Finally got a lathe!

[LenVW]

I see the Briggs & Stratton “Vanguard“ motors are in the Argos as well.
Argos have been around for decades.

When you are machining the hubs . . . you can be successful with HSS or Carbide.
Just keep in mind that HSS may require grinding to maintain a sharp edge.
The carbide will hog out much more and at higher SFPM without exhibiting any wear. The only thing to watch out for is subjecting the carbide insert to shock loads.
Make sure the tool and the workpiece are securely supported and reduce any chatter that may occur.
Take your time and get comfortable with your equipment and tooling.
Use the NET to research recommendations for specific bearing setups and preloads.
Questions are inexpensive, mistakes cost you money.

 

[PeterT]

I'm on the same page as Darren.
Ya, you can make carbide work. But sharp HSS works every time all the time. It's a no brainer. If you have to sneak up on a dimension, why take chances? Just use what you know for sure will work.

I shared a real example in post #53 cutting aluminum. I dialed in half a thou on the cross slide & it took exactly that off, finish was excellent. No drama, no making it work. I deliberately found a picture that had a whisp of swarf on the tool. I've done the same on the compound at an angle (shallower DOC). It's just as happy taking much higher DOC. This is the sharpest nose in my arsenal, finish only improves with larger radii but has other cons, so kind of job dependent. I should have mentioned I use the same style/uncoated CCMT on turning & boring tools with same results.

There are so many styles & specs & variants of inserts, I find it rather perplexing to put them all in a common bucket named carbide & suggest they are shades of problematic for hobbyists. Here is a small sample from a catalog. Note the DOC vs feed rate window variation. All carbides, but meant for slightly different purposes. Now the flip side to that is geometry is geometry so one would think HSS grind could benefit from that, yet nobody has said much about that. So maybe if you chose the wrong insert for the application or a bad one that would explain your results & bias. I dunno. Post us a picture of what you tried & maybe we can see something. A lot of people get feed rate confused with DOC. My understanding is those graphs are meant to provide sweet spot ranges to encompass multiple factors of interest; efficiency, chip form, tool load.... factors that would be of interest to CNC production shops. But it doesn't mean the world blows up if you take a finer cut or slower feed. Now if you run carbide rough & micro frac the edge or chip it, or the lathe has some problematic wear, or bought a mystery brand with incorrect geometry or coating so thick it rounds the edge... ya all bets off. But one could say that about anything including HSS.

I probably wont convince you, nor is that my intent. We are free to run whatever makes us happy. But I also don't think its accurate to generalize like HSS is some miracle cure. Both will work in capable hands. Both will not work when not implemented correctly. Don't take my word for it. Lots of pictures on the net to judge for ones self.

 

[eotrfish]

But I also don't think its accurate to generalize like HSS is some miracle cure. Both will work in capable hands. Both will not work when not implemented correctly.

+1

I routinely take .0005 DOC using TCGT and VCGT inserts on 6061 Al, 642 Bronze, 360 Brass, 752 NS, TufMet T3 and Ampco 45. Coolant helps preserve the edges and get a 16RMS finish. YMMV

 

[Susquatch]

@PeterT & @eotrfish


I think it is good to have different opinions on here.

I guess we float in different boats. I don't have a huge selection of carbide to choose from, and I'm not going to a catalog to order a special insert and tool holder for whatever work I'm doing. Not all of us are as skilled as you either.

Of course you are right Peter, I over generalized and that wasn't fair.

My experience (obviously different from some), drives my choices and my advice to others. One too many times I tried to creep in on a dimension with carbide and ruined the part. The advice I got at the time was to use hss unstead. That worked for me. Therefore I only use carbide for rough cuts or when I can make a bigger final cut. But I routinely reach for hss when I need to creep in on a dimension. That advice, and my results now drives my advice to others. It probably isn't universally correct.

Of course, dull or worn bits change everything. HSS must be sharpened as it dulls and carbide inserts have to be replaced.

Maybe when my ears dry out I'll change that view.

While we are on the subject, perhaps I could seek your opinions on two related questions that come to my mind since I really am open to experimenting and new points of view.

For most common steels, stainless, cast iron, & aluminiums,

1. What inserts do you most often reach for when you want to creep in on a dimension? In other words, what actually sits on your shelf waiting for that assignment?

2. Same question when you need to make a nasty interrupted cut?

 

[eotrfish]

For most common steels, stainless, cast iron, & aluminiums,

1. What inserts do you most often reach for when you want to creep in on a dimension? In other words, what actually sits on your shelf waiting for that assignment?

When I need to creep in on a dimension +/- 0.0001" I'll use this hone. Abrasives can be your friend.

The male slide on these ferrule sets must end up at nominal dimension +0.0000 / -.0001 for a suction fit. I turn them to +.001 then hone. Honing is the preferred method of achieving this tolerance. There are other ways to do it but they all involve abrasive material removal.

 

[PeterT]

One too many times I tried to creep in on a dimension with carbide and ruined the part. The advice I got at the time was to use hss unstead. That worked for me. Therefore I only use carbide for rough cuts or when I can make a bigger final cut. But I routinely reach for hss when I need to creep in on a dimension. That advice, and my results now drives my advice to others. It probably isn't universally correct.

Well if you want to open up yet another can of worms, many knowledgeable machinists will argue that creeping up is bad practice regardless of cutting tool selection & this even dates back to early HSS days. Yet many of us do it. Probably more of a conservative human nature thing which seems right, but not necessarily grounded in best practice. For example (make belief BS numbers):

DOC sequence A: 15+15+5*+5 (where * is final measurement point dictating last DOC setting which might yield 4 or 6 final set but anyways intentionally close to prior 5. And 5 represents a known finishing sweet spot for the tool) vs DOC sequence B: 20+15+3*+1*+1+... (creeping up mode).
Supposedly A is better than B because you are as much as possible, replicating (normalizing) the preceding pass conditions as opposed to introducing new variables which are DOC dependent (chip load, tooling assembly load & of course many other variables through the chain). We can get away with sequence B creep-up in many alloys, but difficulties arise with other common alloys which work harden, or sticky ductile materials like coppers which deform. I'm pretty sure Stefan.G has an informative video clip on this very subject.

And as mentioned above, regardless of the path, you eventually arrive at the destination where the lathe has basically done its job within its practical limits. Further surface finish & dimensional control then enters the regime of grinding, lapping, honing if that's what the job takes.

 

[Susquatch]

Ya, pretty much all true. I get your point.

But the human nature guy likes to creep up on a dimension and this human nature guy likes HSS.

Btw, I was not setting a trap asking about your favorite carbide bits. I am genuinely curious and would like to try them.

 

[PeterT]

When I need to creep in on a dimension +/- 0.0001" I'll use this hone. Abrasives can be your friend.

View attachment 21542

Oooh, maybe we can arrange to meet one so I can take some measurements off that to replicate. Never saw that model before. I've collected a few pictures of similar gadgets (shop made Dalapena equivalents?). But my issue is the abrasive inserts. Some guys have adopted fragments of common abrasive sticks. I've bought some rectangular candidates from Asian tool supplier with good selection of fine grits, but even cutting them off to length with diamond (Dremel) wheel has not been fun. Just as we speak I'm having to re-size lengths of 3mm O1 drill rod. I've made so many clamp / clamshell / ID lapping gadgets I've lost count. Some work better than others. Its a pita process but necessary to fit reamed holes with the correct fit.

Does this Sunnen model still exist or a piece of legacy tooling yu acquired?

 

[eotrfish]

Does this Sunnen model still exist or a piece of legacy tooling yu acquired?

Peter

I'm pretty sure that this hone still exists. The stones and guide shoes are still shown on the Sunnen website but I can't find the link to the actual hone. I bought some stones for it a couple of years ago.

No problem meeting and measuring to replicate the tool.

Some rodmakers have "designed" a poor boy version of this which uses the Sunnen guide shoe and stones. This might be the way to go. I have a couple spare micrometer heads that you can have if you decide to go that way. See below..

Ferrule Hone

store.grayhacklerods.net

 

[deleted_user]

Peter

I'm pretty sure that this hone still exists. The stones and guide shoes are still shown on the Sunnen website but I can't find the link to the actual hone. I bought some stones for it a couple of years ago.

No problem meeting and measuring to replicate the tool.

Some rodmakers have "designed" a poor boy version of this which uses the Sunnen guide shoe and stones. This might be the way to go. I have a couple spare micrometer heads that you can have if you decide to go that way. See below..

Ferrule Hone

store.grayhacklerods.net

Thanks for pointing out another tool I need to covet

 

[PeterT]

Some rodmakers have "designed" a poor boy version of this which uses the Sunnen guide shoe and stones. This might be the way to go. I have a couple spare micrometer heads that you can have if you decide to go that way. See below..

VERY interesting thanks for link. The mic head would certainly provide some dimensional feedback I'm missing with my methods.

This is a shop based tool I suppose somewhat similar in principle, wider range of sizes

Series: External Hone « Tom's Maker Site

I'm finding that lapping (as in with compound) to be a rather messy & time consuming process. It has it's place but I think for the very last stage. Even then I don't look forward to it. Don't laugh too hard but this is my latest attempt. I discovered after measuring a range of my abrasive papers they have surprisingly consistent thickness in the 600-1200 range with the same brand Mirka or whatever I have ~0.007". So I machined some blocks with an annular offset allowance around the target finished shaft size. I trap the paper in the bloc & spin up the stock under power, traverse the block up & down the length. As paper wears, move it over slightly yields brand new abrasive. Its basically dry abrasion so quick to wipe off & mic check progress. The idea is that when the 2 surfaces bottom out I'm very close to size. Well... thast the idea. It still a by-feel process unfortunately. What it does a good job of is de-ovalizing the drill rod stock to circular which is inevitably 0.0005" eccentric & slightly oversize as new. But drilling & reaming a straight hole on the parting line of backer block line (with shim sandwiched) isn't a slam dunk & often I don't have the exact drill size. So I'm just about to try the same technique with a similar pre-sized Vee slot.

 

[Tom O]

Here’s another for a external hone.

Series: External Hone « Tom's Maker Site

 

[PeterT]

My latest in a series of abrasive 'trueing' gadgets in preparation for lapping. This one didn't take long to make & seems to have some promise. I've had to make quite a few part of O1 tool steel lately because they have machined features & then need to be hardened. But they all have to be pretty precise sliding fits in some kind of reamed hole. I came to realize early that O1 stock arrives oversize its nominal size by 0.0005 - 0.001". That is as advertised. No problem so far, actually desirable if you want to finish it down a bit. But the other issue is the stock is inevitably non-circular (elliptical shaped). So they could measure as much as 0.0015" different in one axis than another. That difference amount you can actually feel as an odd fit in a circular hole. Unfortunately just spinning the stock in a lathe against a flat stick stone or abrasive does not correct geometry, trueing an ellipse into a circle. The abrasive tool basically just goes along for the ride. Lapping does accomplish this task but can be a long messy process. A couple thou is actually a lot & typically requires progressive abrasives & wearing out laps along the way, so preferable to leave that for the very last step

I've made a few gadgets with varying degrees of success. This one seems to be working better than the others. Still room for improvement but I feel comfortable getting the stock within 2-3 tenths quite consistently which then makes lapping so much easier. I have some round abrasive stone sticks arriving from AliExpressLand but I realized I had the raw ingredients in form of inexpensive Dremel type grinding cylinders. I made up some holders from aluminum, drilled holes for (in this case) three 6mm OD stones. They are just epoxied into place for the tester. I believe they are 240 grit which is actually not bad for this task. Most of the adjustable clamp style honing tools I see have abrasive on one side & an inert Vee bar on the other. I'm not actually sure if that's more for alignment guidance because of the hinge joint but I decided to put 3 stones against the OD tangent at 120-deg apart for more cutting action & more or less equalized. The clamping bolt system looks crude but actually once its finger tightened you can actually feel it cutting vs gliding so not unlike lapping I suppose. This tester can do from 3-8mm dia stock. Probably it would be best to preserve a tool for specific stock diameter so it wears the same.

 

[PeterT]

My original lapping tool finished off the last 2 tenths. I'm going to improve this tool too.

 

[Proxule]

My original lapping tool finished off the last 2 tenths. I'm going to improve this tool too.

Any updates?

 

[PeterT]

No. not really. I completed the experimental job at hand & had to move onto the next task. I think the 'tri' stones are a low cost & viable way of correcting shafting like this, say the 1-3 thou range before proceeding to lapping. I would replace the cap screw with a knurled knob for a bit more feedback control.