Mini-Lathe to trim copper tubes-jacket

[shoebox56]

I'm using copper tubing to make jackets. Would like to use a Harbor Frieght mini lathe to trim the tubes to same length. Following some posts, some have used collet and end mill on their lathe. Can someone point me to where I can buy the collet and end mill? So far, collets I've seen online doesn't to seem have any way to control the depth of tube insertion. I'm not sure, really have zero experience with lathes.

Thanks.

[AndyA]

You can buy a soft collet and bore it to diameter and depth. This leaves a shoulder at the bottom for the tubing to sit against.

If you have a chuck, you can use soft jaws and get the same result.

[IllinoisCoyoteHunter]

There are several options for you. You can use a 5c collet chuck on your lathe. You can use a stop with 5c collets to control the length of your tube. I would check with Shars. They sell cheap stuff that works fine for the average hobbyist. Also look at cdcotools.com. They have cheap tooling too. I would look into a collet chuck and a thin parting tool. Then maybe a tool to debur or chamfer the tube.

[country gent]

Im not sure what collets the harbor freight mini lathes use but 5c would be way to big. I would look at some of the smaller D series collets and chucks. you can bore the collet to fit by shimming the slots solid so the collet cant collapse then bore to size leaving a shoulder inside. 5 C soft collets have a 1/8" pin in the slots to bore then the pins are removed.

What might work as well and cheaper is a wilson style case trimmer With a split bushing for.the holder and used in a drill press.

On a lathe I would use a good chuck or collet and a tool bit to face it, on my lathes maybe even on the harbor freight minis you could put a length thru the head stock, use the tail stock with a stop and a cut off blade to part them off to length. Just measured my central machinery mini ( bought at harbor freight) its spindle bore is around 3/4"
I would make the stop with a smaller pin . This and a slotted spacer. the pin will catch the piece, the slotted spacer inserted to set the length then removed so the part dosnt catch and bind. This set up would cut to length with out measuring each piece after it is set up.

[Scrounge]

There are several options for you. You can use a 5c collet chuck on your lathe. You can use a stop with 5c collets to control the length of your tube. I would check with Shars. They sell cheap stuff that works fine for the average hobbyist. Also look at cdcotools.com. They have cheap tooling too. I would look into a collet chuck and a thin parting tool. Then maybe a tool to debur or chamfer the tube.

You might want to notice that he's talking about using a mini-lathe. 5C collets will not work with it. ER32 are a better size for the mini-lathe. ER40 are workable for smaller size materiel, but the bore is only about 19mm/3/4". You could also get MT3 Collets, which will fit the taper in the mini-lathe spindle, or MT2 collets and a MT2/MT3 sleeve to get them to fit. Little Machine Shop, littlemachineshop.com, is a good source for import tooling, and info on the mini-lathes. One of the advantages of the mini-lathes is that they're relatively cheap to buy and tool up. One of the disadvantages is that they are not necessarily as accurate as a US-made lathe. They're not necessarily bad, either. Older mini-lathes were more variable in that respect, new mini-lathes are a lot more consistently decent.

Otherwise, the tool sources you mention are good, but they don't have a lot of stuff specifically for the mini-lathes. If you're buying Morse Taper 2 or 3 (MT2 or MT3) tooling, you can get them at CDCO Tools, or Shars. Also Amazon.com & eBay. Decent measuring tools, V-blocks, and several kinds of collets, among many other things.

Bill

[IllinoisCoyoteHunter]

So, a couple things I will point out. Most mini lathes are 7” x 10” or 12” or 14”. That means they can swing, theoretically, 7” diameter stock. We all know this. You can get a 4” or 5” 5c collet chucks from several different places online. Will you have to make an adapter plate? Maybe. If you buck up and extra $100 and go with a Grizzly instead of the harbor freight, which I would do, you will have no problems running a 5c collet chuck. There’s videos on YouTube showing how to do it. Plus, if you have to make your own adapter plate, it wouldn’t be hard and could be done as a project. Not to mention a 5c collet chuck is a very handy chuck to have, especially for making small parts you’d make on such lathe.

https://m.youtube.com/watch?v=qbXj2BcXGpQ&t=43s

https://m.youtube.com/watch?v=zHDa707aEBQ&t=25s

[Scrounge]

So, a couple things I will point out. Most mini lathes are 7” x 10” or 12” or 14”. That means they can swing, theoretically, 7” diameter stock. We all know this. You can get a 4” or 5” 5c collet chucks from several different places online. Will you have to make an adapter plate? Maybe. If you buck up and extra $100 and go with a Grizzly instead of the harbor freight, which I would do, you will have no problems running a 5c collet chuck. There’s videos on YouTube showing how to do it. Plus, if you have to make your own adapter plate, it wouldn’t be hard and could be done as a project. Not to mention a 5c collet chuck is a very handy chuck to have, especially for making small parts you’d make on such lathe.

https://m.youtube.com/watch?v=qbXj2BcXGpQ&t=43s

https://m.youtube.com/watch?v=zHDa707aEBQ&t=25s

Even on the 14" Mini-lathes, you're going to eat about 4-5 inches of your bed length with a 5C collet chuck. They will not fit in the the bore of the spindle. It's a Morse Taper #3, and about 0.938" ID at the opening. A 5C collet is 3.27" long, & the spindle end is threaded 1.238"-20tpi. The nose of a 5C collet is 1.48" across. You're going to need a backing plate to keep the collet away from the spindle, plus the length of the collet chuck itself. If you get the mini-lathe from HF, your choices are 10" & 12". LMS, Grizzly, and Micromark (and maybe some others) sell some 14 & 16" bed mini-lathes.

If you already have a bunch of 5C collets, it's probably worth doing. If not, probably not!

If you're starting from scratch, this or something like it is a better choice: https://littlemachineshop.com/produc...ory=-421559299 it's an ER-32 chuck, and it's shorter than the stock 3-jaw chuck. I now have something very similar on my Atlas TH42, which is essentially an American-made mini-lathe. MT3 spindle taper, MT2 tailstock taper, but a 24" bed, and 10" diameter.

Before I got initiated into the usefulness of collets, I got a 5" 4-jaw chuck for my 7x10. Used it, liked it, but it used a significant portion of my 10" bed. If I live long enough, I've got a South Bend Heavy 10L under restoration, when and as I can work on it. It came with two 5C collet closers, and a whole two 5C collets...

Bill

[shoebox56]

Thanks everyone, this is a lot of information!

"If you're starting from scratch.." Yes, I am starting from Zero and a fresh mini-lathe. I have zero experience in machining, but willing to learn. I'm reading everything and researching it what's been mentioned so far.

[country gent]

The base dia on my south bend collet chuck is around 7" and its almost 6" long. The mounting thread is 1 1/2 8. I use it on my rotary table in the mill. The weight of the chuck would put a lot of strain on bearings and brake of the mini. A better choice would be a DA or other of the smaller collets. The added length would also put added strain in the bearings working unsupported.

He could take a piece of aluminum 1 1/2" turn a 1" round stem the length of the jaws with a flange to set against the jaws. drill it close to size split one side thru and halfway thru the other side put in chuck bore to size with the step and use the chuck. As long as its bored in the chuck and not removed there is very little run out.

Going by my machine here the chuck is bolted on with a 3 hole pattern and is a 3" chuck and flange, not threaded. turning and machining 3' while with in it size limitsis goingto be fun with the power limitations. Mine wont power tap a 3/8 24 thread it stalls out. I use it mostly for polishing, occasional very small parts that are hard to get in the 2 bigger machines easily IE the 14 x 40s chucks only close down to around 3/8" ( both the 3 jaw and 4 jaw).the 12 x 40 has 5c collets down to 1/16" but spindle speed is at most 970 rpm to slow for good work on the really small stuff.
Thats why I suggested what I did. turning the adapter custom chuck is going to be several steps turn for flange and mount ring if there is one, here will be the reversed jaws with very little grip Then drill the three holes and mount to machine. Then turn to true to the spindle. the bore then needs to be bored to a precise angle and size. Then the thread cut. A da collet chucks stem can be cut down in length to fit in the chuck and comes with collets. Look for them at shars, penn tool, mini/little machine shop,McMaster Carr.Much lighter and more compact than the 5c set ups.

[IllinoisCoyoteHunter]

I’m not going to get into an argument about useable bed length, power, or whether a backer plate is needed. As the op stated he wants to use it down simply trimming copper tube, which doesn’t need much bed length or power. I’ve done what the op wants with a benchtop Grizzly lathe and home made ER40 collet chuck. A few thoughts on using ER collets. The ER32 collet chuck in the link provided is not a bad choice but the op is going to need a stop to keep his jacket length consistent. In the past I’ve looked for emergency ER collets and my search basically turned up nothing. So boring an ER collet with a shoulder as a stop won’t be an option. The same ER chuck could be used if you could rig up a stop that bolted to then back of the machine and ran through the spindle. What I ended up doing was fabricating a collet chuck and making a stop that would fit inside it. Here is a link to one of my videos trimming cartridge brass I was using as jackets.

https://m.youtube.com/watch?v=JYgNcdqi4ew&t=103s

So, if you can rig up a stop, an ER collet chuck is definitely the way to go. 5c collets are plentiful and you can find a multitude of emergency collets you could bore for your specific applications to eliminate your need for a part stop. The ER chuck would be faster but the difficulty of figuring out how to use a stop is really the hold up.

My last piece of advice for the op. Buy the biggest lathe you can afford and have space for. If you are into swaging there is no doubt you will want to start making your own equipment. As others have stated, these mini lathes have some limitations on power and rigidity. Bigger machines allow for faster production. Am I talking about spending $3k on a lathe? No. But I’ve never heard anyone say they wish they had a smaller lathe lol. If you buy a slightly larger lathe I think you will be much happier and it really opens up more doors to enjoy your swaging, reloading, and new found machining hobby. Lol

[Jimmynostars]

Straight shank collet holder and rig up a stop for it, hold it in a 3 jaw work out your length and nip up the saddle.

Make some soft jaws out of 1045 with a shoulder in the back of them as a stop.

2quick ideas

[IllinoisCoyoteHunter]

Straight shank collet in the 3 jaw is a great idea. If it’s got a through hole, which most do, a nut could be tack welded on the back and threaded rod could be used as a stop. Or weld a small small round plate over the back and drill and tap a hole for the small diameter threaded rod.

[country gent]

A piece of shim smaller than the split in a er collet cut to width and shape in the 2 opposing grooves makes a stop for the er collets once insert in the holder its captive.
The big plus to the double angle collets is they close evenly unlike a 5c or r8. the bore in a er collet is straight and they have a greater range than others for this reason.

If the OP wants to go with the er collets he can send one to me and I will open it up for the stop ring in side or make the shim stop for free. I have an er 32 holder with a straight shank I use in my end mill sharpener that I can put in the lathe to rework it.

[IllinoisCoyoteHunter]

I agree about the parallel clamping force on the ER collets. Much better gripping force vs the 5c. But again we are talking about trimming copper tube. We aren’t making a .100 DOC in 718 Inconel. A small lathe can do this job, but I’d strongly urge the OP to go with a bigger lathe if funds permit.

[country gent]

I see nothing wrong with the mini lathe with the correct set up for this job.If the stock will pass thru the head stock and the straight shank er chuck I feel the stop I described for the tail stock would work best and save cutting the pieces close to length. Cut a 2' length and use a 1/16" parting tool. cut the first edge to square it then just push thru to stop and cut off the rings to length. A live center could be used for the stop but there is no room there and a piece may wedge breaking the tool.

Actually I think for a dedicated machine for this job the mini lathe is ideal. Its probably not going to be an "every day" task and when not in use it can be stored on a shelf out of the way set up and ready to go. A Hss steel cut off tool ground on a 5/16" square blank will give good service and be easy to resharpen. and on a 5/16 x 2 1/2' lomg blank give many resharpenings At around $6.00 a piece 2 should last a lifetime. Here I think a mini would shine A little dish soap for cutting lube Ill be he gets nice shiny ends with no galling , feed marks or heavy burrs,
While copper isnt a hard material it has it own issues machining galling and finish are 2 and the tubing crushes easily in a chuck or collet. The cut off blade with a little soap will give nice rolled chip thats very controllable, The thin bade fed straight in will need little pressure. and only 1/16" lost to the cut. over the years this will gain him some "free" bushings over the cut and face.

[rbuck351]

Turn a piece of round stock to a size that fits your jacket tubing with a slightly shorter turned pin than the length of your jacket tube. Insert this in your tailstock chuck with the pin out. Insert you jacket tube through the head stock onto the pin and set your cut off tool for the desired length of the jacket and part it off.
The pin with the shoulder and the part off tool set and locked will control the length of the jacket. Cut one piece, loosen head stock chuck, remove jacket tube, slide jacket stock on pin, tighten chuck and cut off another jacket and repeat. No need to buy more tools for your mini lathe.

[shoebox56]

What might work as well and cheaper is a wilson style case trimmer With a split bushing for.the holder and used in a drill press.

Country Gent: Although I still want to go the mini-lathe route, can you elaborate some more on the wilson style trimmer? Is that the L.E. Wilson Case Trimmer? Particularly where to get that split bushing and how to set it up. Not clear how that works. Thanks.

[Jimmynostars]

Kerosene for cutting I think, if you feed in a length or 3 feet of tube I feel the rpm for parting will cause it to whip and then bend. A mini drop saw to cut a little over length I think would be best.

Bear with my metric mind, if you had a straight shank collet holder and a soft collet.

For arguments same you want an 8mm holder with a 6mm shoulder for a stop.
You could possibly put the blank in and do the collet up tight, drill straight through with a 5.5 drill.
Cut the shank the drill put it in the collet behind where you want the shoulder and do it up.
Put an 8mm cutter in your tailstock and plunge until you have enough depth for your brass tube.

Also you could get a silica bronze rod and tig a nut to the back of the shank for a stop as above (country gent)

[country gent]

Yes I was thinking the L E Wilson case trimmer, Instead of the shell holder a holder would need to be made. A piece of round stock the same OD as the shell holders drill a hole thru smaller than the tubing's dia. then bore to tubing dia. Split completely thru one side and half way thru the other ( this allows it to clamp much easier with the original clamp) you use the existing stop against the back of the holder. Here depending on your cut the first side cut to stop .020 long then flipped and a .020 shim between stop and holder to finish.

You can make a er holder for the drill press to do the same thing. This would be a lot more work and then depend on the drill press stop to hold length, most arnt as good as the Wilsons

[Willbird]

Here is another idea. Turn up a soft collet to fit into the 3 jaw chuck. Leave a head on it so that it stops against the front of the chuck jaws. You might maybe want it only 1/4" bigger than the tubing dia where the chuck jaws grab it.

Rough machine the ID, maybe 1/8" smaller than the tubing. Take the collet out and split it 3 times right up to the head. Then put it back in, I would mark it to match one chuck jaw. snug the chuck but do not go crazy tightening. Then single point bore a counterbore with a stop for the tubing.

Should let you grip the tubing and face off the end square and to length.

Probably with an index mark it can come in and out and still run fairly true.

No $$ cost involved, only your time as long as you can find some oddball material, I'd use Aluminum as long as I could find it.