Brass Clamping Screw for Starrett V-Blocks

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.

Thanks Paul! We've added your V Block Clamping Screws to our Metalworking category, as well as to your builder page: Paul Jones' Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/v-block-clamping-screws"><img src="http://www.homemadetools.net/uploads/142419/v-block-clamping-screws.jpeg" /></a></div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/v-block-clamping-screws">V Block Clamping Screws</a> <span> by <a href="/builder/Paul+Jones">Paul Jones</a></span> </div> <div class="tags">tags: <a href="http://www.homemadetools.net/tag/v-block">V-block</a></div> </div> </div> </div>

Nice work Paul. That patina is beautiful and hopefully your brass will catch up with it over time.

Would have thought a standard 1/4-28 would have worked but obviously they chose something slightly under although the machinery's hand book says the min. maj. diameter could be as low as .2392 for a class 1A...not so good for a V-block hold down. The oddest threads I ever worked with are the grip screws for a 1911 which are .1500-50 UNS-2A THD which screw into a threaded bushing with .2360-60 UNS-2A THD into the frame.

I guess if your name is Starrett or Browning you can do what ever you want. ~¿@ Nice work on yours and thanks for sharing!! ~PJ

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Originally Posted by PJs

I guess if your name is Starrett or Browning you can do what ever you want. ~¿@ Nice work on yours and thanks for sharing!! ~PJ

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Or Brown&Sharp :)

Beautiful work as always Paul.

I picked up a matched set of Brown&Sharp 749 v-blocks in a garage sale here for 50c! I guess the old guy died and the daughter was having the garage sale. There was all kinds of odds and ends. I found three little clamps each for 50c, and those v-blocks were in the absolutely crumbling original box. So I couldn't see when I picked up what they were. When they tumbled out of the rotten box I couldn't believe what they were when I looked for the marks. Everybody looked up when I called my wife over and said look! She had no idea why I was so excited and neither did any of the other junk pickers. They had no price on them and when I took my hand full of stuff up the woman looked at me and I said how much? She said if you can tell me what they are I'll give them to you for 50c. When I told her they were v-blocks used in machining she just stared at me. I guess trying to see if I knew what I was talking about. I put on my best poker face...and stared back, she said $2 for everything. I wish I could find more deals like that.

C-Bag,
You don't find deals like that too often and great story. I like B&S tools and have Mics with the lever locks made by Brown & Sharpe. I was looking at my old Starrett boxes for my V-blocks and these were marked $8.25 from Ernst Hardware in Seattle. I remember buying these in the early '70s when it seemed like Boeing was laying off half of Seattle (there was a billboard reading "Will the Last Person Leaving SEATTLE -- Turn Out the Lights" posted near the Sea-Tac International Airport. I offered the store clerk $8.25 for both boxes of V-blocks and he said yes. By the way $8.25 in today's dollars can be calculated at https://www.measuringworth.com/uscompare/ and you will see that $8.25 is more expensive than you would think.

PJs,
The old Starrett tools seem to have odd screw sizes and probably just because they can. I was going to use a standard 1/4-28 die to make the clamp screw threads but I doubled checked with my electronic caliper to make sure. At first, I thought my caliper had reset its zero point when finally I realized Starrett had an odd screw size. Of course Bozo came to visit me when I made the second threaded part on the lathe. I machined the major diameter at 0.233" instead of 0.223 by misreading the digital mic and then single point threaded the part only to find the thread wouldn't fit. I learned to never release the lathe clutch or gear settings until you can check the threads. I was able to turn it down to the correct diameter and finish the thread without any problems.

Thanks for the comments, Paul

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Or Brown&Sharp

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Lol...I've always liked them too and never had any issues with them. I picked up one of their lesser quality (Standard Gauge) 12" digital height gauges a year or so ago and its been great and repeatable, no complaints and my ancient 5tenths DTI just keeps on ticking! Great Story and awesome price, C-Bag.

Paul: Your story was great too and almost as good a price. The current Starrett price is $108 and not nearly as pretty. Interesting web calculator which relayed the difficulty in calculating it but they came out half of current¿ I remember the Big Boeing cut backs around then and that saying. My uncle worked for Douglas in Long Beach for 30 years and they had similar issues around then.

Glad you were able to recover the piece they do look great with your vintage blocks! Thanks for sharing and the good stories! ~PJ

I don't know which is more astounding Paul. Getting BOTH sets for $8.25 or finding them in a local hardware store!!!

I was really lucky that this old character for whatever reason liked me and whenever he would find some deal on measuring equipment he'd save it out for me. He was making his living by wheeling and dealing in swap meets here in the Valley from Bakerfield to Redding. My old 0-1, 1-2", 2-3" Starretts along with an ancient Starrett inside mic set I got all from him in the '70's. The one that got away was a Brown & Sharpe mic set from 0 to I think 6" that was one frame with all the different anvils and adjuster along with the gauges for each size. Seems like he wanted something like $75 for the set in the original box. He must have tortured me with that for months, but I just couldn't see where I'd need it that big, never mind I was making peanuts as a young VW engine mechanic.

I think I've mentioned it before, but there are a lot of small manufacturers here that retire and die. So periodically amazing stuff comes up in yard sales, CL, and weird places like antique stores. Some of it is reasonable, some of it is sky high. But every once in a while I score. But in the grand scheme of things I think you made out the best.

BTW, Bozo is a LOT kinder to you than me! You just had to cut it down, usually I have to toss it.

I saw a neat protective brass cap to a V-block clamping screw while watching the YouTube video by Suburban Tool Inc about their jig grinder. The brass cap just slips over the tip of the steel clamping screw and is a much easier solution to my version using a brass replacement to the clamping screw. I made a pair of the protective brass caps and like how these work. Each cap is 0.375" long with a 0.375" diameter, bored to fit the steel clamping screw diameter and turned down with smaller diameter end for clamping.

Attachment 8657Attachment 8658

How are they held in place? I wouldn't want to have them falling off the screw.

Another approach is to drill the end of the screw and drive a short piece of brass rod into the hole.

Personally I like the all brass screws, Classy!

I've used both methods depending on the application. The cap type can be threaded and use loctite, but that would be tough because of the odd thread and shallow inside threading. I have also turned the end of the screw down to form a shank and make my cap to fit slightly under the OD of the thread then used 680 to hold it on...that way it will come out of what it is screwed into. Did that on my drill press quill slot screw to fit the key way better and ride smooth.

The Pin type is easy too and can make a top hat design :hattip: that is just under the OD of the thread. I made a Delrin one for the tail stock screw on my mini to extend the taper break loose...it was a press fit and stays in fine because I over-sized the pin skosh and press it in...compressing the Delrin.

Thanks! ~PJ

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.

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Originally Posted by 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.

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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.

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

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.

Attachment 8675

I will post the finished parts.

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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.

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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

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.

Attachment 8705Attachment 8706Attachment 8707Attachment 8708Attachment 8709Attachment 8710

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

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

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Originally Posted by Paul Jones

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.

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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.

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

When I have to thread to a shoulder I like to do so from the shoulder out instead of from the end to the shoulder.
This is a problem on lathes with threaded spindles though since the tool is mounted upside down and you have to run in reverse