ajoeiam
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Newbie needs advice about a lathe
- Thread starter Old Guy
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Help Support Home Model Engine Machinist Forum:
Thank you very much TerryD.
Only about 1 hour ago I placed an order and got the Screwcutting book on order so will order that one as it could be useful with the next one
Hi Terry
I was thinking it might be a scam myself these people will try anything to get your money, but as far as using too much iCloud I doubt that because we don't use it at all and only if things are taken to iCloud automatically with out our knowledge that would be the only way there was any use at all, Something like every time you take a photo and transfer it to mac and it gets stored in iCloud automatically perhaps. The only time I remember anything going to iCloud was when I bought a kindle book and that was sent to iCloud and I had to download from there if I remember correctly. I personally have no need or wish to have any details pertaining to me floating around the internet cloud.
Thanks for the info
john
willray
Well-Known Member
Heh - I think you have a vastly over-optimistic opinion of the engineering under the hood of commodity Chinese machine tools
The machine in question uses a brushed universal motor, and appears to have only a 2-wire connection to the motor. I don't believe there's any way to command zero RPM from a universal motor. It's possible to electronically brake one, but this is not "powered" to zero RPM.
Hi again John,
Grinding toolbits in HSS is not so difficult. To begin I use a cheap small double ended bench grinder monted on a board with a home made adjustable support, nothing complicated. This is complemented with a simple set of card templates cut at various angles according to whichever tool I'm grinding, these are used to set the angle of the support rest. Not my idea, it was one suggestion of Harold Hall.
IA few years ago I built an adjustable cutter and tool grinding table with accessories and modified a small grinder to accept diamond coated cup or saucer wheels at one end. This was to the design by Harold Hall, a one time editor of Model Engineers Workshop magazine, but this is for much more complicated grinding but worth it once you have experience. The basic grinding rest is here and is designed to be made using only a lathe. Below is a picture of my version of the more advanced one, but the basic one is just as capable. The rest was badly damaged by water during a garage/workshop fire (I was well insured thank goodness) and I refurbished it after rescueing it a few days afte the fire was extinguished and the building made safe. Here are a couple of pictures.
1) Damaged grinding rest rescued following garage fire:
View attachment 139989
The rust was not as bad as it looks, it was mostly just surface rust without much surface penetration.
2) The same rest after refurbishment, the accessories were likewise damaged and refurbished:
View attachment 139990
Just shows what can be achieved with a selection of emery abrasive cloth and elbow grease. You can just about see a little of the modified bench grinder in the background, which is raised on a block of wood with a cup wheel fitted (the grinder not the wood!
Best regards
Attachments
The pics of the single tool is the one I attempted to use, the carbide tools were the ones that came with the lathe I used the one in the middle.
As for setting the tool height I put a centre in the tailstock and moved the carriage and tool post up to it and then shimmed the tool up to the centre point I don't know if this is the best way to do it
John
As for setting the tool height I put a centre in the tailstock and moved the carriage and tool post up to it and then shimmed the tool up to the centre point I don't know if this is the best way to do it
John
willray
Well-Known Member
Ok, now we're getting somewhere.
The carbide-insert tool you used is (at best) a threading tool. If you swing your toolpost over, it'll work like a normal turning tool since the inserts are all the same (though the seat angles may not be), but if you presented that point-in to the work, that's certainly not helping your surface finish.
Amongst your carbide tools, the one intended for turning, from tailstock towards headstock, is the one at the left of the photo. Present that to the work with the tool-holder perpendicular to the turning axis.
[edit] looking again, I take that back. I think the one on the left is actually supposed to be a boring bar. There should be one that's the mirror image of the one on the right, that should be for diameter turning, tailstock-to-headstock. The boring bar geometry isn't horrible for diameter turning though.
The HSS tool that you used is a sheer facing tool, intended for cutting in to, and facing the right side of a step diameter change, from smaller radius on the right to larger radius on the left. It also won't turn diameters for beans.
The tool ground most like how I would grind a diameter-turning tool (tailstock-to-headstock turning) is the 2nd from the left in your box of bits. Others might prefer different geometries for that, but that tip profile, minus the pocket removed from the left, is my go-to utility HSS diameter-turning profile. Again, presented shank of the tool perpendicular to the turning axis.
The best way I know of to get the tool adequately on center, is to grab a steel ruler or other long, thin, straight length of metal, and pin it between your work and the tool tip. Shim, or otherwise adjust your tool height until the ruler ends up perfectly vertical when pinned against the work. If it tilts "forwards" over the work, your tool is too high, and if it tilts "back" towards the operator, your tool is too low.
... and don't trust that your tailstock center is the same height as your headstock center...
Hi John,
I can understand your worries about personal data, especially if you are unclear as to how it all operates.
The so called 'cloud' is just a series of large data banks and servers. There are no personal details kept there just your content data which is encrypted and just about impossible to read (similar to many messaging services). If you have a Mac and or iPhone your images etc will be automatically stored and believe me that is so useful as a backup when inevitably things go wrong with your own machine, and like any machine that is sadly the case. Many people have lost valuable or cherished data (pictures, documents etc) if they have no backupwhen an hard drive goes poof! The connection to iCloud is simply that, a connection to a storage system, no personal details sent, that is why companies, organisations and individuals are happy to use the 'cloud', it is probably much more secure and safe than your home system especially when using wifi.
ICloud has end to end encryption of data which means that only your (trusted) machine can decrypt it when you recall it. To Quote Apple (whom I trust as much as I do anyone):
"End-to-end encryption
This means that only you can decrypt and access your information, and only on trusted devices where you're signed in with your Apple ID. No one else, not even Apple, can access your end-to-end encrypted data."
Best regards
TerryD
The centre Insert tool is not a thread cutter the angle is to big but is used for turning down bar stock as are the one on the left and right of that one being a right hand and the other a left hand turning tool. The best one to use would be the left hand one in the picture know as a right hand cutting tool.
The single HSS tool is also correct as a turning tool. The one you described as a turning tool to reduce the diameter is a boring tool.
In the box going from left to right the 1st, 3rd 7th and 8th tool are all for turning down the external material from a bar. The second is a boring bar. The 4th is internal threading tool the 5th is the external threading tool. The 6th tool is a parting off tool.
willray
Well-Known Member
Ah, Dalboy is right. I thought it looked fat, but my brain was not completely engaged when I posted.
Not a geometry I use for diameter turning. I suppose it's bi-directional. Anything else to recommend it?
I'm less sanguine about this one... Zero back rake does not make for nice diameter turning, at least not in my hands.
I'm surprised the set doesn't include the bog-standard right-hand turning geometry:
< https://www.metalartspress.com/howtos/sharpening-hss-lathe-tool-bits >
The little boring tool with a pocket and tip geometry like a traditional right-hand turning tool, thank you for that. I'll partially blame lack of coffee and being in a rush, but, I've actually never had cause to use a boring profile ground into a HSS blank. I've always had inserted (carbide or HSS) boring bars, and never thought about what one would do to make one with a simple HSS blank. I would have figured out the reason for the pocket eventually, really!
Will
No Worries Will I have that set myself and the company that I got mine from lists a description and diagram of each one that is how I know. The single one does give a good finish as long as you get the feeds and speed right. I also own the insert tools that are shown(as well as others)
Not that I have used them all as I also brought some decent boring bars
Thanks everyone isn't life so much more fun when you can post pics.
Now I'm not disagreeing with anyone just stating my thoughts at the time, I used the Carbide one in the middle because it was already mounted in the tool post which seems like it was the right one, I thought the one on the left was a boring bar as it has a round shaft and if you mounted it in to a hole the cutting point would stick out on the cutting side of the hole, I also considered the one on the left to be a boring bar due to the offset and if you put this into a larger hole that too would have the point on the cutting side of the piece I don't know why you would need an offset to turn down a diameter.
My thoughts on the HSS was why on earth have so many of them got grooves cut into the top edge of the cutting face and thought at least 2 might be for facing off. I thought that no5 might be the best for diameter cutting but thought it might be a thread cutting profile also, I figured 2 was a boring tool and wasn't sure about 3 as it has a deep scallop out of the top of the cutting point, and 4 was for internal threading, not at all sure about 1 at all. I will have have a look at everybody's appraisals. To be honest I hadn't expected all these tools to have the cut outs in the top edge what are they for
John
Now I'm not disagreeing with anyone just stating my thoughts at the time, I used the Carbide one in the middle because it was already mounted in the tool post which seems like it was the right one, I thought the one on the left was a boring bar as it has a round shaft and if you mounted it in to a hole the cutting point would stick out on the cutting side of the hole, I also considered the one on the left to be a boring bar due to the offset and if you put this into a larger hole that too would have the point on the cutting side of the piece I don't know why you would need an offset to turn down a diameter.
My thoughts on the HSS was why on earth have so many of them got grooves cut into the top edge of the cutting face and thought at least 2 might be for facing off. I thought that no5 might be the best for diameter cutting but thought it might be a thread cutting profile also, I figured 2 was a boring tool and wasn't sure about 3 as it has a deep scallop out of the top of the cutting point, and 4 was for internal threading, not at all sure about 1 at all. I will have have a look at everybody's appraisals. To be honest I hadn't expected all these tools to have the cut outs in the top edge what are they for
John
Hi Terry
Are you saying that whenever you put a photo onto your mac it also takes a copy to iCloud I didn't know that as far as storing anything I don't think we need to store a lot and I use a back up hard drive to keep what I want safe, I have a bit of a problem with the trusted device thing in that if someone stole you mac you wouldn't have a trusted device anymore to regain anything stored I suppose if your iPhone was also a trusted device there would be hope but as you can tell I know nothing about computers
John
trlvn
Well-Known Member
@Old Guy The HSS tool you attempted to use looks dull to me. See the bright line along the cutting lip:
The leading corner of the tool does all the cutting. It should be very sharp and you should expect to hone it periodically to keep it from rounding over. I like to use diamond paddles for honing. Done regularly, you only need to use the fine and superfine. The three surfaces that meet at the cutting edge should be very smooth and highly polished.
Honestly, the pre-ground HSS tools don't look well-sharpened and the geometry is questionable on several of them. A zoomable picture is at the following link:
https://www.chronos.ltd.uk/product/set-of-8-sct-solid-hss-lathe-turning-tools-12-mm-square/
Since they are only charging 38 pounds for a set of eight, it makes me wonder if the HSS is really up to snuff, as well.
Craig
The leading corner of the tool does all the cutting. It should be very sharp and you should expect to hone it periodically to keep it from rounding over. I like to use diamond paddles for honing. Done regularly, you only need to use the fine and superfine. The three surfaces that meet at the cutting edge should be very smooth and highly polished.
Honestly, the pre-ground HSS tools don't look well-sharpened and the geometry is questionable on several of them. A zoomable picture is at the following link:
https://www.chronos.ltd.uk/product/set-of-8-sct-solid-hss-lathe-turning-tools-12-mm-square/
Since they are only charging 38 pounds for a set of eight, it makes me wonder if the HSS is really up to snuff, as well.
Craig
Hi John,
I think from left to right:
1). Facing tool - to turn a face on a step change in dia. and get a sharp internal corner where it meets the smaller dia.
2). boring bar - internal dia.
3). 60° external threading tool;
4). 60° internal threading tool;
5). Unsure, looks upside down in box;
6). Parting off tool; (I use parting blades in a holder);
7). Right Hand plain turning;
8). Left Hand plain turning tool.
I don't care for tools with such sharp points, I much prefer a round ended tool, especially for a finishing cut but keep a pointed one for sharp internal corners (or to cheat if I need to get a sharp corner at a step I'll finish off with a parting tool). Having said that you can always re model some of them when you have experience and you can grind new shapes on the back end of others and use them flipped over. Another alternative of course is to learn to grind your own tools using HSS blanks and sell the Chronos ones at some time in the future. As far as the carbide indexable tools are concerned it looks as though the used tip has a problem.
I haven't commented on the finish you showed us earlier but looking again it seems as though it is a shaft of some kind as the unturned portion in the middle picture looks as if it is ground. In that case it could be a high carbon alloy steel which would be difficult to turn. The HSS blanks are arriving this a.m. but as I have the builders starting some work on the house it may be a day or two before I can come back to you. I'll send another message by 'conversations'.
Regards
TerryD
I think from left to right:
1). Facing tool - to turn a face on a step change in dia. and get a sharp internal corner where it meets the smaller dia.
2). boring bar - internal dia.
3). 60° external threading tool;
4). 60° internal threading tool;
5). Unsure, looks upside down in box;
6). Parting off tool; (I use parting blades in a holder);
7). Right Hand plain turning;
8). Left Hand plain turning tool.
I don't care for tools with such sharp points, I much prefer a round ended tool, especially for a finishing cut but keep a pointed one for sharp internal corners (or to cheat if I need to get a sharp corner at a step I'll finish off with a parting tool). Having said that you can always re model some of them when you have experience and you can grind new shapes on the back end of others and use them flipped over. Another alternative of course is to learn to grind your own tools using HSS blanks and sell the Chronos ones at some time in the future. As far as the carbide indexable tools are concerned it looks as though the used tip has a problem.
I haven't commented on the finish you showed us earlier but looking again it seems as though it is a shaft of some kind as the unturned portion in the middle picture looks as if it is ground. In that case it could be a high carbon alloy steel which would be difficult to turn. The HSS blanks are arriving this a.m. but as I have the builders starting some work on the house it may be a day or two before I can come back to you. I'll send another message by 'conversations'.
Regards
TerryD
Hi John,
I also have a back up disk which is all very well if it doesn't fail as did an earlier version of mine when I would have lost a lot of data (pictures, docs etc) if I hadn't had 'cloud' storage. In fact many of my pictures are up on Flikr and Photobucket (the free accounts) as well but are set to 'private' so only I can access them, you can't be too careful.
As for a 'trusted device', my last pc was one but when I built my present one it was no longer trusted, however there is a convoluted process of 2 stage identification which involves phone and/or email as well as identification data, which again is encrypted, in order to get a new device trusted. By the way from 5gb storage to 50gb cost only £0.79p per month
We really should have this discussion privately as it is way off topic. PM me
TerryD
This diagram may help?
https://www.theengineerspost.com/wp...1524889401899-min.jpg?ezimgfmt=ng:webp/ngcb19
And on a small lathe like this (similar to mine) I find it best to always use SHARP tools, - e.g. HSS tools or Carbide inserts for ALUMINIUM (Not cheaper ones for steel!).
The Carbide inserts for steel that I have experienced always need to be "honed to sharp for best work. The small lathe just does not have the torque and STIFFNESS to handle the loads that are required to make the carbide inserts for steel work properly.
So, I use the HSS tools and keep them sharp.
I rarely take more than a 0.020" cut - as the swarf can be too strong to break into chips - but usually many cuts of ~0.010 are good for this size of lathe. HEAVY cuts can be made, but the whole thing starts to twist under heavier loads, so you lose PRECISION.
This is a hobby, so "manufacturing production" speeds and feeds are not suited to "Hobby" lathes. If you need big speeds and feeds then spend 10 times more on a heavy industrial machine that is designed to do the work.
But if making precision models, take it slowly, carefully, and enjoy the whole experience. - It works for me. Life is not a race: the only race is "the Human race"! Relax and feel good about your work, and you'll enjoy it.
Centre tools with a rule - as above - then cut across an end of bar and the cutting centre will show you how accurately you have set the tool. - A centre "pip" means the tool is a fraction too low, but a pip that gets "pushed-off" by the tool means the tool is too high. - High is worse than low for anything as the tool will not cut properly but need "HIGH LOADS" to make it work. Too low, and there is a chance of the tool digging-in... but keep the tool end close to the tool post (a long whange hanging out is just bad practice! - It needs to be short and stiff for good work). - I never extend the cutting end of the tool more than 2 x tool-bar thicknesses from the tool post. - except where there is no other way, such as when boring. I.E. a 1/2" square tool MUST NOT extend more than 1" from the tool post support. But a 1/4" base beneath a carbide tip at the end of a 1/2" bar really needs more support, for the heavy cuts it is designed for. Which is one reason a 1/2" of HSS works so much better.
The STIFFNESS of a 1/4" bar is 1/8th of the STIFFNESS of a 1/2" bar. So, the tool is just poorly supported and will vibrate under cutting loads, at the natural frequency of the stiffness of the bar. When I use a Carbide tipped tool, there is only the MINIMUM of tool extending from the tool-post - and I sharpen with a diamond hone to give it the best chance of doing the cutting (shearing of metal) that I want it to do.
Enjoy making precision parts - not swarf and scrap!
K2
https://www.theengineerspost.com/wp...1524889401899-min.jpg?ezimgfmt=ng:webp/ngcb19
And on a small lathe like this (similar to mine) I find it best to always use SHARP tools, - e.g. HSS tools or Carbide inserts for ALUMINIUM (Not cheaper ones for steel!).
The Carbide inserts for steel that I have experienced always need to be "honed to sharp for best work. The small lathe just does not have the torque and STIFFNESS to handle the loads that are required to make the carbide inserts for steel work properly.
So, I use the HSS tools and keep them sharp.
I rarely take more than a 0.020" cut - as the swarf can be too strong to break into chips - but usually many cuts of ~0.010 are good for this size of lathe. HEAVY cuts can be made, but the whole thing starts to twist under heavier loads, so you lose PRECISION.
This is a hobby, so "manufacturing production" speeds and feeds are not suited to "Hobby" lathes. If you need big speeds and feeds then spend 10 times more on a heavy industrial machine that is designed to do the work.
But if making precision models, take it slowly, carefully, and enjoy the whole experience. - It works for me. Life is not a race: the only race is "the Human race"! Relax and feel good about your work, and you'll enjoy it.
Centre tools with a rule - as above - then cut across an end of bar and the cutting centre will show you how accurately you have set the tool. - A centre "pip" means the tool is a fraction too low, but a pip that gets "pushed-off" by the tool means the tool is too high. - High is worse than low for anything as the tool will not cut properly but need "HIGH LOADS" to make it work. Too low, and there is a chance of the tool digging-in... but keep the tool end close to the tool post (a long whange hanging out is just bad practice! - It needs to be short and stiff for good work). - I never extend the cutting end of the tool more than 2 x tool-bar thicknesses from the tool post. - except where there is no other way, such as when boring. I.E. a 1/2" square tool MUST NOT extend more than 1" from the tool post support. But a 1/4" base beneath a carbide tip at the end of a 1/2" bar really needs more support, for the heavy cuts it is designed for. Which is one reason a 1/2" of HSS works so much better.
The STIFFNESS of a 1/4" bar is 1/8th of the STIFFNESS of a 1/2" bar. So, the tool is just poorly supported and will vibrate under cutting loads, at the natural frequency of the stiffness of the bar. When I use a Carbide tipped tool, there is only the MINIMUM of tool extending from the tool-post - and I sharpen with a diamond hone to give it the best chance of doing the cutting (shearing of metal) that I want it to do.
Enjoy making precision parts - not swarf and scrap!
K2
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Hi John,
The 'grooves' on the top of the HSS tools are there to provide a 'rake angle' which varies according to the material being cut. for example the proper top rake for Brass is zero while for free cutting mild steel it would be around 7° (I admit that I also use these to cut brass). Softer material such as copper or pure aluminium need even greater top rake angles. If you have a look in the Boxford book I sent there is a good explanation of the tool geometry on page 20. The tool holders discussed in this chapter of the book is now really out of date as QC toolposts have become more into the hobby market. I think that your guesses about the carbide tools are correct. I do actually have a set but very rarely use them.
By the way, if possible you should get to one of the larger model engineering exhibitions in the UK. I usually get to a couple every year but of course with restrictions in force these have not been run for a while. The Midlands model Engineering exhibition is a good one attended by people from all over the UKand is on Thursday, Friday and Satuday in the middle of October and is well worth attending if you get a chance allowing for the cost of fuel these days, although it is improving at the moment, but it would be at least a couple of hours drive for you (but mainly motorway).I'm not sure about any exhibitions in your area but I would expect there to be at least on big one. At these larger ones there are usually many main suppliers such as Chester, Chronos, rdg etc as well as private exhibitors ranging from small schoolboy example to 1/4 scale traction engine , loco from small to huge as well as clocks, homemade workshop equipment and many other types of model engineering including some very quirky ones. they usually have workshops which are free to attend such as metal casting, turning etc., and a great opportuinity to talk to others and buy materials - if you pre order you can collect on the day without sometimes extortionate postal costs.
Now I'm off to greet the builders!
TerryD
