Thread to Learn Lathe Operations for Swage Die Making

[Cane_man]

would ike to start a thread so myself and others can learn lathe operations specific to making swaging dies, including material selection and all that goes with that topic as well... if the mods allow this here, then anyone please feel free to ask or answer questions so we all can learn... 8-)

first topic: Internal Threading

-is internal threading basically the same as single point external threading?

-what type of tool should be used?

-are the tools with carbide inserts (triangular) preferable?

-what size tool am i looking for to turn internal threads from say 1/4-28 to 5/8-11?

thinking about this type of tool, comments please:

http://www.turning-tools.com/STIR-L-INTERNAL-THREADING-TOOL.jpg

[Cane_man]

'Tubalcain' teaches on single point threading on youtube, this is part 1 of 2 videos:


http://www.youtube.com/watch?v=9y0MmvscBzg


Tubalcain is a retired machine shop teacher, and he always makes it looks easy and explains every detail... highly recommended!

[Cane_man]

here is part 2


http://www.youtube.com/watch?v=5-bTfflIPlc

[bangerjim]

With those very small threads, I always use a tap! In fact anything 1" and smaller I do with taps. So much faster and more accurate to use taps than lathe internal threading tools. I do both RH and LH with taps.

Over 1"......thread chasing/cutting on the lathe is sensible.

I do a LOT of lathe work and threading, both internal and external.

Having operated a lathe for over 35 years, I will be glad to offer advise on your questions. But your small thread question really makes sense to do with taps.

You will probably want to stick to standard American or metric threads, so just buy the taps you need. The only time I lathe cut internal threads smaller than 1" is when I need a "bastard" thread. Since I have a quick-change lathe, I can cut all those weird threads with just the click of a lever. But standard threads are easily done with taps.

Tooling for lathe.......carbide 100%! Except if you have an odd job where you need a special profile ground from HSS blank. I use the special threading inserts, not triangular cutters! Threads are not just a triangle. The one you show above is a threading insert.

Have fun! A lathe is the only tool that can make parts for itself!

banger

[alfloyd]

I agree with bangerjim.
I use a tap or die to cut my threads.
Use the tailstock to keep the tap straight.
I also run the lathe at very slow speed - 78 RPM.

Lafaun

[Cane_man]

use the back gear and slowest speed and feed the tap slowly using the tail stock? not sure how this would work!!!

[Prospector Howard]

Cane, when I've cut internal threads; the lathe basically holds everything staight and I operate everything by hand. The die is in the chuck and the tap is in the tailstock, Then I turn the chuck by hand and turn the tailstock in at the same time. That way you can feel and watch that it's going in right and cutting the threads right. It's probably not the "machinist" way of doing it, but it works for me. Also, I lock two 7/8-14 nuts together on the die so that the chuck clamps down on the nuts and I don't ruin the threads. Someone that sells dies around here had a picture of one of his dies in his lathe with the chuck clamped down on the threads. That doesn't seem like a very good idea to me.

[Red River Rick]

Learning how to "walk" before you can "run" is the first step.

Been doing this for over 30 years...........I know!

RRR

[bangerjim]

If you are talking slooooooooow speeds. make a handle to go in the headstock bore to allow you to turn it by hand with the crank. The thread gears and cross feed are still all powered and you get unbelievable control.

To use a tap in the lathe, start it with the tailstock + chuck until you cannot turn the spindle by hand anymore with the handle. The tailstock is loose and can slide freely yet straight and aligned. Once you get to the "full engaged" threading, use a tap handle to finish it. I do not use ANY power because it is too easy to either have the work spin and gaul in the headstock chuck or you break the tap!

I have full VFD's on my tools and I can get the lathe down to 0.5 RPS at full 1HP, yet prefer the hand crank for threading and tapping.

If you want plans for that handle, PM me.

banger

[Prospector Howard]

Exactly bangerjim, once you get it started good and straight and far enough in; then you can put the handle on the tap and finish cutting the threads all the way in to where you want it.

[customcutter]

I learned the hard way that trying to cut internal threads after you've already cut the external threads will damage the threads. You have to tighten the chuck extremely tight to hold the die, thus "crushing" the threads. I was able to clean them up to usable, but nothing I would "sell" to someone else. When I do internal threading with a tap, I hold the die in the chuck, and the tap in the tailstock, and rotate the chuck by hand while pushing the tailstock in by hand (don't lock the tail stock down). I never could get the "feed" correct trying it with the tailstock locked down and just cut an over size bore.

[Prospector Howard]

That's why I mentioned putting 2 nuts tightened together on the die CC, so you won't ruin the threads.

[bangerjim]

Cane, when I've cut internal threads; the lathe basically holds everything staight and I operate everything by hand. The die is in the chuck and the tap is in the tailstock, Then I turn the chuck by hand and turn the tailstock in at the same time. That way you can feel and watch that it's going in right and cutting the threads right. It's probably not the "machinist" way of doing it, but it works for me. Also, I lock two 7/8-14 nuts together on the die so that the chuck clamps down on the nuts and I don't ruin the threads. Someone that sells dies around here had a picture of one of his dies in his lathe with the chuck clamped down on the threads. That doesn't seem like a very good idea to me.

If I "JUST HAVE TO" clamp on some threads, I use collets. They will do minimum damage to threads in harder materials. I also have a 6 jaw zero-set reversible hard top jaw chuck that will spread the load out among the jaws to do minimum damage to threads. You see guys wrapping stuff in masking tape! Excuse me. tape is a lot softer than the metal and the jaws bite right thru it. "There IS one born every minute." Does not work even on smooth bar stock.

banger

[CastingFool]

Used to run a #3 J & L universal lathe. used collets most of the time, up to 2". Once in a great while, I had to change over to a 4 jaw chuck. Used a die head to do external threads, taps for internal threads. Loved that machine, all manual. Ran a lot of 416ss , 410ss 304, 302, CRS, 1215, & 4140.

[Prospector Howard]

By the way, as far as the "materials" part of this thread. If you've paid attention it looks pretty obvious that these die blanks are being used by someone around here. The 4140 can be heat treated at home if you have a torch, but as it says it's not absolutely necessary. At RC33-35 it'll still last a long time if brass and lead is all that contacts the surface and you keep things clean.
http://www.midwayusa.com/product/444951/ptg-do-it-yourself-die-blank-unpiloted-7-8-14-thread

[Cane_man]

i get it now, thanks!

banger, pm sent

[Cane_man]

i know walk before you can run... i guess i like to try and figure out the more complicated (for me) parts of a project before I get started...

what about coolant and coolant systems?

me thinks this would be very beneficial when reaming out the point forming die... i see guys using spray bottles and here is a system a guy made with a cheap sumbersible pump and a bucket:

http://bedair.org/Grizzly12x/PUMP1.JPG

http://bedair.org/Grizzly12x/Grizzly%20026.jpg

http://bedair.org/Grizzly12x/lathe%20015.jpg

what type of coolant, stream or mist?

[u.p. north]

A good wrap to put around the parts you want to protect is take a pop or beer can and take a utility knife and cut the ends off the can. Be careful thou cutting the can so you don't cut yourself. I wrap the aluminum as may times as it will go around the part. Cut it with the utility knife into strips as deep as your jaws are. Hope this makes sense. U.P. North
Another trick on a lathe is for your dial indicator and magnetic base. Take a 1/4" thick by as wide as your magnetic base piece of flat stock cold rollled steel usually around 2" wide. Cut it about 24" or longer (the flat stock) stick your indicator and base on it and use that on the lathe to indicate things in on the lathe.

[bangerjim]

But that aluminum wrapping causes overlaps....which lead to eccentric chucking. You will have a "valley" where the Al laps over the 1st round and could/would cause errors....at least for me.

I control my tolerances to ~1/2 thou. My zero set chucks (4", 6" and 8") have almost a 0.0003 runout (after much tweaking and twerking!). Sure nice to take a piece in and out and it is ALWAYS dead center!

I just stick my mag base on the tool post holder. Using Aloris tooling, I have room to "grab" a flat spot and lock the mag base down firmly and easily. I use the standard Starrett mag bases and have another one that is only 1" square! Great for tight spots.

banger

[bangerjim]

i know walk before you can run... i guess i like to try and figure out the more complicated (for me) parts of a project before I get started...

what about coolant and coolant systems?

me thinks this would be very beneficial when reaming out the point forming die... i see guys using spray bottles and here is a system a guy made with a cheap sumbersible pump and a bucket:

http://bedair.org/Grizzly12x/PUMP1.JPG

http://bedair.org/Grizzly12x/Grizzly%20026.jpg

http://bedair.org/Grizzly12x/lathe%20015.jpg

what type of coolant, stream or mist?

You are RUNNING! Using coolant pumps is for production and high volume/high speed stuff. I have operated lathes in my home and company shops for many years and all the lube I ever needed was in a squirt bottle. And the pumped systems make a real mess of the lathe, the swarf pan and any associated tooling.

I ream all kinds of stuff all the time and never use a pumped lube/cooling system. Take your time. This is not a marathon race.

But it is your call. I prefer a bottle with a little squirt needle on it.

banger

[u.p. north]

When reaming and tapping it is best to use a regular cutting oil over your flood coolant. On the note of the aluminum wrap cut it to the right length and you will have no overlaps. I have some other tips but most would probably find a way . Alot of home shop machinists don't have six jaw tru_set buck chucks and don't want to spend the money on one. Another note when buying your toolind buy the good american made bars and you will have no problem buying inserts. Buy once cry once when buying your tooling as I speak from experience on that. Although any coolant is bettter than none.

[deltaenterprizes]

Plenty good advice here!

[u.p. north]

On the smaller internal threads yes definitely use the taps, and as said use the tailstock and a drill chuck to get the tap started. Flood coolant works pretty well to lube and flush the cut chips. Also try not to blow air directly on the lathe or mill. Stay 12 inches away or more from the mating surfaces if using air and use low air pressure. Wipe the small swarf off of the surfaces, and add some oil on it when done cleaning. Always keep your leadscrews clean and lubed. Another tip mostly never said make sure to wear your safety glasses, you only have one set of eyes. And practice all other safety first, another words think before you act. Always use a handle on a file.

[smokeywolf]

Cane man, I can tell, bangerjim knows of what he speaks.

The only thing I might add is, unless your machine is very rigid you might be better off using high cobalt content high speed steel toolbits and cutters. If you do use a carbide threading insert, be careful about going too slow. Carbide doesn't react well to very low speeds; too low a speed and it crushes, chips or fractures.

In most cases you will use taps for small dia. internal threads. On the occasion that you do have to single-point an internal thread, I have used a piece of drill rod for a boring bar. Near the end of the bar and at 90 degrees to the long axis of the bar, drill and ream a hole .001 over shank dia. of an old scrapped HS tap. Drill and tap a small hole to intersect the hole for the tap shank. Grind your old tap to your 60 degree included angle for cutting your threads. Insert ground tap through hole in boring bar, lock in place with set screw.

If your boring bar is half inch dia., you can now single point threads in a I.D. as small as 7/8". And, as most machinists have a collection of old dull taps, you have a free supply of cutters for your boring bar.

I have 2 bars made as I described. Tried to find one, but have a bunch of tools boxed up and couldn't lay hands on it.

Here's a pic of an internal single-point tool I ground about 10 or 15 years ago.

97611

smokeywolf

[bangerjim]

smokeywolf........I too make tooling all the time for my metal and wood lathes and milling machines. It is not difficult. I even have a full vacuum heat treat furnace to help with the treating!

(ever dropped a piece on the concrete floor that you just hardened but not yet tempered? Been there....done that!)

I use carbide for everything except the above-mentioned tooling which I make from WH and OH drill rod. If I can buy what I need I generally do, but many times what I need does NOT exist!

Boring bars are a God-send when "making large holes" in stock. I have S&D drills up to 1" and the are great for ruffing out, but boring is dead on center and extremely accurate. Internal threading tools are great for stuff over 1". I do a lot of tubing threading both internal and external to make the scientific instruments I reproduce and repair.

Lots of good info on here.......other than just things that go bang!

banger

[bangerjim]

When reaming and tapping it is best to use a regular cutting oil over your flood coolant. On the note of the aluminum wrap cut it to the right length and you will have no overlaps. I have some other tips but most would probably find a way . Alot of home shop machinists don't have six jaw tru_set buck chucks and don't want to spend the money on one. Another note when buying your toolind buy the good american made bars and you will have no problem buying inserts. Buy once cry once when buying your tooling as I speak from experience on that. Although any coolant is bettter than none.

Tru-set chucks are fairly easy to make from standard ones! I have made 3 of them in the past for my various lathes. All it takes is some planning and knowledge how the commercial ones work internally. Most El Cheapo Chino standard scroll chucks (3, 4, or 6 jaw) can be easily modified to make a really repeatable chuck!

But your soooooooo correct! Commercial tru-sets are very pricey.

Bangerjim

[labradigger1]

Use plenty of oil or cutting fluid when tappping or cutting threads single point. As mentioned above, id smaller than 1" is easier tapped than internal threaded, just not much room for the boring bar in holes smaller than 1".
If using a tap, use the countersink hole in the end of the tap to accept the tailstock center, use a crescent wrench or lathe dog to hold the tap against the carriage.
Remember, go slowly when sp threading and practice on scrap first. Also important is to realize a drilled hole is NOT ROUND, ever. Always drill smaller than final size then use reamers to bring to final size.
As mentioned already tulbalcain has great instructional videos,
an older book called south bends how to run a lathe is also very informative. Practical machinist is another website for endless info on anything machining as cast boolits is to well, cast boolits.
Lab

[smokeywolf]

Part of my apprenticeship involved making bits and bars out of drill rod or Starrett stock; sometimes braising carbide inserts on them. I used to do all the heat treating at MGM Studio Metal Shops. No vacuum on the oven and couldn't do 440 stainless, as the oven couldn't get over 1900* F. Most of the tool steels were O1, W1 or A2. Used a product called Turco Pretreat to reduce decarborization. Also, sometimes used stainless foil.
Had a nice big tank of fish oil for quenching. Might be worth reminding the guys on the forum, when using oil as a quench medium, make sure it has a very high flash point. Also had a nice old Rockwell hardness tester that did C and Brinell.

10 or 12 years ago I bought my first solid carbide boring bar and since then I'm spoiled.

smokeywolf

[sprinkintime]

another way to help you keep your part concentric when you are taking it in and out of the collet or chuck is to put a mark on the collet or chuck and a corresponding one on your part to match, this will insure it goes back in the same place each time. For coolant, I just use a acid brush with what ever I need, such as Cool-Tool, for cutting stainless etc and taping on alum. I use the old fashion way, Kerosene. I still like using Black Oil for cutting large thds. on steel the sulphur in it works. Just my 2cents. Sprink

[bangerjim]

Use plenty of oil or cutting fluid when tappping or cutting threads single point. As mentioned above, id smaller than 1" is easier tapped than internal threaded, just not much room for the boring bar in holes smaller than 1".
If using a tap, use the countersink hole in the end of the tap to accept the tailstock center, use a crescent wrench or lathe dog to hold the tap against the carriage.
Remember, go slowly when sp threading and practice on scrap first. Also important is to realize a drilled hole is NOT ROUND, ever. Always drill smaller than final size then use reamers to bring to final size.
As mentioned already tulbalcain has great instructional videos,
an older book called south bends how to run a lathe is also very informative. Practical machinist is another website for endless info on anything machining as cast boolits is to well, cast boolits.
Lab

If you want your threaded hole to be dead on size and concentric, reamers will not do the trick. I always use a boring bar for the final few thou to true up the hole. I have micro bring bars that I can get inside a 3/8" hole. May not be critical for what you are making but the stuff I make needs the hole/threads to be EXACTLY in the center!

banger

[bangerjim]

another way to help you keep your part concentric when you are taking it in and out of the collet or chuck is to put a mark on the collet or chuck and a corresponding one on your part to match, this will insure it goes back in the same place each time. For coolant, I just use a acid brush with what ever I need, such as Cool-Tool, for cutting stainless etc and taping on alum. I use the old fashion way, Kerosene. I still like using Black Oil for cutting large thds. on steel the sulphur in it works. Just my 2cents. Sprink

Good point on the witness mark. I keep a Sharpie handy all the time and do just that. Only problem is if guys have cheap or old warn chucks, there is enough slop in the jaw channels and scroll threads you can end up with 0.003 or more slop when retightening. Collets should pretty much dead on if your stock is round!!!! Very important! I keep a dial indicator (lastword) mounted on my apron for checking.

banger

[labradigger1]

If you want your threaded hole to be dead on size and concentric, reamers will not do the trick. I always use a boring bar for the final few thou to true up the hole. I have micro bring bars that I can get inside a 3/8" hole. May not be critical for what you are making but the stuff I make needs the hole/threads to be EXACTLY in the center!

banger
I was'nt referring to reaming the hole before tapping, i was referring to holes in general, the op wanted a thread to help w/ learning sizing dies, a drilled hole is never round and not everyone has lettered sts of twist drills.
lab

[smokeywolf]

I used to, if I was in a hurry, in the lathe I would drill, then bore 20 or 30% of the way in/thru and a couple thou under finish size, then ream to finish. That first little bit that I had bored would act like a bushing for the reamer. The scenario that prompted this was usually a high speed film developer down that was costing the company $1,000.00 dollars per minute. The mechanic would be standing there waiting for the part.

smokeywolf

[Cane_man]

KNURLING

from what i read yesterday what is important is the pitch of your knurls, and the diameter of the piece your are working on... the goal is to make sure the diameter of the work is correct so that there are an even number of teeth marks on your work (which prevents overlappings knurl marks)...

n = knurl pitch = given in TPI, teeth per inch (should be marked on the side of the knurls), if not you need to count how many teeth are on the knurl and divide that by the circumference of the knurl, circumference = diameter x 3.1416

d = diameter of the bar your are knurling

number of teeth marks = n x d x 3.1416, the number of teeth marks to be an even number to prevent overlaps...


example: using 20 tpi knurls on 1/2" round bar

teeth marks = 20 x 0.5 x 3.1416 = 31.416

because the teeth marks is not a whole number there will be overlapping knurl marks, so to get it perfect round down the teeth marks number, so in this case 31.416 would be rounded down to 31, now solve for the diameter:

d = (teeth marks) / (tpi x 3.1416) = 31 / (20 x 3.1416) = 0.493

this means that the 0.5 bar needs to be turned down to 0.493 to get even teeth marks with no overlaps


you guys that have actually done this before is this method going to work?

[screamingjohnny]

Thanks for all the good info on this thread.

[bangerjim]

KNURLING

from what i read yesterday what is important is the pitch of your knurls, and the diameter of the piece your are working on... the goal is to make sure the diameter of the work is correct so that there are an even number of teeth marks on your work (which prevents overlappings knurl marks)...

n = knurl pitch = given in TPI, teeth per inch (should be marked on the side of the knurls), if not you need to count how many teeth are on the knurl and divide that by the circumference of the knurl, circumference = diameter x 3.1416

d = diameter of the bar your are knurling

number of teeth marks = n x d x 3.1416, the number of teeth marks to be an even number to prevent overlaps...


example: using 20 tpi knurls on 1/2" round bar

teeth marks = 20 x 0.5 x 3.1416 = 31.416

because the teeth marks is not a whole number there will be overlapping knurl marks, so to get it perfect round down the teeth marks number, so in this case 31.416 would be rounded down to 31, now solve for the diameter:

d = (teeth marks) / (tpi x 3.1416) = 31 / (20 x 3.1416) = 0.493

this means that the 0.5 bar needs to be turned down to 0.493 to get even teeth marks with no overlaps


you guys that have actually done this before is this method going to work?

That is a textbook world. This is the real world.................

You cannot figure knurling as cutting teeth. You pick your pattern fine coarse, medium, straight, diamonds, rope, etc) and just do it.

I never worry about the size of the piece. That is something that is not under my control. If a piece is .4568 or .39999 or .5145 then it gets knurled...same set of rolls for pattern I want! You are VERY limited by the number of rolls you can have, unlike a tap & die set.

When knurling, do NOT use one of those single point *** tools. Get the 2 roll scissor tools that applies pressure from the top and bottom. It's shank fits in your tool post. I use quick-change tooling. That way, it does not stress your cross feed parts because the process takes a ton of pressure...literally! I have 3 sizes of them for small to VERY large stock. And you can easily change the knurl rollers out...just knock out the pins and change them. I have 8 different sets of rollers.

I also use a hand knurling tool which has 3 rolls in it. You can use in the lathe or away from the lathe in the bench vice! Nice.


And it's not just a "perrrrrty face"!


Knurling is the only machine tool process that can ADD diameter to a piece! I use it quite often to expand diameter so a piece will be a good tight press fit in the arbor or hydraulic press. And if you mess up, you can make a tight fit from a under size screw-up. (don't ask how I know!)

banger

[Cane_man]

^^^ thanks Jim, I do have that scissors type knurling tool just did not really know how to use it... i have 3 sets of knurls, one is 20 tpi...


what do you guys think about grinding your own tool bits from HSS, like this:

http://varmintal.com/toolbits.jpg

how do you do this on a bench grinder?

[Swede44mag]

^^^ thanks Jim, I do have that scissors type knurling tool just did not really know how to use it... i have 3 sets of knurls, one is 20 tpi...


what do you guys think about grinding your own tool bits from HSS, like this:

http://varmintal.com/toolbits.jpg

how do you do this on a bench grinder?

Looks a lot like the bits we learned to grind in Machine Shop Class at VOTEC

[bangerjim]

I only grind tools from HSS when I cannot find one of the shape I need in carbide! I was lucky several years ago to run across a 5 gallon bucket (guess how many # of carbide there are in a bucket!!!! OMG) of carbide inserts that mostly were un-used. Every shape and kind you can find in the tool catalogs. Most are TIN.

What I do make are all the holders for the inserts. Make them from WH square bar stock.

To grind HSS tools, I made an indexable little holder to hold on the grinder tool rest so I can repeat the angle I am grinding over and over. Once set, you can grind and quench, always returning to the same preset angle.

I used the exact HSS tools you show for many years when I first started out. They work well for general metals. Just keep a little diamond hone (600) handy to touch them up occasionally. That allows you to go for a long time without regrinding to sharpen!

And a low speed grinder is the best (1750 RPM). Better control and much less burning. HF sells a slow speed grinder for a decent price. But it is HF! What you hate is blue tips on your bit!!!!!!! Use a good stone. I use medium grit. Fine will burn to easy. Green is for carbide. Have a grinding wheel dresser handy.......and use it regularly! A flat and square face is an absolute necessity. Either a diamond point or multi tooth metal dresser works well. And do not use that stone to sharpen other tools or lawnmower blades!!!!!!!

banger

[smokeywolf]

banger, knurling because you screwed up and went under size is cheating... Done it myself a number of times.

My first 20 years of machining was without insert tooling. Used brazed carbide, HS, cobalt, tantalum tungsten and stellite tooling.

I always try to use a guide or fixture for regrinding. But, that not always being practical or prudent, I became pretty good at off-hand grinding.

smokeywolf

[Cane_man]

http://www.davehylands.com/Machinist/Charts/Toolbit-Grinding.jpg

http://www.chaski.org/homemachinist/download/file.php?id=16537

[bangerjim]

Many of us today do not have the old rocker style tool posts and forged holder that fit in them. Everybody has gone to Aloris style quick-change holders that are parallel to the bed. The old school way had relief angles and such to allow chips to curl off properly. Today, that is built into the carbide inserts.

The old "lantern style" tool post is what I grew up with but now am glad I DON"T have to spend all that time getting the cutter on center each time I change cutters by rocking the tool back & forth!!!!!!!! I still have a full (RH & LH) set of those old Armstrong-style tools including cut-off, single point rocker knurling, etc. On rare occasions they come in handy, but spend most of their time "resting" in the cabinet!

Grinding HSS lathe cutter blanks to the correct shape is very time consuming. That stuff (the GOOD stuff) gives off hardly any sparks....more like little dull red balls.....is VERY hard, and takes forever to form the shapes (without them turning blue). HSS can take a lot of over-heating, fortunately. Once you are there.....pant, pant!.........you can keep them sharp with a diamond hone as I mentioned above, going back to the grinding stone rarely.

Now let's go make some chips!!!!!!!!!!!!

bangerjim

[smokeywolf]

Used almost nothing but KDK tool posts and holders for 25 years. Used an old rocker post only 3 or 4 times. About 8 years ago, got hold of a brand new Dorian Quadra Indexing post plus 4 used and 2 new holders for under $500. Sold my KDK plus 7 or 8 holders for double what I paid for the Dorian post.
Compared to the KDK, the Dorian post is a monster (CA size). But, set up right, I can turn, face, knurl, profile and part off without swapping a tool holder.

I've spent a lot of hours in front of pedestal and surface grinders, grinding HSS form tools. Retired chasers from geometric die heads make great form tools.

smokeywolf