Now that I've got the router side of things covered I'd like to be able to machine things like this:
I'm looking for something that will handle upto 70mm diameter 6061 T6 or similar aluminium and about 50-100mm length. Would like to be able to thread with it too.
Budget is around £1500-2000 max. If its not already CNC I'd be converting it and that has to be factored into the price too. Not even sure if I'd get more use out of a mill instead of a lathe. But for now I can use crawl around alu with router but I can't turn parts on it so a lathe makes more sense to me.
70mm diameter makes something like this mini-lathe too small. You could do it on one of those, but I can say from past experience that it would be unpleasant!
Next size up would be something like a Myford lathe, but they tend to be overpriced and are still a bit of toy really. What you really want is something around the size of a Colchester student (like I have), or a Harrison M250/300. Colchester student's go for around £500 on eBay, so well within your budget if converted to CNC, which wouldn't be necessary for the part pictured. The issue is they are very heavy, so unless you can get to your garage/shed from the road, it's likely to be difficult to get the lathe in place. Any decent lathe will be very heavy - you could probably judge how good a lathe is by weighing it.
Is a good place to start, they also have a for sale section.
Used lathes is a bit of an odd market, secondhand hobby size machines often go for more than industrial machines because it is such a pain in the bottom moving 2 tons of cast iron.
smart & brown lathes are some of the best ever made but 50 years of abuse will wreck any machine, if you are planning to do a conversion to cnc that will be less of an issue as you can retrofit modern rails onto it.
Smart and Brown L4 Lever Operated Collet Lathe | eBay
Smart and Brown. "L" Collet Lathe Very Light Use. | eBay
USED LATHE (SMART AND BROWN). | eBay
Smart & Brown 1024 Toolroom Lathe | eBay
I've had an ebay search setup for a few months for 'smart brown lathe' and I've noticed that a lot of these machines get re listed over and over again, just not that much demand for them.
There are also auction sites where cheap lathes pop up on from time to time.
If you are going to do a conversion you could always go the whole nine yards and just build one from scratch:
Scratch built CNC Slantbed Lathe - finished. - YouTube
I think the 70mm dia is going to be a problem if you need that much as the spindle bore. I quite like the idea of making your own from scratch as D.C. suggests. At the end of the day, a lathe is only a driven chuck and 2 axis, so something like the one in the youtube video is very much doable at home. The cost of parts is basically a CNC kit plus a motor and a VFD. I reckon you could make something real nice for less than £1000.
70mm through bore is a problem.
Most 'hobby' lathes are only 1"/26mm through bore, with some of the more common modern ones only being 20mm. Even once you go into more industrial lathes, to get 3" involves getting a fairly substantial lathe.
I've spent a fair bit of time lately exploring options to upgrade from my Conect, and I'm currently looking at a Clarke CL430 and machining the bed to accept linear rails. It still does limit me to 26mm through bore, but that's more than what I need for existing items. However I'd be looking to upgrade to a 2"/50mm headstock at some point.
I could probably pick up a used/scrapped large CNC lathe for not much money, but I physically don't have the room, or the power supply for that matter, and for what I usually make would be very much overkill.
You've got to decide what you intend to make, and what concessions you're wiling to make.
Might also be worth keeping an eye on the ex demo machines at Warco. I bought my WM16 desktop mill from them as an ex demo for £750 and it was like brand new apart from a couple of small chips in the paint. The bed was spotless, so I don't think it had ever been used to cut any material.
Used & Ex Demo - Warco - Quality Machine Tools
Thanks for the suggestions guys. Gives me plenty look at and I'm getting a clearer picture of what I'll be needing to do the parts I want.
The suggestion to DIY from scratch isn't feasible for me. Even converting an old lathe would be a big commitment in time and I wouldn't want to stretch any further than that. I'm definitely more interested in making parts than what makes the parts.
Seems that 70mm bore is indeed quite ambitious so I'll likely have to scale back the size of the parts to 50mm which seems more doable.
I'm not in a position to buy yet so I'm window shopping at the moment trying to get as much info as I can so I don't end up buying shite that doesn't do what I want.
Would these be able to handle what I have in mind?
Harrison 140 Gap Bed Centre Lathe , Very good condition | eBay
HARRISON M300 CENTRE LATHE WITH DRO £2250+ VAT | eBay
Problem is the 3 phase electrics, I could buy an inverter but you need a beefy 230v supply to start with and I'm not sure a 16amp socket will handle it.
I might be happier with an easy life and go straight with a 230v model which would likely mean waiting around for something on ebay or maybe buying new.
Warco GH1232 Metalworking Gear Head Lathe | Buy Warco GH-1232 Lathes
Buy Axminster CQ6230A-2/910 Metal Turning Lathe from Axminster, fast delivery for the UK
Just for clarification you was asking for 70mm dia turning space that could be done by a lot of lathes even a ml7 the 70mm bore that is being mentioned is through the head stock ie if you want to put a long bar through. Even quite a big lathe would not give you a 70mm bore the normal size for a bore would be about 20mm-30mm
dont understand need for 70mm bore.... need 70mm chuck capacity and 200mm+ between centres but that part could easily be turned on a minilathe... unless i missed something...
So you don't need this thing sitting in the bore of the chuck unless your feeding your bar through? Is that correct?
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