[MechanoMan]

Well, after waiting for a deal to show up...
Local shop guy puts up a Sherline 4400 on Craigslist for $500. That's the LONG one. He'd moved on to bigger metalworking lathes and needed the shop space cleared.

And it just kept getting better. He had the CNC leadscrew and NEMA23 mounts. Threw in a stepper then dug in a bin and pulled out another new stepper! And there's tons of other miscellaneous parts I have no clue on. I recognized a steadyrest. I've never used a lathe. And it's all mounted on a neat case-box.

Didn't have chucks but I have a Sherline Rotary Table on my Taig and already have the 3-jaw self-centering and 4-jaw independent here. No problem!

Oh yes yes I have the lathe, it's here in my hands!

Now one of my first things, I need an 8" long 0.8" OD (plus a 1" flange, so I need to machine the outside) UHMW tube with a 5/8" ID. So I'm gonna bore out 1" UHMW rod stock. Now do I start by drilling a pilot hole and bore it out to diameter, or should I just use a large drill bit in one shot? I think I even have a good long auger of this size, but would that be a bad idea due to the self-feeding nature of the auger trying to suck its way into the plastic?

Will the drill bit ensure the hole is centered, so it maintains a fixed wall thickness when the outside is machined down? See, I know a second bore operation should definitely be centered.

[Teyber12]

i am a lathe noob and never seen a sherline-

but because nobody else responded... In plastic just drill a hole big enough to fit the boring bar in there, then just use a boring bar till your at the right size

congrats on the purchase!

[blades]

Pics man, PICS! Congrats on the purchase!

[MechanoMan]

I don't have a boring head though. Plus a boring bar can't go really deep, right? I need a hole like 6" deep on at least one of the 2 things I need to do right now. Which, I can see where I could bore out a guide hole for the drill bit, and boring is more accurate than ram-drilling it, but the drilling is probably more than accurate enough.

Actually how does tailstock drilling even work?? The tailstock is fixed, and the leadscrew does not move it. Do I just move the tailstock to the other side of the crossslide and let the crossslide push it?? The crossslide won't be able to withdraw it from the drill bore.

Actually I'm kind of annoyed to realize that a) the nice, expensive 4-jaw indy and 3-jaw SC chucks I have for the Sherline rotary table will not work on the Sherline lathe. At least not without riser blocks. Once the jaws are opened at all, the outer bits will strike the bed.

Plus the tailstock... what's with this MT0 crap? I found I need a bullnose live center and MT0 jacobs chuck, probably a boring head, and realized that MT0 stuff is kinda rare and I can't get anything locally, and I'm gonna have to pay through the nose. Basically double or triple what normal MT2 or so stuff costs. I mean HFT I could get a MT2 bullnose for $25, jacob's chuck is $7. Sherline's MT0 bullnose is like $75.

Really I need some of that either way to use with the Sherline tailstock for the Taig mill fitted with the rotary table, even without the lathe tool, but the MT0 size is a huge liability.

Well, I got it all set up for CNC now. I mean it was a good deal with the CNC kit and all, and it's got an impressive 17" between centers which may be necessary at some point.

[acondit]

Look up some of the Taig stuff. It used to (many years ago) be much better priced than the Sherline stuff. You can't use everything Taig on the Sherline but probably the centers.

Alan

[blades]

Actually how does tailstock drilling even work?? The tailstock is fixed, and the leadscrew does not move it. Do I just move the tailstock to the other side of the crossslide and let the crossslide push it?? The crossslide won't be able to withdraw it from the drill bore.

Your tailstock should have essentially a spindle or quill built into it that you crank out, much like a drillpress, except the chuck will be stationary (not spinning). Is this assembly missing on your tailstock?

Does your tailstock look like this one?

[ZipSnipe]

Hey Mech, I would definitely drill what your trying to do. Now hopefully your drill chuck will hold a big enough drill bit to do what you want. To drill simple retract the drill chuck as far back into the tailstock, then move your tailstock up to your piece, lock your tailstock down and start drilling, when you extended the chuck as far as it goes retract the chuck and slide your tailstock in a little more and repeat process. Don't forget coolant of some type(wd 40 works).
But honestly it sounds like ya need a bigger lathe for what you want to do or for the size drill bit you need you,ll probably need to grind the end of it so it can fit in your chuck.

Good Luck!!

[MechanoMan]

I do have that tailstock. However, the depth of the motion with just the tailstock crank is very shallow, and I don't see how it'll do the job.

I've got the 17" between-centers lathe. I was looking to bore out say a 1" dia, 6" long piece of Delrin with a 1/2" hole 6" deep. So the plan was to first dig a center with a center drill mounted in the non-turning tailstock chuck, then chuck a >6" long drill bit on the tailstock chuck, use the CNC leadscrew to drive it in 1/2", pull it out to clear the debris, and peck again in cycles.

But there's no way to drive the tailstock chuck in like I'd thought. So I seem to be looking at just drilling/boring like a 1/2" starter hole with the lathe, then trying to use it as a guide hole to finish the drilling with... I guess a hand drill, in which case I've no idea how to hold the rod and keep it from spinning either.

Or unlock the tailstock gib and manually push it down the bed slide?

Isn't there a way to mount a drillbit on the crossslide table so the leadscrew can drive it in? All I could think of was unlocking the tailstock gib and somehow tying the tailstock to the crossslide so the leadscrew will take it in and out.

[Hans_G]

I would look at McMaster for UHMW or Delrin tubing with the correct ID and then turn the OD to whatever you need. A 6" or 8" long piece in those chucks won't be held securely at all- the length of the jaws is just too short, and the bore through the chuck is too small (.68") to clamp the piece in the middle.

I bought a Sherline 4400 about 3 years ago. I bought a Grizzly G0602 3 months ago. I love the G0602. The Sherline? Well, it's destined for ebay.

[blades]

Isn't there a way to mount a drillbit on the crossslide table so the leadscrew can drive it in?

That's a question only you can answer.
You can do anything you can imagine, but how well it can be done is the real trick. All depends on your creative genius and what you have on hand that you can make do with. What you describe is definately doable though, but with somewhat light drilling pressure since it wouldn't be as stout of a setup as the tailstock would be.

[warossignol]

Use a one undersized drill bit and then come back thru with a reamer of the proper size. Use Air or coolant as you ream and go slow. you don't want to melt the delrin back into itself.

[wwendorf]

You drill to the depth of your quill in your tailstock, then you stop the lathe, retract the quill, unlock the tailstock, move it forward into the hole, lock the tailstock down, then turn on the lathe and drill to the depth of the quill in the tailstock again.

Repeat till you are at the necessary depth. If you try and move the tailstock with the crossslide, you will have a very inaccurate and wobbly hole.

Wade

[kweierbach]

I'd put that mill to work and make a block to mount on the cross slide with a hole the size of the shank on your drill's that is on centerline with the chuck to hold your drills and use the z axis feed to drill the hole.

[MechanoMan]

I'd put that mill to work and make a block to mount on the cross slide with a hole the size of the shank on your drill's that is on centerline with the chuck to hold your drills and use the z axis feed to drill the hole.

Well that's certainly a top idea there.

My concern with that would be in keeping the bit's axis totally parallel with the bed and ensuring that the crossslide position has it pointing straight down the rotational axis. Probably not insurmountable problems, there will need to be some careful setup procedures though. Bolting 4 T-nuts into the crossslide rails does not provide a high degree of rotational accuracy, maybe I'd make a mount with tight-fitting rails sticking out underneath it to position it accurately on the crossslide.

I'm just surprised I seem to be the first person to want to bore a deep hole automatically? I didn't see any tailstock-crossslide mounting hardware or instructions on this operation.

[Teyber12]

With my x3 i often just bore a hole with nothing there before with a boring bar in polyethylene, gotta take it slow then slowly work to the ID i need. If your machine seems up to the task doesn't hurt to try but it makes a ton of racket and is scary on the x3, can't imagine it on a sherline lol

[kweierbach]

Well that's certainly a top idea there.

My concern with that would be in keeping the bit's axis totally parallel with the bed and ensuring that the crossslide position has it pointing straight down the rotational axis. Probably not insurmountable problems, there will need to be some careful setup procedures though. Bolting 4 T-nuts into the crossslide rails does not provide a high degree of rotational accuracy, maybe I'd make a mount with tight-fitting rails sticking out underneath it to position it accurately on the crossslide.

I'm just surprised I seem to be the first person to want to bore a deep hole automatically? I didn't see any tailstock-crossslide mounting hardware or instructions on this operation.

Turning the O.D. maybe more of problem. what kind of turning tool did you get with this lathe. you may get chatter when turning that thin of a wall if you don't have postive rake turning tool.You may want to turn it first using the center for support then drill it and hope that the steady rest doesn't mark it up to much.Or drill it first and if the center is to small you will have to make an end plate and tighten the against it for support.

[Thayer]

I don't have a lot of experience in this regard, but what about just mounting a block on the cross slide and drilling it on the lathe? If you don't move the cross slide, you could then reverse the bit, secure it in the block (slotted with a clamping screw?) and drill away?

Thayer

Well that's certainly a top idea there.

My concern with that would be in keeping the bit's axis totally parallel with the bed and ensuring that the crossslide position has it pointing straight down the rotational axis. Probably not insurmountable problems, there will need to be some careful setup procedures though. Bolting 4 T-nuts into the cross slide rails does not provide a high degree of rotational accuracy, maybe I'd make a mount with tight-fitting rails sticking out underneath it to position it accurately on the crossslide.

I'm just surprised I seem to be the first person to want to bore a deep hole automatically? I didn't see any tailstock-crossslide mounting hardware or instructions on this operation.

[imserv]

Well that's certainly a top idea there.

My concern with that would be in keeping the bit's axis totally parallel with the bed and ensuring that the crossslide position has it pointing straight down the rotational axis.

You can use the Z-axis ( Saddle) for drilling, if you mount a 3/8 shank drill in a 3/8 boring bar holder with a Quick Change tool holder.

You will have to indicate the QC post in, and will probably want to use a piece of 3/8 drill rod or Dowel to check the axial alignment of the 3/8 tool holder. Mount a mag base indicator to the chuck, and rotate the chuck to indicate the rod into the center of rotation and also use the same setup to check along the length of the drill that the center of the drill is on center with the spindle. Check both top and side for alignment.

Fred Smith - IMService
http://www.imsrv.com

[MechanoMan]

I was able to accomplish the basics of what I needed by center drilling, then changing to the chucked twist drill and using the short thrust stroke of the tailstock screw, then just loosening the tailstock-to-rail screw and hand-ramming it into the Delrin, pulling out to clear, and repeating.

The trouble I have now is parting. I have the 3.25" dia 4-jaw indy chuck (but it's not the official "Sherline lathe" 3.1"):

The problem here is that the only orientation which doesn't strike the bed is the jaws with the steps on the inside. This does not provide enough grip to stabilize the Delrin without a tailstock, not in this length. Tightening further only makes the Delrin pop out.

The problem in the parting is that you can't use a tailstock. Well, I tried anyways with the tailstock pressure minimal. Eh, the results didn't put me in fear of my life or anything. But even though the parting tool went in at 90 deg to the work, the tip walked WAY off to the right, leaving the left side concave and the right side convex when all was done. This happened irrespective of how fast it was driven in.

Why did the parting tool's tip walk so much? I see Sherline recommended a 5 deg angle on the blade when viewed from the top. I'm not sure I see why, that would seem to make it cut unevenly to me. I can't tell for sure what angle my blade does or does not have.

I kinda wanna just hold a hacksaw over it now and drop it down to cut it...

I found that with.... I guess it's about 3" long part with a 3/4" new diameter- the end face couldn't be finished either because again the jaws can't hold that stable without a tailstock, but the SteadyRest will probably cure that. In fact I might be able to use the SteadyRest instead of the tailstock for the parting operating, right? Still won't fix the real problem of the parting tool wandering though.

[kweierbach]

I was able to accomplish the basics of what I needed by center drilling, then changing to the chucked twist drill and using the short thrust stroke of the tailstock screw, then just loosening the tailstock-to-rail screw and hand-ramming it into the Delrin, pulling out to clear, and repeating.

The trouble I have now is parting. I have the 3.25" dia 4-jaw indy chuck (but it's not the official "Sherline lathe" 3.1"):

The problem here is that the only orientation which doesn't strike the bed is the jaws with the steps on the inside. This does not provide enough grip to stabilize the Delrin without a tailstock, not in this length. Tightening further only makes the Delrin pop out.

The problem in the parting is that you can't use a tailstock. Well, I tried anyways with the tailstock pressure minimal. Eh, the results didn't put me in fear of my life or anything. But even though the parting tool went in at 90 deg to the work, the tip walked WAY off to the right, leaving the left side concave and the right side convex when all was done. This happened irrespective of how fast it was driven in.

Why did the parting tool's tip walk so much? I see Sherline recommended a 5 deg angle on the blade when viewed from the top. I'm not sure I see why, that would seem to make it cut unevenly to me. I can't tell for sure what angle my blade does or does not have.

I kinda wanna just hold a hacksaw over it now and drop it down to cut it...

I found that with.... I guess it's about 3" long part with a 3/4" new diameter- the end face couldn't be finished either because again the jaws can't hold that stable without a tailstock, but the SteadyRest will probably cure that. In fact I might be able to use the SteadyRest instead of the tailstock for the parting operating, right? Still won't fix the real problem of the parting tool wandering though.

I would shorten up the parting tool blade to just enough to part off the part.
you may have to use the steadyrest to support the part when you are machining it. you may want to try only drilling and machining enough for one part at a time keeping the rough stock solid for better support.
Kevin