Kurt Vise Root Canal

A few articles ago I wrote about a pleasant machinery surprise I found. The surprise was a nice four inch Kurt vise that came with my Clausing drill press for nothing. The vise was pretty hammered when I started working on it. Originally I thought it was an offshore knockoff and even considered trading it away for something else. Lucky for me I decided to give it a bath and take a closer look.

The vise was in pretty sad shape when I started in on it. The jaw mounting surfaces were whupped from clamping parts with no jaws. The handle is lost to who knows where and the replacement is welded in place no doubt to prevent its loss. A fine patina of sulfur based cutting oil residue rounds out the gruesome picture.

The moving nut has seen the business end of too many drill bits to count. One bonus here is the table of the drill press is relatively unmolested. Probably because the vise took the bullet for the team protecting the table. Look closely at the divits on the right side of the nut. They look a little wonky to me so I started picking at them with a awl. I was able to pop out a couple of loose fillings made of epoxy.

A few minutes in the dentist chair and now we have a clearer picture of the necessary dental work. I don't understand how somebody keeps drilling in a situation like this. The one hole at the top of the image goes halfway past the vise screw. I know now why the bozons patched the holes with JB weld or bondo. They had to keep the chips out of the screw or nothing would work.

Many of the edges of the vise were chowdered up like this. A trick a dutch toolmaker showed me a million years ago is instead of filing the raised burr off is to displace the material back into position. You will need a smooth flat faced hammer. Its important that the edges between the face and the side of the hammer are rounded so you don't get a bite mark if you hit off angle.

The trick is to hammer and direct the blows so the face hits flat. If your careful and work slowly generally you can push the material back into position pretty well. If you file it off its gone forever.

A little careful tapping and the corners are mostly back where they belong. Its going to take more than a little tapping with a hammer to get this vise looking good again.

The first step in fixing the Swiss cheesed vise nut was to make a copper mandrel to fit inside the threaded hole through the center. The purpose of the mandrel is so any weld metal doesn't get into the threads. The nut would be difficult to re-thread in the lathe because of its awkward shape and odd size and left hand to boot.

The copper mandrel fits in the threaded bore with a easy slip fit. I expect this to get a little stuck after the welding.

A short preheat and it will be ready for welding. Looking for something like three or four hundred degrees F or so. Hot enough to smoke the old cutting oil.

I'm TIG welding the holes with 1/8 diameter Ni-99 rod. Tungsten is 3/32 diameter Lanthanated DC straight polarity. A reader has been asking me what kind of current I'm running on some of these jobs so I set the camera up and took a picture.

I did it twice and the current was the same at 100 amps. The machine was set in the high range which is the upper scale on the right hand meter.

It took two filler rods to fill the cavities up to this point. If I was really a dentist this would be called a trans-cavity bridge filling.

While it was still hot It got wrapped in a fiberglass blanket and allowed to cool overnight. Next up will be the mandrel removal.

The next day I went to work on removing the copper mandrel. Driving into work I thought of a good way to drive it out by just inserting the lead screw and pushing it out. I was so happy I thought of an easy way to push it out I was thinking about it during the day.

It was a great idea for about half way. The mandrel stopped moving so I had go to plan B and get medieval on it. I ended up cutting if off short and drilling as big a hole as I dared in the now dead soft copper. If you haven't experienced dead soft copper and drill bits consider yourself warned. After drilling a pretty good sized hole through it still wouldn't come out so I used a jab hacksaw to split the copper tube that was left of the mandrel and collapse it into the hole. I didn't take any pictures of this process as I was annoyed and just wanted to get it done.

I did some sanding on the weld buildup to make it look more presentable. It least the holes are patched and no chips will get down into the screw and nut assembly.

The finished product. Not factory new but definitely better than usable. I made a set of steel jaws with a built it parallel step and vertical vee groove. Not a bad ending for a vise that was close to its expiration date. I called Kurt to ask if they had parts for this vise. I was told this vise is a very early model. The clues were the five inch width and the lack of a needle thrust bearing in the screw. This dates it to the dawn of Kurt history. A real relic.

Thanks for looking.

Tom Lipton

Three Dimensional Imaging Microscope

As part of a development effort on a new high field magnet design we are currently fabricating various parts of a prototype magnet for testing. The magnet is a hybrid design and uses a unique configuration to cancel and or minimize the some of the large forces that want to rip the magnet apart. We call this unique design a canted cosine theta configuration or CCT for short. This is a hollow bore superconducting design that we hope will lead to magnetic fields in the 20T (Tesla) range. So far the results are promising and fun to work on.

In these shots you see the basic configuration of the magnet. These are parts produced by the FDM process and were used to test groove geometry and winding potential. The cable Jim is inserting is a flat multi strand cable of rectangular cross section approximately 1mm x 3mm.

As you can see in the images the Niobium Titanium cable is insulated with a thin glass sleeve or overwrap. The idea is this isolates the wire from the magnet structure electrically. Part of our development project is to determine the groove geometry that protects the wire and insulation during winding and holds the wire securely during operation. Ultimately these might be built using Niobium-tin (Nb3Sn) which will allow higher magnetic fields to be achieved. 

Here is an aluminum test mandrel I machined on a 4th axis CNC machine. This particular sample was for winding and insulation testing for a high temperature superconductor (HTS). It is 1.50 inches (38mm) in diameter and the elliptical helical groove is a little over 1mm wide and 1mm deep with a round bottom. During winding tests the edge of the groove damaged the thin insulation so we tried a few quick shop fixes to try and soften the edge.

To help evaluate the changes in groove geometry we used a special digital microscope made by the Keyence company. We have one of these wonderful tools that we can use to examine and measure small features like this groove.

The microscope itself was designed from the outset to be portable and stand alone. The idea was to put an advanced tool out on the shop floor to collect meaningful information with the parts in situ. The variety of lenses allow the user to capture and measure with high magnification and great depth of field. The computer is fully ruggedized and integrated and easily portable with the actual scope. The stage is motorized and allows the computer to control the focus and depth up measuring feature. We didn't use the tilting ability of the stage for what we did here but it has been handy to create three dimensional images or peer into something off axis.

On the mandrel one thing we tried in the shop to gently deburr and soften the edges of the wire groove was wire brushing with a soft bristle wire wheel. The thought was that the bristles would break down the edge and not disturb the groove much.

In this image you can see the effect of the wire brush on the groove. The surface has been roughened by the brush. Unfortunately I didn't get any images before we brushed the mandrel.

Drilling down further at higher magnification we see the edges and lizard skin surface in better detail.

The microscope has a variety of measuring tools for distance, diameter, area etc. One of the more amazing things it can do is three dimensional images. The Keyence VHX does this by taking a set of images depth up and combining them to produce a three dimensional image that can be rotated much like a solid model.

The groove surface and top are both in focus giving a depth of field in this case of around a millimeter at 50x magnification. Images can be stitched together to make a larger seamless mosaic.

This is a three dimensional image of the curved pole section of the test mandrel.

The second thing we tested with this mandrel was a chemical etch to help soften the insulation scuffing corners. It consisted of an acid etch, much the same as a pre-anodizing treatment but without the caustic part of the anodizing process.

In this image you can see the overall improvement of the wire brushed surface in the earlier image.

Link to some other images taken with the VHX system.


Thanks for looking.

Tom Lipton

A pleasant surprise

For the people that have been following my YouTube channel you already know I recently bought a Clausing drill press. It came from my favorite source, a Craigslist private sale. I have been halfheartedly looking for a variable speed drill press to add to the shop stable. I missed a couple and another one was just too far away for its potential. This one popped up and I happened to be in the mood for a look see. So me and my friend Marty loaded up his truck and headed out.

 This one met all my drill press criteria and was still available. As you can see it is all there but dirty. Note the vise and XY slide on the table. It was a bonus with the machine and the subject of this article.

Like the rest of the machine the vise and cross slide unit were dirty and need some TLC. The vise handle was actually welded to the hex on the screw. This vise saw some real Bozon users in its history. So the first step in any refurbishment is to do a lot of cleaning and find all the secrets while you get to know the machine.

Initially I focused on the machine itself to get it in operable condition. This was mostly cleaning and new belts and lubrication of all the moving parts. I shot a series of three videos if your interested in some of the refurbishment details. So after it ran and was tested I started looking at the vise and cross slide that came with it. The vise was a mess. No jaws, drill damage to the nut etc. I consigned myself to just clean it up and set it up for use on the drill press without the cross slide.

Nice one! Not sure how I'm going to fix this one yet. For a week I walked by the vise and scraped for a few minutes then went and did something else. A few nights ago I started to clean in earnest and disassemble the vise. When I got the machine I saw the cross slide unit was a cheapco offshore model so I assumed the vise was from a similar supplier. As I cleaned the vise I saw some casting numbers in the various parts. I had a half thought this was a little weird for a cheap vise.

My next clue that something was strange was when I got a file out to take off some bumps on the center slot. It turns out this is heat treated and hard enough for the file to skate on the surface. By now I was intrigued and kept cleaning. The answer was revealed with the wire brush.

This made everything make sense. Here was my pleasant surprise. As part of the deal I got a four inch vise that costs more new today than I paid for the whole drill press deal. Its a little beat up but easily repairable and will make a good article. For readers out there that don't know Kurt vises. They are the defacto standard machinist vise in the United States for job shops and tool rooms. This particular vise looks old to me for a Kurt. The shape of the coolant drain slots on the side look different than newer Kurt vises and there were no needle thrust bearings in the screw assembly.

You can bet I'll spend a little time getting my new friend back in proper working order.

Thanks for looking.

Tom Lipton

Gloves in the machine shop

Well somehow I have managed to post a little over one hundred articles on this blog. I just want to take a second to thank all the readers that follow the blog, and especially those who participate in it with their comments. The feedback and interaction is what stimulates me to carry on with the blog project. Thanks again for your support.

The subject of this post has the potential to be somewhat controversial. What I want to talk about is wearing gloves in the machine shop. Many of you out there may have noticed that in some of the blog pictures or on my YouTube videos I am wearing gloves while operating machinery. I have received several comments asking about this practice so I thought I would explain it in more detail.

When I was an apprentice I got yelled at a few times for wearing gloves in a situation where it probably wasn't a great idea. Those old loud codgers were just trying to protect me which I thank them for. The typical metalworking shop is loaded with machinery just waiting to bite the unwary. They were doing their job and protecting me like one of their kids.

Not that long ago I did a shop study. The subject of the study was injuries to my hands while working in the shop. I actually called them insults but that's beside the point. As many of you well know in the course of working in a machine or metal working shop you expect a certain number of minor hand insults and dings as part of the job. As part of my study I recorded anything that happened to my hands during the course of working in the shop.

After some time had elapsed logging entries I reviewed the specifics of each insult. The object was to filter them into several groups. The first group was injuries or insults that would have been prevented by wearing some kind of a hand protection. The second group was insults that would have been greatly minimized by wearing gloves. And the final group were injuries that gloves would have not made any difference.

I admit this was a limited study conducted by a minor klutz. I will tell you there were no insults that gloves would not have made a difference. In other words everything that happened to me during the study period would have been totally prevented or greatly minimized. Also during this period there were zero close calls because of wearing the gloves.

Now before you jump down my throat and say how dumb this sounds lets talk about it. I've been working in metalworking shops for forty years now. I can say that I've done some pretty good dings to my hands over the years but they still have all the fingers and everything works fine. Also things have changed in that forty years.

When I first started in metalworking there were not a huge variety of glove options readily available. Thanks to manufacturing technology we now have a huge number of choices for personal hand protection for a large cross section of specialized  hazards. Hand injuries are quite common and some smart business people realized the huge potential market there was for hand PPE. In the old days you just used your leather gloves for everything unless it was cleaning the shop toilet. For that you shared a pair of somebodies hand me down dish washing gloves. There was a fifty fifty chance of a hole or leak in them to add to the fun.

So where I'm heading with all this is my opinion is the risks of wearing gloves around many types of machinery are very manageable.  Just having the right gloves on in the shop has a huge potential in reducing hand injuries and insults in the metalworking industry.

I have been experimenting with some gloves in the machine shop for more than a year now. I don't always wear them but I try to do it regularly and note the situations where my spidey sense tells me its a bad idea (like the belt sander) as well as when I note a positive effect like my hands don't cramp as easily from pinching small parts while de-burring. The gloves I have zeroed in on have some gripping abilities that enhance  your hand grip and allow you to use less pressure or apply more pressure when needed.

The gloves I like and have settled on for most work are the Maxiflex Ultimate. These are a close fitting precision dry handling glove coated with nitrile foam. The dexterity is so good you can pick your scale off the bench or floor with them on. Some Airgas welding supply shops carry them and S&S safety solutions in Martinez CA stocks them.

The small injuries that occur most frequently are things like getting cut on a burr or chip, bumping a sharp tool  bit or insert while handling a part in the machine, dumping scrap in the bin, unfolding a band saw blade etc. All preventable with gloves. As machinists and metalworkers we very rarely get cut from any rotating member on the machine. Those old guys yelling at us did their job well on that count. We get dinged by bumping into things, reaching for things, in other words all the other things besides the rotating machinery.

Nobody blinks an eye when a chainsaw operator puts on a pair of gloves. Why do we get so nervous when a machinist operates a milling machine with a gloves on? Neither person is touching the moving cutting edge right? There are dozens of industry examples of people wearing hand protection while in close proximity to rotating machine parts. The general shop rule is to never directly touch a moving surface, blade or machine member with your hand. Well if you adhere to this guideline when wearing gloves you will stay relatively safe.

Now there are lots and lots of things I would never do with gloves on in a million years. But after forty years experience I can spot these situations with an excellent success rate. Most of that comes from having made many of the mistakes that hurt and learning from them.  So if you are a beginner then I suggest you proceed with caution. If something bit you before then pay attention.

A funny side story about fingers. I had a welding student many years ago that came to class with one of his fingers swathed as only the medical industry can swathe something. When we asked him what happened his story sent shivers down my spine.

This particular student worked in a structural steel shop as a helper of some sort. He was helping rig a large I beam for rolling over with the crane. I guess the sling was offset from the center of gravity so the beam would  roll when they lifted it. Well he somehow managed to get his finger between the table and the beam. The thing that gives me the willies was how he described the damage to his finger.

When he related the story to us I asked the question, Ouch, that sounds bad. What happened to your finger? He paused for a second thinking about it and said, "Well have you ever stepped on a hot dog?" Apparently the end of his finger burst out much like a stepped on hot dog. Youch! I can't eat a hot dog now without thinking of that story.

Now that is an example of an event that gloves would not have made any difference except getting less blood  on the workbench.

The gloves I prefer for machine work I discovered by accident. We were in the process of moving and between my wife and myself must have 200 cubic feet of books that had to be moved. Now if you have moved you know not to load book boxes very heavy or else you kill yourself. What happened was my hands naturally dried out handling dozens of boxes. Take a look at the UPS drivers hands for a clue as to what happens when you handle cardboard boxes all day long.

After work one day we were loading a truckload of boxes to take over to the new place. I had a used pair of these gloves that I forgot to take out of my coat pocket. On a whim I put them on just to keep my hands from going UPS. I noticed the advantage immediately. The gripping force to hold the box securely dropped to roughly half. It was like spider man gloves for boxes. After having this dramatic example I started experimenting with the gloves for all kinds of things, like working in the metal working shop.

So here we are fast forward. My experience with wearing gloves in the shop has been manageable, positive and hand healthy. Here are some of the positive benefits I have seen from wearing gloves in the shop.

• Lower gripping force required to hold items.
• I can tighten the drill chuck significantly tighter by hand wearing these particular gloves.
• I can carry more weight in each hand than I could before.
• Hands stay warmer and cramp less without the sweating.
• Hands stay cleaner in general. Nice when you have to run to the office and do something.
• Cuts and nicks are reduced to near zero
• Vibration isolation

The vibration isolation properties are well worth it. If I have any amount of jitterbugging to do my fingers end up feeling like their electrified for the rest of the day. Wearing gloves reduces this to nothing.

This article is just my opinion and observations from actual shop testing. Its okay if you disagree. I'm not forcing anybody to drink my flavor of Kool-aid. Gloves in the shop is not right for everybody. So in closing I suggest you conduct your own test and see if you find any similarities with my observations. Report back your own findings and opinions and please be careful when testing and don't do any of the following things,

Belt sand. Any converging gaps that the tip of the glove could get sucked into are bad. Plate rolls and moving chains and sprockets fall into this category.

Grind tiny tool bits on the bench grinder.

Don't polish on the lathe by gripping the paper directly to the work wearing gloves.

Don't stick your finger in a rotating bore to check the finish. In general don't touch anything rotating. But that's already a standing rule.

These gloves are completely useless for hot stuff.

Thanks for looking.

Tom Lipton

Double Curved Handwheels

There is something lacking in many modern mechanical components. The plain utilitarian aspect is partly driven by cost considerations and manufacturing optimization practices. Why do we fall in love with old machinery and equipment? Many old machines are visually pleasing as if the designers really cared that the visual impact of the machine was an attribute worth investing in. Sadly most of the demise of art in machinery is cost and profit driven. We can all appreciate nice looking machines but are voting is generally dictated by our checkbooks.

I was talking to an engineer friend of mine on this very subject and he had a pretty good line of reasoning worth sharing. Before the invention of automatic machine tools many machine parts were cast in steel or iron. All of these parts had to have foundry patterns made for them at some point. There is a  big fundamental difference in the manufacture of something like a machine hand wheel that is cast and one that is machined. The hand wheel is just a simple example of the potential for adding some pleasing aesthetics to an otherwise mundane part.

When a part is cast the pattenmaker makes the pattern one time. This one time effort yields thousands of parts with all the features and embellishments the patternmaker puts in. The fundamental effort to produce the part is the same for all the parts cast from that pattern. Whatever the extra cost for the time the patternmaker spent to make the part beautiful is spread over the cost of the thousands of parts that follow.

The modernization of some of these manufacturing processes has eliminated most of this decorative aesthetic in machine parts. Modern generally means spartan, or clean crisp simplified lines. Is it better? I like the modern style when its well executed with thought behind it throughout the article or machine.

But what I wanted to talk about in this article is something that old time machinery buffs all over can agree on. Who doesn't like a nice old time cast iron hand wheel or pulley? In particular one with double curved spokes. There is something cool about the curved arms and legs of a simple article like a wheel that give it life at a basic level.

A simple valve handle with double curved spokes. It looks poised to turn all by itself. All the operator has to do is give it a little nudge.

 These pulleys were at a recent flea market for $400 each when I passed them in the morning. When I walked by a couple of hours later they were both gone. Somebody made something cool out of them.

And we finally come to the actual subject of the article. This is a handwheel for a fine arts etching press. The hand wheel is the signature part of a high end etching press. The large wheel diameter gives the operator fine control of the printing process with low human power input. Most presses have some kind of gear reduction to further reduce the force on the operator. A few presses have hand wheels in the five foot diameter range.

About six years ago I built a small etching press for my wife to print small etching plates with. It was really a stop gap for building her a larger press. Well the time has come to get moving on the big project for real. I have laid the groundwork for building the press in my home shop. A few items like the lathe were selected on their ability to produce the needed parts for the machine. A crane and forklift were added for good measure and spine health. I figured I might as well start with some of the more complicated bits of the machine. The hand wheel and drive system are first on the list.

I wrote a blog article and posted a YouTube video of the heart of the system. The press I'm currently working on will be larger than the French American Tool press in the picture above with a much more interesting handwheel. The current design projections put the final weight around 3500 lbs to put the project in perspective.

Here is the layout of the handwheel in Solidworks. My goal was to try to duplicate the graceful tapering curves like we see in old cast iron handwheels. I set the Solidworks sketch up and drove some of the proportions with equations to allow me to create handwheels of almost any diameter by changing one number. The layout is interesting in how the arc tangencies are created. If folks are interested I will do a separate article describing how to do it. Post a comment if this is something you would like to see.

Here is the Solidworks model of the handwheel sub assembly and Wabble drive for the press. You can see the motif of the press is the curved spokes. The arms of the Wabble output follow the same layout.

Here is the beginnings of the handwheel for the Ox tool etching press from the layout above. Looks kinda dinky right?

For those of you that have been following the steady rest built on YouTube you can get a sense of scale now. The handwheel is four feet in diameter and and inch and a half thick. The spokes are five eighths thick. When I had the handwheel sections burned out by Nowell Steel in Antioch. I threw in the steady rest profile while they were cutting inch and a half plate. I need the steady rest to machine the large solid rolls for the press. The steady rest that came with the lathe can only handle seven point eight inches in diameter so I had to build a larger one.

I was worried about the open C shape moving around when they oxy fuel burned the profile so I had it cut larger to allow me to machine the profile accurately. I don't want the rim to run out much so it will have to be carefully put together. Here I am preparing the blank for machining. I weld it to a backing bar that is then clamped in the vise allowing me full access around the profile with a tool.

Even in steel not much weld is required. You just have to get it in the right place and not cut it away!

Here is one segment after profiling. I used a one inch diameter high speed cobalt fine pitch roughing end mill made by YG tools that I cant say enough good things about. Two passes three quarters deep and approximately a quarter inch on the periphery. Three hundred fifty rpm at six inches per minute feedrate. One tool removed maybe forty pounds of material and is still fresh as a daisy.

Here is the finish left by the end mill. I have cut off the backing bar and smoothed the welds. Eventually the rim will be rounded off so it feels better in the hand. These joints will be weld prepped and then blended for an invisible seam.

In this shot you see the wood sample I gave the "customer" for approval of grip size and rounding. I have some serious grinding in my not too distant future.

All five segments sitting together on the weld table. It measures right on the forty eight inches. There will be notches cut at the rim joints to insert the spokes to make a rabbet joint. Next will be an assembly fixture to make sure the segments are aligned in as good a circle as they can be for welding.

Eyeballing the center hub material for the handwheel at one of my favorite scrap yards Bataeff Salvage in Santa Rosa.

Thanks for looking.