First mod done.
And, suprisingly, it was a success. I have o-ring modded my brass collar (tophat & stem seat). I made a cutting tool from an allen-key (about an hour of winging it on a grind-wheel in the lathe’s chuck), then went at the brass. Any one of you lot would have cringed so hard your faces would have imploded. Gonzo machining. 😆
Yes, ok, it took me approx two hours, you lot would have done it in 20 minutes (probably less). I had to keep taking the bit off, checking it, trying to stuff an o-ring in it, back and forth. And what the hell is the deal with the o-ring?! MURDERS getting one in there. I destroyed five before I got the sixth in relatively un-scathed. I suppose there’s a trick to it?
Now I have to re-fill the bottle. 😮
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Oh… forgot to say; for O rings, buy a couple of dental tools. These small, slender pics look dangerous but they are ideal for picking out old O rings from grooves, and in pushing new ones into place. Just don’t puncture them while moving them around.
aloha,
walt
Congratulations Langa. Good job. All the advice I see is good, though. Most cutting is external, when looking at the chuck it rotates counterclockwise. Clockwise cutting is reserved for weird stuff like left handed threads or reversing the knurl cutters for deeper knurling. For internal cutting you can’t see the bit; I use a small hand held mirror during setup because my lathe is too big to climb up onto or look over… but during internal cutting I”m watching the dial gauges to determine how much cut I have and stop often to measure to see how far I have to go. I don’t have DRO on my lathe (I’m poor), so I just set up my small dial gauges to read off how far the saddle is moving. Dial gauges are cheap. What you say about convention is surely true; but as you have seen, cutting in the reverse direction means grinding a tool on the opposite side. As you accumulate more experience and do more and more jobs, you’ll find that you’ll also accumulate a lot of different tooling, some for one time use but most re-usable in other jobs as well… but if you grind them for left hand cutting then they will only work in that direction and I cna’t be bothered to remember what each tiny tool was for, 30 years later, and which direction etc; so the convention does serve a purpose, if only to consolidate your tools so you don’t have to make more. Also, for internal cutting vs exterior cutting, I’m sure you’ve noticed by now that internal cutting means longer tool stretch from cutting bit to holder and thus WAAAAY more ‘spring’ in the tool, so you have to cut much much much slower for internal cutting (feed rate).
For O rings you can cut-n-try as you have been doing, but I like to plan it out on paper. Most O ring manufacturers give dimensions that work with their O rings, so you don’t have to guess at depth of cut. I used the Parker O ring manual, you can google it and download it for free. It’s a large manual, but really only the first couple tables are useful as it gives dimensions for various internal and external ring grooves.
aloha,
walt
Call me old-fashioned, I like to eye-ball my work, even when I’ve got dials and knobs that can do everything for me. And when it makes not a jot of difference to the work, why not? Convention?
Here’s the rub…the job got done. First tool I’ve ever made, albeit clearly over-engineered, and first bit of lathe-work I’ve done since 1980. Tell it to the hand, the face is wearing a smug grin. 😉 😆
Why did you cut your internal piece blind? Habit? Convention? Your lathe isn’t bi-directional? That would feel just too alien to me.
I used the hand wheels – They have little dials on them, amazing invention – Being able to see the inside hole doesn’t tell you much as eyeballing things isn’t a very accurate method to ensure the proper depth of cut.
Here’s some info you might find handy –
Yeah – it was the site that was messed up. Sites working and now its just the members that are messed up
Mine did that three posts ago too, the server was acting up. As I only just got over smashing my PC up a few nights ago I thought it best to restrain myself on this occasion and do a delete on the extraneous posts instead.
Well yeah, I know that much. I said I’m a fuck-witted noob, not a totally retarded gimp. 😆 I wouldn’t just be reaching over the work, I’d be unable to see what was happening too.
Why did you cut your internal piece blind? Habit? Convention? Your lathe isn’t bi-directional? That would feel just too alien to me.
my last reply wasn’t ment to be submited so many times but something happend with my computer and it decided to repeat the message several times so i think im going to have to stand the computer on its end aswell to teach it a lesson, and yes blodnob i can almost read now. and il soon be able to spoke proper england
I know, I know….because the tailstock is on the right.:wink:
When your turning the outside – which is the majority of turning, you’d be reaching over the work as the cutter would be on the other side and thats a big no no (unless your Lathe had its chuck on the right…. Why the chuck is on the left – I dont know).
I don’t know anything about that, and if an expert like you doesn’t I don’t need to feel like a plonker for being ignorant on the subject too. 😆
Like I said, I’m a bit of a winger. I wanted to see into the work and I’ve got a knob that allowed me to turn the chuck to suit my desire. It didn’t occur to me I was doing something odd. 😕
I’d be hard pressed to believe somebody would design the lathe to be bi-directional, then have the chuck spin itself off the spindle when somebody did a job with it turning CW. But what do I know, I’m a fuck-witted noob. 😆
Never mind, I got lucky and succeeded in doing an o-ring mod (with the chuck turning the wrong way, a gonzo cutting-tool and the toolpost at an illegal angle ). Yay for me, next week the lottery. 😆
Thanks for the input chaps. And very handy to know my next cutting tool can be square instead of round. It was an absolute bastard getting a nice radius on it.
There’s probly a reason for the direction choice. Not being an engineer i wouldn’t know it. But. Let’s assume peaple much cleverer than us decided thats the best way to go. Untill some one says it’s not right , al probly just plod on in the same direction.
Ah, I see. My chuck’s direction is reversible, so I had it rotating CW. If I’d had the cutter going in the opposite direction I’d have been unable to see into the work.
YN, your cutter is square. I figured it should be round, to make a good seat for the o-ring. Mine did start off with a nice length, but by the time I’d finished grinding it I was down to table-leg syndrome. 😆
Does it actually matter which side you cut on, so long as the rotation matches the tool’s cutting edge? I had absolutely no problems with my cutting. 😕
YN,
Your sticker fell off your tool post. Just thought you should know 😛
Langa,
Here are some pictures I just took with a piece of scrap brass showing what we mean – gives good results.
In these two pictures I extended the allen screw out a bit just so the toolpost wasn’t blocking the shot. The Chuck would move counter clockwise in the picture below so the piece is rotating down onto the tool.
I used that tool a few years ago to cut an internal groove for my .308 Breech –
Same process, but you’d just use a smaller allen wrench.
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Thanks Walt, that o-ring info is really helpful. 😀 It crossed my mind on the day and ended up along the lines of “Nah, nobody would have that kind of stuff.” I had to make do with holding the o-ring and tool up to the light and eying it. 😆
So I’m now thinking it’s normal to cut an o-ring slot with a square tool? YN’s looks sweet enough.
This cutting in reverse (so to speak), is there any real important reason why it shouldn’t be done? All the others (the bigger boys 😆 ) are too busy having a laugh taking the piss to give me a straight answer. Apart from the chuck might spin off. 😕 I’m aware that a real cutting-tool is most likely configured so it can’t do it, but I made my tool to cut in that direction. All I know is it worked just fine. There was no issue with centre, I used shims that put it right on the money. No chatter, though it squeaked a bit until I increased the revs. All normal stuff I thought.
Edit: You’ve edited your post with further info, ignore the para above. Thanks mate, it’s appreciated. 😀 Oh yes, the tool was flexing a fair bit. As you say, it was a bit of a stretch. I just went gentle with it.