Brass Clamping Screw for Starrett V-Blocks

[C-Bag]

yup, all the above. I have some UHMW laying around that I'll have to play with to somehow accomplish what you guys have done.

I'm still trying to work up the guts and the project that makes me have to learn how to thread on the lathe. It's very inspiring to see the great work you, PJs, Paul and Marv do. One day I'll conquer the threading boogyman but it's too much fun watching for right now. Gotta luv this site and U tube. Thanks guys for all the great ideas.

[mklotz]

yup, all the above. I have some UHMW laying around that I'll have to play with to somehow accomplish what you guys have done.

I'm still trying to work up the guts and the project that makes me have to learn how to thread on the lathe. It's very inspiring to see the great work you, PJs, Paul and Marv do. One day I'll conquer the threading boogyman but it's too much fun watching for right now. Gotta luv this site and U tube. Thanks guys for all the great ideas.

Recommendation...

When you set out to learn single-point threading, use garden variety PVC pipe as your stock. Dead cheap and, if you screw up, it won't damage the machine. Especially true when learning to thread to a shoulder.

[C-Bag]

wow, thanks Marv! That's a great tip, never would have thought of that.

[Paul Jones]

PJs - Nice modifications for the lathe tailstock ejector rod using the Delrin. Yes, prefer the brass screws.

Marv - The brass caps can (and do fall out) when setting up parts in the V-block. I will try machining a small internal O-ring groove in the bore of the brass caps as a way to hold the cap onto the screw threads. Last year I bought from eBay for $36 six of the Micro 100 solid carbide boring bars for machining very small internal grooves. Great price but I had no immediate project. Here is a photo of the groove cutting boring bars.



I will post the finished parts.

[PJs]

I will try machining a small internal O-ring groove in the bore of the brass caps as a way to hold the cap onto the screw threads. Last year I bought from eBay for $36 six of the Micro 100 solid carbide boring bars for machining very small internal grooves. Great price but I had no immediate project. Here is a photo of the groove cutting boring bars.

Thanks Paul those mods made a world of difference to the tail stock operation.

Very cool boring bars at $6 a pop for carbide! The idea of an O-ring is great and good for other applications as well. Look forward to seeing what you come up with. Thanks! ~PJ

[Paul Jones]

This is my solution for holding the protective brass caps onto the steel clamping screws for the V-blocks. I used the two brass caps shown above and machined an internal O-ring groove for a small 008 Buna N rubber O-rings. The O-ring in the brass cap provides just enough snugness to hold the cap in the screw thread but is easy to put on and take off.

I happened to have the tiny Micro 100 solid carbide boring bars for cutting small O-ring grooves and these made the job very easy. I used my modified Unimat lathe for the machining work using an old E16 collet holder to hold an ER16 0.375 ID collet. I don't recommend using ER16 collets in an E16 collet holder but it works (FYI -never use a ER16 collet holder to hold E16 collets). The O-ring in the brass cap provides just enough snugness to hold the cap in the screw thread but is easy to put on and take off.

[PJs]

Nice looking caps, Paul. The O-ring was a great idea and seems to work good.

I had never heard of E16 collets before but did a bit of research and seems they are the forerunner to ER16's that don't have the cap lock groove but similar tapers. Also found it was an option for the Unimat's and can be found on ebay sometimes. I can see why you wouldn't want to put an E in and ER holder...likely wouldn't get it out. Always great to learn something new. Thanks for sharing and the great pictures! ~PJ

[Paul Jones]

PJs,
The more modern ER16 collet chuck clamping nut has an ejector ring that can damage the older style E16 collets. The E16 collets do not have the special groove for the ejector ring. The ER16 collets were first developed in 1973 have many improvements over the E16 style such as 16 side slits vs. 6 for a much wider range of clamping diameters per collet. Unfortunately, the Unimat SB and SL lathes adopted the E16 collet design because the ER16 design was not available. I am considering making my own ER16 collet chuck for the Unimat M12x1 spindle thread (this has been completed and see http://www.homemadetools.net/forum/u...6880#post67090 ).

Thanks for the feedback,

Paul

[rasta]

I have a two sets of the twin pairs of Starrett 271C V-Blocks. I find that many times I am adding a copper shim to protect the parts clamped in the V-blocks. I decided to make a new set of brass clamping screws as an alternative to the copper shims. The V-Block sets were purchase new in 1970 and each block has a beautiful mottled-brown finish from the color casehardening process. I don't think Starrett uses this type of casehardening technique on the current 271C V-Blocks.

Each set of V-blocks comes with a forged steel clamping yoke threaded for screws with a 0.223” major diameter and 28 TPI (the 3-wire method of measuring calculates a major diameter of 0.224”). I think the current V-Block versions use screws threaded 0.187-32. The brass clamping screws are made from 0.500” dia. C360 brass and single point threaded and knurled on the 12” swing lathe.

That color is typical of Cyanide hardening , done many hundreds of parts that way , in an old forge when I was apprentice, back in the middle of last century...nowadays
very hard to find the stuff.

[Ralphxyz]

I have often bent steel screws with my V blocks. Especially with round stock if the screw hits slightly off center the screw bends.

Ralph