One advantage to cheap Chinese tools.

K

Kevin R. Cashen

Joined
Sep 9, 2003
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For two years now I have needed a special port to mount my camera on my trinocular microscope, I had hoped to get an old trinocular head off e-bay and salvage the part that way. Then recently I got a nice inverted microscope designed for metallography that even came with its own 35mm camera mounted on it. After removing the film dinosaur I saw the port had 37mm threads and there was a chance of mounting my digital directly to it with just one adapter.

Of course there is no such adapter made on planet Earth, (a 35mm male 1mm thread/37mm male .5mm thread), I found this out after checking every camera supply source I could find. I was just about ready to take my checkbook to a machine shop with a CNC lathe (who else is going to do these odd metric threads), when I was walking through a scrap yard Wednesday and saw an odd shiny cylinder. I picked it up and measured it to find that it was better grade aluminum that matched the two outside diameters of the needed adapters, one solid rod inserted into another thick walled tube so snug that they would barely separate.

It is so odd that I ever find something so exact to what I need, and it was the only scrap of aluminum in the entire yard, I thought it may be a sign of some kind that I may be able to get this thing done myself. Then I thought of my cheap Chinese mill/drill/lathe combination machine. Years ago, when I bought it, I sprung for the heavier model that had an automatic feed on the carriage. I remembered a package of extra parts stuffed behind the thing gathering dust. Eureka, gears for cutting threads! And since it was a cheap Chinese machine- the thread sizes were all in metric!:D

I don’t know a thing about this stuff so I put the parts that needed threads under the microscope and measured the threads in 1/100mm, and this afternoon I tried my hand at turning threads. By 11:00 P.M. this evening I had all the adapters made and working. This thread turning stuff is cool and pretty handy! I think I will keep my cheap Chinese machine around a little while longer.
 
Cool deal on making the part you needed. let me tell of my cheap foreign tool success. I have a dewalt electric die grinder. I lost one of the collet wrenches so I haven't been able to remove the tool in the collet for two weeks. I was in the hardware store buying some self tapping screws and on the sale table there was a two pack of combination open end box wrenches. The sizes 5/8" and 1/2" made in India. $1.00 I took them home and thined the open ends so they would fit the slots on my collet, adjusted the throat size fo fit the collet and volla! new collet wrenches for a buck!
 
Kevin R. Cashen said:
And since it was a cheap Chinese machine- the thread sizes were all in metric!:D
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Almost the entire world works in metric...even the real expensive German machines... imagine that :eek: :p
 
But here in the States metric is the exception. Most of the older machine shops I called couldn't handle it because of the metric thing, and referred me to places that had CNC lathes (the whole proposition was sounding expensive). I meant no slight by the "cheap" descriptor, but it differentiates from the two options open when buying a lathe on a knifemakers budget if you want something other than the English system. Most bladesmiths will not be able to afford a German lathe but the Chinese ones are more affordable than ones not in metric.

Truth be told, I like the metric system, it is a heck of a lot easier on us mathematically challenged folks. If we would have gotten draconian about it and went cold turkey back in the seventies I would be happy with mm today. It is the darned conversions, that I hate. It is then that I am not just challenged, I am mathematically crippled! Due to this I have always hated the mm dials on the mill portion of the machine, in a country of .001" they were virtually useless to me. But then they were never that accurate anyhow because it is a cheap Chinese machine ;) .
 
Successful single point threading certainly does give one a sense of confidence and well being eh? Great job!
 
It's cool to be able to make your own tools ain't it? I've got a threader on my lathe but still haven't figured it out yet. Got the extra gears to cut right and left handed threads and haven't installed them yet. One day maybe.:confused:

We actualy started with the metric system in the late 1700's, but then switched because our gun supplers at the time used the inch system. If I remeber rite we were using the metric system because french weopons used it. After we got along with England again we switched to standard. Something like that anyway, still sleepy.
 
Will52100 said:
It's cool to be able to make your own tools ain't it? I've got a threader on my lathe but still haven't figured it out yet. Got the extra gears to cut right and left handed threads and haven't installed them yet. One day maybe.:confused:...
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Will, I would encourage you to just play one afternoon. My bag of gears sat for all these years unused because I thought the whole threading thing was beyond me. I had heard of how advanced an operation it was and how complicated others made it sound, so I didn't even bother attempting with my limited machining skills and know how. It was 2:00 in the afternoon when I pulled that dusty bag out and it was around 10:30 p.m. when I had two new adapters with thread pitches I had never seen before, one so fine I barely thought it was possible. I was so excited with the results (after searching for 2 years for a way to get such adapters), that I posted this thread, regardless of its mundane nature.

Mike, taps and dies are the way I have done it on smaller parts for years, but finding a die to do a one time job of a ring 37mm in diameter with a thread spacing of .5mm, simply wasn't practical. I am tickled with this method because of its versatility. With one tool I turned down a cylinder 35mm on one side 37mm on the other and then put 1mm threads on one and .5mm threads on the other. Then, still using the exact same tool, bored out the inside diameter to the precise mm I needed to eliminate any pesky vignetting in my micrography. It can handle any diameter and any thread pitch simply by switching a couple of gears. I love my taps and dies, but I haven't seen one yet that can do all that :D . All I had to do was take the leap one afternoon and figure out how to do it.
 
Kevin, you really shouldn't use a threading tool for general turning. You were using a threading tool right? Do you have a fish tail? A fish tail is a small gauge about like 2" of steel ruler stock that has a couple 60 degree Vs vut in it. The one on the end is for checking your cutting tool for correct shape when grinding or sharpening a cutting tool. The V on the side is designed to use to make sure your threading tool is perpendicular to the shaft you're threading.

The one pictured on the left is the most common one:

http://en.wikipedia.org/wiki/Fishtail-Center_gauge

A general turning too has a much broader radius on the end and a different rake than a threading tool.
 
J. MacDonald said:
Kevin, you really shouldn't use a threading tool for general turning. You were using a threading tool right?...
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As I said I am no machinist, not by a long shot, so I do not have the gauging tool you describe, but I did find out before hand that I needed a 60 degree thread cutter vs. my regular turning tools. When I mentioned that I used the exact same tool for the different operations, I meant the lathe was all I needed and I never had to unchuck the work. Being a complete newbie to it all, I found it very cool:) .
 
That is wickedly cool! If you're sucessfully single point threading on a lathe, you're a lot closer to a machinist than a lot of guys that go by that title. Find yourself a fish tail. It's a great cheap addition to your shop and will help you set up right for threading. Put teh flat side against the work, then use the V on the opposite side to help alight your toolpost so that the cutting tool is properly aligned. If you want to really do it right, before you do all that, rotate your compound rest (top level of carriage) to the right 30 degrees (use protractor if the lathe is not equipped to indicate this). Then set your cutting tool up. This way when you're feeding the tool in to take your second pass, you're feeding in to the forward cutting edge instead of feeding in perpendicular to the workpiece, thereby engaging both sides of the threading tool.
 
It shouldn't be as bad as you might suppose for a CNC'ed part. It would take all of about 2 minutes to program, and if the right tools are in the lathe, it would take a couple minutes to turn. I've made some really crazy threads for some pens I've made. Since I always have a .500" carbide drill in the lathe, I designed the internal threads in a pen to utilize that hole without additional boring. It's something like .543" OD threads on the mating part. The CNC doesn't care, metric or English, something standard or something strange. I was surprised to get triple lead threads in titanium that worked well on the first try. I also made some 8mm x .5mm pitch taps for the nibs for my pens. Being titanium, they're not as hard as the ones you buy, but they work fine in the brass nut that I tap with them. Fine sizes like that are very hard to come by.

The Chinese lathe sounds like it worked well for you though.
 
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