, and how many divisions around the dial? Your lathe may have been produced "converted", or had a conversion done at some stage unless you had it from new.

I ask this because I am seriously considering "converting" mine, by giving it a 2mm advance ACME screw.

Re: Whitworth threads. The only difference to regular threads is to grind the tool angle to 55° instead of 60°.
Whitworths use TPI for thread pitches, just like any other imperial thread.
 
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I can understand the (French?) South Bend has an imperial threading lead screw, but I take it that the ACME screw on the cross slide has a metric pitch. How far does one turn advance, and how many divisions around the dial? Your lathe may have been produced "converted", or had a conversion done at some stage unless you had it from new.

I ask this because I am seriously considering "converting" mine, by giving it a 2mm advance ACME screw.

Re: Whitworth threads. The only difference to regular threads is to grind the tool angle to 55° instead of 60°.
Whitworths use TPI for thread pitches, just like any other imperial thread.
I apologize for the thread diversion. I had never thought about this to anything like the level of your questions. This lathe was made in the 1970s and is weird. I like it actually. One revolution of the handwheel reads at 10mm (diametrical measure). The cross-slide moves about 0.197”. Thanks for putting those thoughts in my head. I like that stuff.
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