[Over Engineered]

Hi all,

This is my first post so g'day from Australia!

I'm just about to embark on making my first CNC router for making all kinds of cool stuff (hopefully).

The first thing I need to get is a decent metal lathe (mill is down the track but hoping to make a CNC mill instead of buying one :drowning: maybe ha ha) so I can make the majority of the parts I need myself at home. I started off looking at a Sieg C6 then went onto the C4 for better threading abilities and EVS control. Now through countless hours of researching I'm am thinking of getting a Hafco AL-320G from Hare & Forbes due to the slower speed capability and the 38mm spindle bore which opens up a lot more doors with what it can do. It's slightly above my price range @ $2189 inc gst (I was hoping for a $2K limit) but with all the extra features over the C6/C4 they would cost about the same to buy anyway.

This is the Hafco AL-320G: https://www.machineryhouse.com.au/L141

This is the C4: Sieg : CARBA-TEC

I already have an AC/DC TIG so I will make up a stand/coolant bay and coolant tank for it to help keep costs down a bit.

Is there another lathe in that sort of size/category/price range I should look at to compare or any other recommendations? I have no experience with them as of yet but that will soon change. I've done quite a bit of fab work over the last decade (carpenter/welder/builder) so it's not as if it's very foreign ground for me. I know many of you would have tonnes of experience with lathes (from fitter and turners to large scale manufacturing all the way through hobbies etc) so please help me out with anything I should be looking at/for and if I'm looking in the right direction or not.

Your help is greatly appreciated!

Kind regards

Steve

[Over Engineered]

(I just realised this is in the wrong sub-forum... Mod, can you please move it to "Benchtop Machines"? Sorry... :facepalmchair) )

Back to the lathe though... I also would like to convert it into a CNC lathe down the track. Accuracy is critical, hoping for less than 0.00002" max runout in a perfect world... I know this will vary from machine to machine...

The list I have to be turned already will be out of material like small 3mm 4340 round bar and threading it with a 0.5 M3 thread for robot suspension pins etc, graphite for nozzle throats up to 50mm ID, phenolic resin composites from silica, carbon, graphite etc for nozzles, 7050-7075/T6-T7651 aluminium nose cones from ~25mm-250mm OD (though the longer ones from ~600mm-1200mm will be made on a friends lathe), 7050-7075 aluminium bulk heads and stays etc for camera and/or electronics payload bays etc, lots of 4130-4140-4340 etc for axles, suspension rods, bushes, joints etc for 4x4s/trailers/robots etc (the 38mm spindle bore is a perfect size for this, Nissan Patrol ), various gears and cogs for future CNC projects (Mill, Router table/s, etc) RC robotics and turbines...

The list goes on but you get my drift. It needs to be accurate, reliable, not huge so I can still do a lot of tiny stuff but not so small I can't do the larger stuff. I think the AL-320G ticks all the boxes but I can't find any results on the runout accuracy that people have been getting with them? Another good thing about it is it weighs 280kg which is about double what the C4 weighs and about the same size roughly which would mean that it is better material hopefully. The only downfall I can see is that it won't cut a Metric 0.25 thread, could I make some gears for it so I can cut a 0.25 if I need too?

Any info/advice would be great! Again... Sorry for putting this in the wrong sub-forum...

Cheers

Steve

[handlewanker]

Hi, been a fitter and turner for 50 years or so, so here's my two pennoth worth........did you say accuracy to .000002" max run out?????....it will never happen on any lathe you can name.

For really small stuff with that run out specification you'd be looking at a watch maker's lathe, but they are small and mainly worked by hand.......you wouldn't be able to measure that run out even if it was present or maintain it with temperature fluctuations.

The Hare & Forbes model you named, in my opinion, is preferred to the Sieg anyday........go for the extra money, later you will kick yourself you didn't.

It has a number of features that are very desirable.....38mm bore, 5 Morse taper spindle, 3 Morse taper tailstock, taper roller bearing headstock, 160mm 3 jaw and 200mm 4 jaw chucks, hardened and ground bed, and most impressive a geared headstock.

It's a nice size lathe to have for general purpose work, and I don't think for that money you would go far wrong.

I would also include a quick change tool post as a must have feature......try twisting the dealers arm for a deal on the lathe with the quick change toolpost.

I wouldn't dream of attempting to convert that lathe to CNC, just too many unsuitable characteristics for CNC work.

For CNC, you'd best build one from scratch and make it dedicated for CNC.......all the bells and whistles on the manual lathe are not needed on a CNC lathe.

BTW, a thread with .25mm pitch.....and you're going to cut it with a single point tool?????....in Imperial notation that is 100 tpi.....you will need a smaller lathe too just for the very small stuff.
Ian.

[Over Engineered]

Hi handlewanker,

Nah I wrote 0.00002" (I know this would be fairly rare to find also but no where near a 0.000002" accuracy which as you said they would easily expand and contract more than that from a cold morning to the heat of the day). During my research I found this review of the Sieg C4 lathe, the one he had a guesstamation of 0.00002" he guessed as his Peacock one ten thousands incrumented DTI dial barely moved at all... It could be a bit off but that's some nice accuracy for a lathe in these price brackets Review: Sieg C4 Lathe

Like I said earlier I can't find any info of runout for the AL-320G's so was hoping for those same sort of figures from the higher priced (but slightly larger) Al-320G. If you would know (or anyone for that matter) what sort of run out I could expect from the AL-320G that would be great to know.

The reason why Im wondering about the 0.25mm pitch as that's what the C4 is capable of and was wondering if I could change the gearing in the AL-320G if I was ever in the need to do such a fine thread (who knows of I will but I will be nice to know what the options or modifications are.

The QCTP will be first on the list and I will try swindle Hare&Forbes into throwing one in as they want nearly $400 for delivery of the lathe (which is pretty steep I think). It is the first thing on my list to get apart from all the other stuff I'll need also...

So when you say I'll need a smaller lathe just for the smaller stuff, what do you think would be the smallest round bar I would be able to turn accurately on this machine? I know it depends on the runout amongst other things but I'm hoping to be able to thread 3mm rod with a 0.5mm pitch for a project I'm working on at the moment... Am I dreaming or could I luck out with the runout?

Forget the CNC conversion.

Thanks heaps for the info! I need all the help I can get at the moment!

[underthetire]

You would need an LVDT electronic indicator and amp to measure that kind of run out. The CHEAPEST LVDT with amp is about $2100.00 US. No way is a cheap peacock going to measure better than .0001. That kind of run out you will need a precision lathe with air bearing spindle, and those start at 100X your budget.

[handlewanker]

Hi, if you intend to threads 3mm diam at .25mm pitch you will be using taps and/or dies in the tailstock......cutting threads with a single point tool would be reaching for the Moon.....trust me.

To do small stuff you can either mount another small chuck to another backplate on the lathe spindle or have a small lever scroll type chuck held in the 3 jaw that will allow you to hold small work, probably up to 8mm diam depending on the hole thorough the chuck body.

If you need close tolerances for run out, working in hundreths of a MM is the best you'll get, that would be to tenths of a thou in Imperial, and I would not like to bore tiny holes with tiny boring bars to get the runout tolerances you mentioned.....there are other ways to get concentricity and drilling and reaming ain't one of them.

The old axiom of you can't scale Nature is very true for a small lathe......big hands on small handles makes life very difficult, and the small lathes sold on Ebay and elsewhere are not going to give tolerances like you mentioned.....it also takes a lot of long time hands on working with any lathe before you get good at the turning game......every lathe has it's own unique quirky characteristics and you have to work round them.

I'd say that the bearings in the headstock of the lathe, if they were angular contact or tapered roller, and correctly adjusted, would give you far more concentricity tolerances as they are made by the manufacturers.

You haven't said what experience you've got as regards to engineering general, and a lot depends on how you approach the jobs in the first place.

Tenths of a thou are usually grinding tolerances, so lathe work for a lathe that is new will still be in the settling down stage.

BTW, the speed range for the small stuff is in the upper thousands of RPM, so bigger lathes run at top speed constantly don't last long in the bearing department.

To sum up I would think that with the Hare & Forbes model you mentioned you won't be disappointed.

BTW, you can always re-calculate the gear train on the end of the headstock by applying the formula for cutting screw threads and adding the necessary different gears (bought in) as required.

BTW again, cutting metric screw threads means you need to leave the half nuts constantly engaged and just go into reverse at the end of the thread back to the beginning.....if you disengage the half nuts as per Imperial thread cutting you'll cross the threads at the start each time, that's why it's simpler to use dies for the small stuff.
Ian.

[Over Engineered]

Underthetire: Very true! At this stage, all I can go off is online reviews. Through reading that Sieg C4 review (whilst he did mention that the dial indicator needle barely moved at all and 0.00002" reading was a guess), he mentioned regardless that the C4 lathe he had, has a spindle bore run out much less that 0.0001". The Peacock DTI he used measures up to 0.0008" in 0.0001" increments that are also broken into 10 sections per 0.0001" so if it barely moved at all it could be true though yeah? Mind you it could still be a bias review as there is a link to the review on the Sieg website, it is the internet, I don't know... I do understand that a lot of accuracy comes with proper setting it up and experience (I get the later eventually I hope...), but at this stage I have to go off reviews and people with a hell of a lot more experience with lathes than what I have, and at the moment that is everyone... To be honest, I would be happy if I could set it up so it has less than 0.0001" run out. Is that just a dream with this lathe, I don't know? The main question is what can I possibly expect, accuracy wise, from this lathe after setting it up correctly? Like I've said, I can't find any numbers on this anywhere with this model?

Handlewanker: Thanks for letting me know. I'll just get some good quality taps and dies for those smaller thread jobs. Would you know what would be the smallest I could accurately turn on this sort of machine without cutting threads that is? Eg 3 or 4mm? I want to know what the limitations of the machine is (I know it is mainly the user). I'm pretty much starting out on this machine, I did a little bit on lathes at school but that was years ago so I'm basically a newby but everyone has to start somewhere. I'm wanting an accurate, solid machine I can learn on to keep frustration down do a minimum, a good tradesman never blames his tools but a good tradesman always has good tools to begin with. My engineering experience, I've done quite a bit of design and fabrication of tools and gigs for carpentry, lots of fabrication of structural beams and I beam roofs for houses that engineers have ticked it off no problems at all, made a 4 link setup for the rear of my 4x4 that has been ticked off and certified by Queensland mechanical engineers as well as a tray that has tool boxes built into the bed along with a 6 point ROPS that bolts onto the chassis all of which passed with flying colours. As far as milling and turning goes, nothing yet, but we all have to start somewhere. Like I said though I've been hands on since I finished school 12 years ago but I'm eager to branch off into mechanical and aeronautical engineering which I am trying to get into uni to do so next year. So this lathe is the beginning of a new journey for me. I don't know much about them yet but that will soon change. It will be getting used quite a bit (along with probably a lot of swearing :lol: ) so I would like to start off on the right foot rather than getting too pissed off at it later down the track. I don't know what to expect from a cheap lathe like this but I don't want to buy crap that can not be made better with mods or bearing shimming etc. The first project we are doing is a sugar shot to space rocket to try and film the curvature of the earth (yeah we're reaching for the moon ha ha ha) the working prototype is a 2250mm x 103mm 7075 T6 aluminium rocket, powered by a single twin stage motor that we will be casting ourselves. We are making everything ourselves apart from the silicon o rings for the nozzle, screws and cameras. Pretty much the whole thing needs to be made to within 0.0001" max, anymore and the risks of an off heading flight increase severely. I'll be making a CNC router so we can machine the fins and other flat parts precisely. It's a big project that will be challenging but it's going to be fun . This is why the accuracy of the machine is fairly crucial (the next is me ha ha). We don't have a time limit for launch so the stress of getting it done in time is null, we have all the time in the world to get it perfect (<0.0001" perfect) but it comes down to the machine. We do have a licensed mechanical engineer to offer advice when we need it. I just need a good accurate lathe for around $2K plus tooling etc.

How accurate could it be once set up as properly as it can be?

This is all new to me but I'm eager to learn as much as possible. Thank you all for taking time to help me out with your advice! It's greatly appreciated!

Steve

[underthetire]

All I'll say is remember the golden rule. You need something twice as accurate as what your trying to measure. Pretty tough to get a mechanical bearing to run in the millionths let alone a entire assembly. Hardinge spindles ( tool room lathe) are about .00005, they ground them on the machines, and last one we bought was close to 80k. Proper way to check run out is with a test bar made for the spindle taper, that way you can see what both the front and rear bearings are doing.

Sent from my G-Tab Quantum using Tapatalk

[Over Engineered]

So for $2k~ you get a ~$2k lathe, just have to work out the woes and setup as much close as possible. So you can machine grind the bore slightly to increase its accuracy?

What do think of this Paramount FI-910SM, there cheaper on ebay than that site. Will probably be the same price as the AL320G but with a QCGB so not as much messing around with gearing, jobs won't take as long etc... Is it as good a quality as the AL-320G and it does come with more/better features for around the same price yeah? It would cost about the same to get the al-320g to those specs correct?

Thanks heaps for the help and info!

[Over Engineered]

There is also this 1975 Hardinge Model Makers Lathe for $1500 http://www.machines4u.com.au/view/ad...-Lathe/124659/

If your saying ~$80K new price this must be clapped out for $1500 yeah or could that just be depreciation?

[handlewanker]

Hi, don't even dream of getting that lathe for the type of work you mentioned......it's like using a meat cleaver to do brain surgery......good for the big stuff, but now it's long past it's use by date.

BTW, run out is an ambiguous word.......where do you measure it?

When you hold a piece of metal in the chuck it's the chuck that you are depending on......and they ALL run out.

When you hold a piece of metal you are going to machine it so the finished diam will be smaller, and that is where the "runout" would show up, but as the bearings are adjustable and are right from the manufacturers, you would not get runout per se once you have machined the OD.

If you expect to get runout measurable to +- .00001" you're a better man than I master Jack.

The runout you think is important is only in the mind....the spindle will rotate very accurately in the bearings and so runout will be non existant.

By runout I imagine you are thinking that once the part is machined it will have a wobble in it......this is a totally ludicrous assumption.

Rest assured, the lathe you mentioned at Hare & Forbes will be far more accurate than you can ever manage to machine with, until you get enough experience to wear it out a bit.

You still have to learn to sharpen the cutting tools unless you are "advised" to buy a set of tungsten carbide tipped lathe tools and that is where your troubles will really start.

At the same time you'd better start learning to sharpen your drills if you want to do drilling for any purpose.....nothing like a drill that won't cut.

On the subject of how small in diam that can you turn.....the rule is the length to be turned (finished length) must not exceed 4 times the diam, so for a 4mm diam the max length you can machine is 16mm.....longer than that and you get deflection of the material, which makes runout a thing you just don't need to worry about.

All single point tools must obey this rule too, like boring bars, but drills are twin cutting edge and are balanced in their cutting characteristics so long drills are OK in this respect.

BTW once again, you'll also need a 150mm double ended bench grinder with coarse and fine stones for tool sharpening, that is if you are using High Speed Steel and grinding your own tools.

Along with the QCTP invest in a 13mm keyless drill chuck with 3 Morse taper shank, about $85 on EBAY.....it beats using a drill chuck with a chuck key.

For small drills up to 4mm you'll need the smaller keyless type, again on EBAY for about $45......it will need a 2 Morse taper shank as it's quite small and also a 2 to 3 Morse taper socket (sleeve) to fit it to the tailstock taper.

For really small drills, like up to 2mm diam, you can get a small sensitive drill chuck that slides on a sliding spindle and you move it with the fingers to get the feel of the drill.....about $20 on EBAY.
Ian.

[underthetire]

Thats not the tool room lathe. No feed or threading. Kind of an accurate 2nd op machine really. A DECENT used one from the 60's or 70's typically will sell 10-15K. There are a few REALLY nice knock offs out there.

http://hardinge.com/usr/pdf/turning/1332A_HLV.pdf

[Over Engineered]

Wow that's a nice machine! Maybe one day...

Your defiantly right about the old Hardinge, and figured it would need a lot of $$$ to make it useable again but again it's not in the same league as what I'm after/need.

For runout, well I don't know what to expect from the lathe, I do understand that each attachment will have its own runout, I just can't find any readings that people are getting with these machines, the machine only, if it's out at the machine slightly then you add a chuck that is out slightly (unless you can kind of counter balance them (I have no idea?)) it will add up to a greater run out correct? I just have no idea as to what I can expect from these machines as the only info I have found on runout to the cheaper lathes is the Sieg reviews I have linked. They have said 0.00002" of an inch so that's where I got that from. I don't know what to expect but with setting up I would like 0.0001" or less, like I said before I may be dreaming about that with these machines and I'm definitely no Master Jack. The reason I ask all the questions on runout is there is no figures that I can find on the net.

I do have a 2 stone (coarse, fine) bench grinder that I bought as a 1st apprentice (~12 years ago) to sharpen my drill bits every morning before work. I think I have got it ok though my 16-18mm drill bits I've put a 90 degree point angle on them as that makes them cut through treated pine rafters and gang nail plates like butter cutting the time taken to drill each hole well in half. If I need them for I'll regrind them to 60 degrees.

What I have found is this though 580713 - Buy Metal Lathe 36" Light &Guard | Gasweld

It is bigger (530kg vs 280kg of the AL-320G) and it's slightly more expensive plus shipping is $837.64, but it has a lot more fruits than the AL-320G that I would be looking at spending the money to add them to the AL-320G like a quick change gearbox etc further down the track. I can save another $200 on it if I get it shipped to a friends in Townsville instead of to my place (2.5hr drive from here.) It still only leaves me around $400 for tooling out of my $4K total budget but I'll need the chucks you have mentioned, HSS blanks, Carbide blanks (I already have the 150mm bench grinder) the QCTP would have to wait but the gearbox would make up for the lost time of that. The stand and coolant tank were never in my budget, 50x50x3mm dura gal verticals, 75x50x3mm dura gal horizontals and TIG weld up a 1200mm x 450 x 450 x 2mm thick aluminium or 1.6mm stainless tank with a Perspex sight glass so I know how much is in it which that will be gravity fed from above the lathe, a $20 1200mm fluro light mounted to the bottom of the tank to the stand so it's above head height and not in my eyes. I'll dynabolt the stand to the concrete slab in 4 corners.

If I can get it for a cheaper price would it be a better way to go over the AL-320G, I have around $1500 for tooling if I got the AL-320G rather than ~$400 with the CQ6230A, how much tooling do I need to get going? I'll be getting most of the tooling from CTC. CTC Tools Home Page

Is that getting too big for what I want to use it for?

Sorry for throwing the spanner in the works... Just want to cover all bases.

Thanks heaps for the help! Again I am far from a Master Jack! I honestly have no idea about lathes yet! Got to start somewhere though.

[lixingwen1987]

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[dexterbakus]

Hi, don't even dream of getting that lathe for the type of work you mentioned......it's like using a meat cleaver to do brain surgery......good for the big stuff, but now it's long past it's use by date.

i think STX INTERNATIONAL STX-3000-TF is all you need. its a best meat grinder with 3 Cutting Blades, 3 Grinding Plates, Kubbe Attachment and Sausage Stuffing Tubes