Discussion in 'Gunsmithing and Repairs' started by KY DAN, Apr 3, 2019.
Really cool fixture! Aren't harmonics fun.
For smaller work I really do like the 7X series lathes produced by Seig. I have turned countless small, precision parts on lathes like this over the years such as screws, firing pins, tumblers, reamers, bullet mold cherries, etc. I teach, among other things, introductory machining classes and my university lab is equipped with six 13" Clausing Colchester lathes which are great machines. I also purchased eight 7x16 bench lathes from Little Machine Shop about three years ago and love them for teaching students the basics of lathe operation. For anyone who knocks the durability of these machines consider that these machines are exposed to about 200 students each semester, many of whom have never operated any type of machine in their lives. They need to be adjusted from time to time, but I have not had any failures to date on them. Even when students have been taught how to work with the Clausings many of them still return to the bench top lathes for smaller parts. Most of the people that I find who object to the smaller equipment are either those who have had no experience with them, or simply are doing work that is far outside of the work envelope of these smaller machines. Used within their limitations they can be exceptionally accurate and useful tools. Also, to the poster who said the 618 is preferable, I own two of them and, while I do like them, they are not anywhere close to being as rigid as the Asian 7" lathes.
That would be me, and that recommendation is based on having owned the 7x import machines, and the fact that I use a 618 every day in a professional capacity.
The 7x10, 7x12 machines do have a more rigid bed; they are much shorter. The 7x14 & 7x16 you'll find more comparable. From there, however, it goes down hill.
-The 7x tailstocks are tall & wiggly with "tap it around" adjustment rather than a screw like the 618/101.200 and other proper lathes. Very difficult to achieve and maintain center with them.
-7x machines use a potentiometer variable speed driving a cute little PMDC motor, have no power at low RPM (not a lot up top, either). The 618 can run real 1/3 HP or even 1/2 HP stand-alone motors, and the back gears give it real power at low RPM.
-The 618, being a belt drive machine, is far smoother through it's 60-3000 RPM range than the geared 7x with it's 150-2500 range.
-Though it has flat ways, the 618 has a wider carriage that can be tightened on both horizontal & vertical axes, vs. vertical only with the 7x series.
-The 618's thread range is 8-96 TPI, vs 12-52 TPI on the 7x. While pitches above 48 are seldom needed, that higher range translates to slower power feed rate capability, meaning much smoother surface finish.
-Compound angle marks are part of the carriage and compound on the 618 and are accurate, rather than screw-on pieces that have an error margin on the 7x. Compound angle adjustment is far faster & easier on the 618.
-Cross slide & compound knobs have a nasty tendency to loosen up on the 7x machines. This is a non-issue on the 618, and the indicator dials on the 618 also stay put.
The 7x do have a larger spindle bore, but at .75" vs. .55", neither is big enough to be very useful. Some argue the virtues of MT2 vs MT1 tailstock taper, but it makes no practical difference on machines this size, and the 618 tailstock can be reamed to MT2.
Neither machine has power cross feed, and both will need a QCTP upgrade, so nothing to compare there.
If one buys an old 618, they need to go through it, clean it up & tighten it. If one buys a brand new import 7x, they need to go through it, clean it up & tighten it.
A 7x10 was my first lathe, and I quickly learned why they're inexpensive. The half nuts broke early on, and the crank handles for both Z axis and tail stock broke out of the wheels. The carriage gib plate fractured all by itself, had to make a new one from 1018 steel. I also stripped more than one plastic gear trying to use power feed on steel parts.
As I became a more experienced machinist, the flaws in that lathe became more numerous and glaring.
My 618 was already 50 years old when I got it, and has seen far more use without any broken parts. I use it primarily for finish work, cutting everything from brass & aluminum to hardened martensitic or PH stainless steels and 6/4 Ti. It holds better tolerances than the 7x with higher finish quality. I did opt for an oversize AXA QCTP, made an oversize compound dial for it, and set it up with variable speed electronic power feed using an 80 RPM gear motor that gives me 1.1-4.8 IPM feed rates. Also switched to a 5" 3 jaw, as the original 4" didn't get enough bite on tougher stainless parts with small contact area to keep them from being ripped out of it taking heavier cuts. I would choose a decent 618/101.200 over an import 7x every time, even at considerably higher cost.
I agree with some of what you say when speaking of the lathes sold by Harbor Freight and some others, the Hi Torque lathes sold by Little Machine Shop have much better motors, no headstock gears, to name a few. They are much more capable machines. I would also add I use these machines with introductory machining classes every semester for the past few years. They are run hard several hours a day by students who are not always that gentle. Other than routine maintenance and adjustment I have had no major issues with them. We did change out the stock screws with the enhancement kit that LMS sells, a very worthwhile $20 investment. I do not believe that the 618 lathes would hold up as well. I like the 618 lathes and have ended up with two of them over the years, they are nice machines but having worked with both I still say the 7X lathes are the better deal.
I just picked up an 1982 model Jet 16 Mill/Drill and am currently learning how to use it. I’m planning to get a Grizzly 12”x36” lathe for Christmas. I’ve dabbled into gunsmith work for years and now that I’m close to retirement I want to get my shop outfitted for custom gun work. Possibly next year a nice laser engraving machine.
Take the $3,500 or so you'd spend on that Grizzly and shop around for a nice older Lagun, Leblond, Clausing, Southbend or other quality machine. I know it seems like I'm really down on the Chicom stuff..............and I am, for good reason. They're for beginners or hobbyists who don't want to spend the money for new, quality machines and lack the know how or gumption to evaluate and/or recondition quality used machines. Trust me, the time you'll spend bringing a well used or neglected but serviceable American or European machine back up to par will pale in comparison to the time spent dealing with crappy finishes left by a rough, geared head machine like the G4003. If you're just doing personal stuff, hours spent cleaning up rough cuts and chatter are something you can spare to save on equipment. If you plan to make money doing machine work, though, you're upside-down from the start with mediocre machines.
As for laser engravers, it depends on what you want to do, but while they can produce some really nice detailed images only a few tenths deep, heavier engraving tends to look like crap. Before you spend the money on one, do a lot of research on the results people are getting in the types of materials and at the depths you'll be dealing with. And for the record, any laser engraving on the Titanium tubes I provide for form 1 suppressor guys voids the warranty; laser engraving in open atmosphere embrittles Ti in the HAZ, must be done in an inert chamber. Just something to keep in mind if you may ever work with Ti.
Being a retired machinist/toolmaker I believe the smallest I would consider is a 10" lathe. There is a lot of old American iron available, you have to look and be patient. The gov't. sells its surplus through govliquidation.com. I purchased a very complete Sheldon 10" x 54" lathe from them. It weighs about 1200 lbs., 1-3/8" spindle bore, taper attachment, quick change gear box with a full set of change gears for cutting Metric threads. It came with a full assortment of ancient cutting tool holders and tool post. About the only things I have purchased for it has been a modern quick change tool post, tool holders and cutting tools.
Good info, I’ve seen some good used machines at reasonable prices, it’s gett them from there to my shop that is the catch. It almost killed two of us moving the Jet mill. I would have to look around and see what prices are to ship something like that.
If anyone would like to give themselves a treat (people who are machinists at heart) they should go to Windsor, VT and visit the American Precision Museum. It is on the site of a former firearms maker, and has a wealth of info about both general and firearms-related machinery. They have (had at least a few years ago) something called the "5-in-1 machine", I think it's called, which is the only surviving example of a compact machine shop installed on a U.S. WW2 destroyer. Too bad that machine is not highlighted on their website; I saw and learned about it from a retired machinist at the museum. They open to the public on May 25 this year, and here's their link:
I bought, brand-new, a Jet JMD-18 mill almost 15 years ago, and unloaded, moved, and installed it by myself, right next to my 90-year-old Atlas lathe.
The jet 16 almost killed me and my buddy, but then again we are old goats.
Old goat here, too. But all we old goats have much to teach others, eh? That's how we became old.
Totally agree, but with age you realize you still have so much to learn unlike when I was 20 and thought I knew everything.
I have to disagree about the finish produced by the grizzly g4003 and its mill combo brother. Even with a HSS bit, I can get some really nice finishes.
Not saying it's a high quality machine, but better finishes can be had than the worn out south bends I started on. I can guarantee it probably wouldn't last as long though.
We had a huge monarch lathe at tech school that was from a navy ship. Still had USN and an anchor on the ways. That thing was massive! Maybe a 18-20" swing and an 8ft bed. But the headstock was abnormally large and it had a very low rpm range
Monarchs have huge headstocks in general and as such can be tricky to use for some barrel operations as MachIV pictured earlier.
It is quite difficult to find adequately sized vintage lathes with the more desireable shorter headstock that are most suitable for gun work. Probably why everyone is looking for SB Heavy 10s.
That reason alone is probably why import machines are so popular in gunsmithing. That and gunsmithing work (at least modification and repair work) is generally less demanding on equipment than the metal fabrication and machining that goes on in the average manufacturing facility.
Of interest to anyone considering the 7x minis:
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