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Kiwi Bloke22/04/2023 10:31:17
912 forum posts
3 photos

^^^^^ Agreed!

paul mcquaid22/04/2023 14:48:20
34 forum posts
12 photos

thumbs up

Nick Wheeler22/04/2023 15:25:40
1227 forum posts
101 photos
Posted by paul mcquaid on 21/04/2023 15:31:43:

Sorry everyone for not realising I needed to put down my personal information and have realised it come under settings instead of being labelled Personal Information. it is all completed now though. I hope I haven't offended anybody for my rant. I was Polite when I spoke to Myford, Not very happy with the lack of explanation.. But realised I wasn't going to get it sorted any other way so bit the bullet and paid the £150. So at least I can get on with learning how to check the trueness of the lathe now... Fingers crossed.

Just checking it requires more knowledge, skill and judgement than you currently have, which is proved by your chuck experiences.

Put the effort into actually using the machine to make some simple parts appropriate to your requirements for buying it. Then you'll be in a better position to fiddle about with the alignment, assuming that it's even necessary - I bought my lathe 8 years ago, and the installation procedure was to carry it down the cellar steps, stagger across the floor, plonk it on the bench and plug it in. It's never been bolted down, and the parts produced have always worked well enough.

Oldiron22/04/2023 15:56:37
1193 forum posts
59 photos
Posted by Nick Wheeler on 22/04/2023 15:25:40:I bought my lathe 8 years ago, and the installation procedure was to carry it down the cellar steps, stagger across the floor, plonk it on the bench and plug it in. It's never been bolted down, and the parts produced have always worked well enough.

Exactly the right thing to do Nick. Many beginners read up on things far too technical for their own good. Its ok watching dozens of videos and reading lots of books but use the lathe or mill for a while to see what it actually does or does not do. If you do not have the very basics you will not grasp the more techy bits needed.

The very first mistake the OP did was buy a 4 jaw SC chuck. the second was not reading up on how to actually fit a chuck to a backplate. Easy to bang your nose when blundering around in the dark.

regards

paul mcquaid22/04/2023 18:19:39
34 forum posts
12 photos

The reason I bough a 4 jaw SC chuck, Is I had read they hold the round bars better than 3 Jaw and my work is not going to be light brass etc, but heavy stainless and maybe some Aluminium Round bar mainly and eventually maybe screw cutting for special bolts and bits.

peak422/04/2023 18:30:15
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2207 forum posts
210 photos
Posted by paul mcquaid on 22/04/2023 18:19:39:

The reason I bough a 4 jaw SC chuck, Is I had read they hold the round bars better than 3 Jaw and my work is not going to be light brass etc, but heavy stainless and maybe some Aluminium Round bar mainly and eventually maybe screw cutting for special bolts and bits.

So long as your round bar is actually round, then I'm sure you will be fine.
I do find mine holds the work quite tightly. The problems arise where the bar is rolled rather than drawn, and may be oval or otherwise out of round.
In that case you might need to change the orientation with respect to the 4 jaws to get it to grip evenly without wobbling.

Bill

Mick B122/04/2023 19:22:15
2444 forum posts
139 photos
Posted by paul mcquaid on 22/04/2023 18:19:39:

The reason I bough a 4 jaw SC chuck, Is I had read they hold the round bars better than 3 Jaw and my work is not going to be light brass etc, but heavy stainless and maybe some Aluminium Round bar mainly and eventually maybe screw cutting for special bolts and bits.

That's fair enough. The 3 jaw mayn't have the same grip, but it's horses for courses. I tend to find I need to use hex bar, both for models and railway work, plus I've never gone for records on cubic inches per minute metal removal. So the 3 jaw suits for me, with soft jaws to hold parts where there's not much to get hold of, and occasionally the 4-jaw independent for odd profiles and eccentrics. Hot-rolled black bar is something I've not seen in a while, though presumably it's still available.

I think it'd be quite unusual aluminium round bar work that the 3 jaw couldn't handle.

Edited By Mick B1 on 22/04/2023 19:23:36

Tricky22/04/2023 19:26:41
76 forum posts
8 photos
Posted by Mick B1 on 22/04/2023 19:22:15:

That's fair enough. The 3 jaw mayn't have the same grip, but it's horses for courses. I tend to find I need to use hex bar, both for models and railway work, plus I've never gone for records on cubic inches per minute metal removal. So the 3 jaw suits for me, with soft jaws to hold parts where there's not much to get hold of, and occasionally the 4-jaw independent for odd profiles and eccentrics. Hot-rolled black bar is something I've not seen in a while, though presumably it's still available.

You can hold hex bar in a 4-jaw SC chuck!

SillyOldDuffer22/04/2023 20:00:15
10668 forum posts
2415 photos
Posted by Tricky on 22/04/2023 19:26:41:
Posted by Mick B1 on 22/04/2023 19:22:15:

That's fair enough. The 3 jaw mayn't have the same grip, but it's horses for courses. I tend to find I need to use hex bar, both for models and railway work, plus I've never gone for records on cubic inches per minute metal removal. So the 3 jaw suits for me, with soft jaws to hold parts where there's not much to get hold of, and occasionally the 4-jaw independent for odd profiles and eccentrics. Hot-rolled black bar is something I've not seen in a while, though presumably it's still available.

You can hold hex bar in a 4-jaw SC chuck!

Can it be done without scarring the bar?

In a hex bar the distance between flats is less than the distance between edges, so a hex has to be twisted at an odd angle to grip with four edges off-centre in the jaws.

Feels like a bodge to me because twisting risks crushing the corners of the bar without getting a proper grip on it. In comparison, a 3-jaw always grips flats perfectly, whilst an independent 4-jaw grips two flats solidly.

I'd expect to change chuck rather than hold hex in a 4 jaw SC, but perhaps it works better in practice than I imagine it will?

Dave

Pete Rimmer22/04/2023 20:44:29
1486 forum posts
105 photos

If 4 jaw self-centering chucks held any significant advantage over 3-jaws you'd see them everywhere, but as it happens they are not common at all.

3-jaws are superior is almost every way.

JA22/04/2023 20:55:37
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1605 forum posts
83 photos
Posted by Pete Rimmer on 22/04/2023 20:44:29:

If 4 jaw self-centering chucks held any significant advantage over 3-jaws you'd see them everywhere, but as it happens they are not common at all.

3-jaws are superior is almost every way.

Are you from Mars?

I never saw a 3-jaw chuck during my apprenticeship. Almost the only reason they exist is because no one with a brain can use one.

The only time I use one is to hold a fly-cutter.

JA

Pete Rimmer22/04/2023 21:15:52
1486 forum posts
105 photos
Posted by JA on 22/04/2023 20:55:37:
Posted by Pete Rimmer on 22/04/2023 20:44:29:

If 4 jaw self-centering chucks held any significant advantage over 3-jaws you'd see them everywhere, but as it happens they are not common at all.

3-jaws are superior is almost every way.

Are you from Mars?

I never saw a 3-jaw chuck during my apprenticeship. Almost the only reason they exist is because no one with a brain can use one.

The only time I use one is to hold a fly-cutter.

JA

You used a 4-jaw SELF CENTERING chuck for everything but holding a fly cutter?

Zan22/04/2023 21:23:16
356 forum posts
25 photos

A 4 jaw sc chuck is vastly superior to a 3 jaw. It grips much tighter so with it, the horror of the bar slipping when threading has gone. It grips lighter thin pieces more gently without crushing , it is highly accurate at all diameters. it holds hex bar easily and has no problem with cast bars

A chuck on a hobby lathe does not need an accurate register. My 5” is a loose fit on it which enables it to be clocked dead on centre, where it remains thus the accuracy The register is only needed if the metal removal is higher than the lathe is capable of giving I can easily take cuts of 6 mm on my S7 without any problems

Anybody who condemns a 4 jaw sc chuck obviously hasn’t used one I hardly ever used my 3 jaw fir so long, that I mounted it permanently on a milling vice rotation base ( also never used from new!) to form a spin fixture for the miller

so the OP should should skim his backplate then bolt the chuck to it and get turning Send me a pm if you want advice on how to do this

Edited By Zan on 22/04/2023 21:25:32

Pete Rimmer22/04/2023 21:35:56
1486 forum posts
105 photos

Course I've used one, they grip great for truly round stock but not better than a 3-jaw. Accuracy has nothing to do with number of jaws but quality of manufacture and state of wear. Same goes for gripping force for threading, 3-jaws are not reportedly poor for that because of some flaw in the design.

Where they fall over flt is on materials that is not truly round. Just like a 3-legged stool which sits stable on an imperfect floor where a 4-legged one will rock, the 4-jaw can allow stock to rock on 2 jaws where a 3-jaw will not.

As I said, if they did actually hold significant advantage they would be much more prevalent but they are not. You'll find perhaps one 4 jaw self centering for every couple of hundred 3-jaws.

JA22/04/2023 21:36:48
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1605 forum posts
83 photos
Posted by Pete Rimmer on 22/04/2023 21:15:52:
Posted by JA on 22/04/2023 20:55:37:
Posted by Pete Rimmer on 22/04/2023 20:44:29:

If 4 jaw self-centering chucks held any significant advantage over 3-jaws you'd see them everywhere, but as it happens they are not common at all.

3-jaws are superior is almost every way.

Are you from Mars?

I never saw a 3-jaw chuck during my apprenticeship. Almost the only reason they exist is because no one with a brain can use one.

The only time I use one is to hold a fly-cutter.

JA

You used a 4-jaw SELF CENTERING chuck for everything but holding a fly cutter?

Pete

My apologies. I miss-read your posting. (I should not post at night).

I have never seen a self centering 4 jaw chuck in my life. I don't intend to see one.

JA

Pete Rimmer22/04/2023 21:44:48
1486 forum posts
105 photos
Posted by JA on 22/04/2023 21:36:48:
Posted by Pete Rimmer on 22/04/2023 21:15:52:
Posted by JA on 22/04/2023 20:55:37:
Posted by Pete Rimmer on 22/04/2023 20:44:29:

If 4 jaw self-centering chucks held any significant advantage over 3-jaws you'd see them everywhere, but as it happens they are not common at all.

3-jaws are superior is almost every way.

Are you from Mars?

I never saw a 3-jaw chuck during my apprenticeship. Almost the only reason they exist is because no one with a brain can use one.

The only time I use one is to hold a fly-cutter.

JA

You used a 4-jaw SELF CENTERING chuck for everything but holding a fly cutter?

Pete

My apologies. I miss-read your posting. (I should not post at night).

I have never seen a self centering 4 jaw chuck in my life. I don't intend to see one.

JA

No sweat I am often guity of the same. I get corrected more when posting whilst tired.

I actually keep two identical 4-jaw independant chucks on my rack one with the jaws set inside and the other with the jaws outside. It was the late John Stevenson who gave me the idea when he mentioned that he did this because swapping the camlock chuck was far quicker than reversing all of the jaws. He was of course, quite correct.

Howard Lewis22/04/2023 21:48:48
7227 forum posts
21 photos

Tyhe argument is about horses for courses.

A 3 jaw can hold round or hexagon.

A 4 jaw INDEPENDENT chuck can hold sqaure or round material, and hold it more concentric, (or less eccentric ) than a 3 jaw. The concentricity depends upon how accurately you want to work.

A goof 3 jaw will probably hold work concentric within 0.005" (0.127 mm), in a 4 jaw indemdent, you can setb it to better than 0.00005" (0.0127mm ) if you wish.

AND, if wated / needed, work can be deliberately set eccentric.

I once reamed a 1"diameter hole, 1" from the edge of a 6" diameter piece of cast iron!

You select the tool best suited to delivering the result that you want.

Howard

Mick B122/04/2023 22:23:08
2444 forum posts
139 photos
Posted by Howard Lewis on 22/04/2023 21:48:48:

Tyhe argument is about horses for courses.

A 3 jaw can hold round or hexagon.

A 4 jaw INDEPENDENT chuck can hold sqaure or round material, and hold it more concentric, (or less eccentric ) than a 3 jaw. The concentricity depends upon how accurately you want to work.

A goof 3 jaw will probably hold work concentric within 0.005" (0.127 mm), in a 4 jaw indemdent, you can setb it to better than 0.00005" (0.0127mm ) if you wish.

AND, if wated / needed, work can be deliberately set eccentric.

I once reamed a 1"diameter hole, 1" from the edge of a 6" diameter piece of cast iron!

You select the tool best suited to delivering the result that you want.

Howard

A good 3 jaw can hold work concentric within 0.0002 - 0.0005" :

Clocking the WM250V

Some horses can run better courses than they used to.

If a 4 jaw S/C can hold bare hex bar, I'd be interested to know how. If I wanted to do that with one, I'd expect to make a slit bush in brass, bored to the across corners size of the hex bar (generally measured rather than calculated, 'cos of the usual break edges), much as I do when I need to hold square material in the 3 jaw and prefer not to disturb it by swapping to 4 jaw independent. For most purposes, there's no significant concentricity issue.

Edited By Mick B1 on 22/04/2023 22:26:42

Fulmen22/04/2023 23:14:51
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120 forum posts
11 photos

Zan might not be entirely wrong (but not right either).

They might work better on thin walled parts for the same reason that a 6SC (6-jaw Self Center) is even better. And they might even be more rigid than a 3SC assuming you get full contact on all jaws. But can you?

According to Wobbly Table Theorem you can always get a 4 legged table to be stable by rotating it. But that assumes point contact, while chuck jaws are anything but. So it might be worth a shot when working with one, but it's no argument for choosing it over a 3SC.

As mr Rimmer points out, if they were that superior we would have seen more of them by now. A 3SC is the obvious all-round choice. It will hold almost any shape reliably, and even cheap Chinese chucks can hold 0,03mm or better when new. Anything will wear in time, and cheap stuff tends to wears fast. But 9 times out of 10 they are the simplest solution by far. A 4IA will do anything the 4SC will do and a lot more.

Having a loose fit on the back plate is a simple fix for a loose chuck, but with a new chuck one should obviously try a slip fit first. You can always remove more metal later, adding it back is a bit more work.

Paul Lousick23/04/2023 00:43:33
2276 forum posts
801 photos

The first paragraph of Paul's post was " I am becoming increasingly frustrated about the lack of help for wanna be engineer's to start out. Without any basic knowledge" and as already said, machining is an engineering trade qualification which takes years to learn at a technical college.

Youtube is a good place to start for a beginner with hundreds of introductory videos about using a lathe and mill, such as those by Harold Hall (**LINK**) , Joe Pie (Piecynski), Quin at Blondihacks (**LINK**), etc

Paul

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