Talk to me about: Lathes!   - Page 1
Forum section: electronics / general

author: Mark
author_rank: Frequent Contributor
timestamp: June 12, 2015, 02:14:07 pm
content: Hello all,I am working on a project where I need some high voltage feed-through insulators. I can find something suitable on aliexpress, but the shipping is the killer. So, given that these terminals are quite simple in construction, I'd like to try making my own by using HPDE and a lathe...HDPE rod:http://www.ebay.co.uk/itm/161444279000Pics of what I'm trying to make are attached.HDPS rod is 50mm diameter. Can I work with this on a lathe, and what sort of lathe would I need? What about the Proxxon FD 150/E?Connection is M8 bolt.

author: kripton2035
author_rank: Super Contributor
timestamp: June 12, 2015, 02:31:33 pm
content: I find proxxon lathes too small for their prices, and not that more preciseyou've better invest in a tool like this one a sieg sc2, it's bigger, but you can do more different jobs with itthe proxxon will be limited to very small pieces.http://www.arceurotrade.co.uk/Catalogue/Machines-Accessories/Lathes/Model-C3-Mini-Lathe/Model-Super-C3-Mini-Latheand you have free delivery until 30th september...

author: KJDS
author_rank: Super Contributor
timestamp: June 13, 2015, 05:21:17 am
content: I bought one of theseI did look long and hard at the Siegs, but decided that if I was going to have a lathe it would be a decent sized one. Slowly working on getting it back to excellent condition. The CNC section isn't working but I'm only interested in it's performance as a manual lathe.

author: mtdoc
author_rank: Super Contributor
timestamp: June 13, 2015, 05:41:08 am
content: Quote from: kripton2035 on June 12, 2015, 02:31:33 pmThat looks almost identical to theHarbor Freight Mini Lathesold here in the US. I suspect it may be from the same Chinese manufacturer. There are several YouTube video reviews of it.

author: tautech
author_rank: Super Contributor
timestamp: June 13, 2015, 05:47:12 am
content: Turned a bit of Nylon 6 in the past with an old 3 ft bed lathe, it was like turning cheese, it was so easy.Reasonably high speed for a nice finish and I just used HSS tooling.If you can chuck it, I'd imagine nearly any lathe would do it as the power requirements are very low.Currently I have a Harrisom 12", L6 Mk3, 40" BC

author: Paul Moir
author_rank: Frequent Contributor
timestamp: June 13, 2015, 05:49:12 am
content: The Sieg lathes are kind of like an assembled kit. You'll learn a lot getting it all set up to run super nice but you do have to spend some time at it. Given that you're in the UK, I would look hard at the arceuro ones mentioned above as they are built to a better specification by Sieg. The 7xs are about the smallest, cheapest lathes you can do real work on.Bed length is crucial on a small lathe. For example, one thing you find you often want to do is drill out the centre of your work. For that, you loose a lot of bed length with the drill, tailstock and chuck. For example, on my (non-Sieg) 7x10, which is really a 7x8, there's only about 6" between the end of the chuck and the tailstock drill chuck. So that means the largest piece I can centre drill in one go is 3" (3" of work and 3" of drill bit). The 7x14 is 6" longer, meaning the largest piece you can centre drill is 6" long. Big difference!To get you out of that, you can actually pass your work through the headstock and get yourself a lot more room. This is another critical thing to look at in a lathe; the headstock bore size. It also allows you to work on long shafts with one end sticking out the end of the lathe. The 7xs are a little over 16mm. I also have a 10x20 which has a 25mm+ bore which is far more useful.As for swing, the swing over the bed is not nearly as important as swing over the cross slide. This really is what limits the diameter of the work you can do outside machining on. There are ways around it but none of them are fun.If you expect to do a lot of threading on the lathe, the change gears are a little tiring and you should look for a lathe with a quick change gearbox. The classic cheap chinese lathe in this category is the 9x20, but I find it far too spindly a machine at under 300lbs (another useful measure of a lathe BTW).EDIT:Yes mtdoc, both are made by the same company in China:http://www.littlemachineshop.com/gallery/photos.php?Qwd=./2004-06%20SIEG%20Factory%20Tour%20China&Qif=PICT0307.JPG&Qiv=thumbs&Qis=MHowever there are several other Chinese companies making competing 7x machines. There are subtle differences between them. Also Sieg builds them to customer specifications including quality.HDPE is super easy to turn with an awesome finish. That and 6061 Al is good starter material. Finally expect to spend about as much as you do on the lathe for tooling including measuring tools.EDIT 2, last one I promise!: The PROXXON has a die cast aluminium headstock? That alone is reason not to buy it. There's good reason every manufacturer of machine tools uses cast iron or some synthetic materials, but never ever aluminium.

author: KJDS
author_rank: Super Contributor
timestamp: June 13, 2015, 06:28:55 am
content: One of the reasons that I chose the lathe I did was that it came with a ton of tooling, four chucks, live center, tailstock chucks, a dozen quickset tool holders and a load of cutting tools too.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: June 13, 2015, 06:48:46 am
content: There's very good reasons to get a good used lathe if you can such as getting some tooling to get your started. Also they'll be fundamentally better tools with hardened ways, etc.Where I live used lathes are rare, so I went with Chinese ones. In the UK with your industrial heritage you might find something much better.

author: kripton2035
author_rank: Super Contributor
timestamp: June 13, 2015, 09:04:39 am
content: you need room for such big lathes, and also some equipment to move them : they weight some hundredS of kgsthe small (chinese) 7" lathes are IMHO a reasonnable size for the hobbyststhe micro lathes need micro tools that are not widely availableand with proxxon you need proxxons tools...

author: KJDS
author_rank: Super Contributor
timestamp: June 13, 2015, 10:10:29 am
content: Quote from: kripton2035 on June 13, 2015, 09:04:39 amWhen mine was delivered it was on the back of a 40 ton truck that couldn't get close to my house, so it ended up on a pallet track and was pushed up a big hill by me and an overweight unfit truck driver. I was concerned he was going to have a heart attack. As hobby lathes go, mine is huge, but more sensible things such as a Colchester or more normal Harrison, or even the classic Myford 7 can be moved around on flat concrete by one person shoving. Unless I was very space limited I wouldn't go with a mini-lathe, a similar amount of money will get you far more cutting power.I also want milling capability and I don't have space for a lathe and mill, so wanted the biggest lathe I could get to put a milling attachment onto. Milling attachments on small lathes just wobble.

author: tautech
author_rank: Super Contributor
timestamp: June 13, 2015, 07:48:04 pm
content: Quote from: KJDS on June 13, 2015, 05:21:17 amVery nice.Do you know of the Yahoo Harrison lathe Group?https://groups.yahoo.com/neo/groups/harrisonlathe/info

author: artag
author_rank: Super Contributor
timestamp: June 13, 2015, 09:24:26 pm
content: This is often a good place to find lathes and other machine tools in the UKhttp://www.homeworkshop.org.uk/

author: tautech
author_rank: Super Contributor
timestamp: June 13, 2015, 09:42:00 pm
content: Quote from: artag on June 13, 2015, 09:24:26 pmAlso Tony's great website with lots of history on all sorts of engineering gear:http://www.lathes.co.uk/

author: KJDS
author_rank: Super Contributor
timestamp: June 13, 2015, 10:07:05 pm
content: Quote from: tautech on June 13, 2015, 07:48:04 pmI've just joined, looks like lots of useful info

author: tautech
author_rank: Super Contributor
timestamp: June 13, 2015, 10:19:23 pm
content: Quote from: KJDS on June 13, 2015, 10:07:05 pmReal helpful bunch of guys there too, just like EEVblog.

author: ttt
author_rank: Regular Contributor
timestamp: June 14, 2015, 11:56:33 am
content: Quote from: Mark on June 12, 2015, 02:14:07 pmI'll give you my 2 cents: The second picture shows a round dome. If you need to make that part you will need special (expensive or DIY) tooling or a CNC lathe. Either way count on a couple of months of ramp up time to get good at making this stuff if you have never done any lathe work before.Manually drilling M8 holes precisely into the base like in the first picture is usually done using a dividing head. Those can be pretty pricey and also require some experience to use. You could just scribe your holes into the plastic but that gets old quickly. It also looks there are pockets for the screws. Those need to me milled.This can get complicated quicklyNow a lathe is a great tool to have no matter what (I have a 8x14 manual lathe and a BF20/G0756 mill converted to CNC). Keep in mind that to make a lathe really useful you usually need to spend more on tooling than the lathe itself.In the manual lathe market there are two major Chinese manufacturing companies:Sieg:http://www.siegind.com/products_list/&pmcId=31.htmlWeiss:http://www.weiss.com.cn/product/&pmcId=38.htmlMost of the new lathes and mills in this class you can buy across the world are variations of these machines (usually with customized colors, that's it). Be wary of buying old stock. Sieg and Weiss update their machines on a regular basis, usually for the better.Then there are 'hobby' lathes and mills:http://www.taigtools.comhttp://www.sherline.comThese are considered really good for very small parts. Jewelers and clock makers use these regularly. But these require way more setup work, they are not plug&play.The Proxxon looks very much like a Sieg 7x14. I would probably go for a Sieg or Weiss since getting parts and upgrades for these is much easier (littlemachineshop.com for instance). There are just so many of them out there.Finding a used old (UK made) lathe might be a really good option also. Not recommended for a beginner though unless you have an unlimited amount of time to fix stuff...

author: KJDS
author_rank: Super Contributor
timestamp: June 14, 2015, 01:19:05 pm
content: If you're considering a second hand lathe keep an eye onhttp://www.cottandco.com/en/http://www.ppauctions.com/sales.phphttp://auction.newengland.co.uk/

author: kripton2035
author_rank: Super Contributor
timestamp: June 14, 2015, 04:12:05 pm
content: the 3rd site has really nice items... shame it seems you have to collect them they dont send ...

author: cowana
author_rank: Frequent Contributor
timestamp: June 15, 2015, 07:16:53 am
content: I bought my mini lathe from Amadeal:http://www.amadeal.co.uk/acatalog/----span-style--font-size--16px------CJ18---100mm-3jaw---Metric-----span-----AMA_LA_CJ18_M_3JRB.htmlExcellent quality, and one of the cheapest prices I've come across - I'd highly recommend them.

author: kripton2035
author_rank: Super Contributor
timestamp: June 15, 2015, 10:34:45 am
content: the one at arceurotrade has a 500w brushless motor - so no hi-lo gear your's hasalso arceurotrade has a 400mm between centers, your's has 350mmbut I agree it's a very good price, they are simply not the same products.

author: cowana
author_rank: Frequent Contributor
timestamp: June 15, 2015, 10:53:11 am
content: I'd certainly agree that the arceurotrade one is the superior product.For the small amount of turning that I do, I couldn't justify spending £500+ on a lathe - the Amadeal model (roughly a Sieg 7x14) is a very capable tool and is enables me to do jobs I otherwise wouldn't have been able to.Sure it would be nice to have the space for a full size floor mounted lathe, but I might have to wait a while for that!Andy

author: TerraHertz
author_rank: Super Contributor
timestamp: June 16, 2015, 01:19:33 pm
content: Quote from: KJDS on June 13, 2015, 05:21:17 amI knew I shouldn't have opened this thread. Jealousy the only possible result.Oh well. *Someday* I'll have a bigger workshop, with room for (several) things like that. Someday...

author: m100
author_rank: Regular Contributor
timestamp: June 16, 2015, 02:26:08 pm
content: Whatever you do, practice on cheap material (maybe Nylon) first. Understand the feed rates, cutting depths and approach angles you need to cut effectively. Not sure if there are any night school engineering sessions left, maybe locating a local model engineering society could be useful?Quick change tool posts areinfintelybetter than 4 way ones. As suggested above maybe the Sieg C3 or similar from somewhere that has spares on the shelf and some backup. I can recommend Arc Euro although I've never bought a lathe from them. Their printed catalogue is free. Buying machine tools secondhand at any price level can be a minefield. A well maintained British built lathe that is decades old could be very good, but many on Ebay are often just knackered with a quick paint job. Spares can be expensive or simply non existent.Lots of further info here on the C3. Arc Euro used to offer a full presale stripdown and rebuild service, it's more or less essential for a new Chinese built lathe. I think they have stopped offering the service now, although they are possibly better built than they were say a decade ago, you could easily find swarf or sand in the castings and maybe the bearings or gear train.http://www.arceurotrade.co.uk/projects.aspxLathework by Harold Hall is a good basic text although there are a few later books with more specifics on the likes of the C3.http://www.arceurotrade.co.uk/Catalogue/Books

author: BillyD
author_rank: Regular Contributor
timestamp: June 16, 2015, 02:26:48 pm
content: Quote from: KJDS on June 13, 2015, 10:07:05 pmDoubleboost is a real gentleman of the machining world from Newcastle and has recently acquired a Harrison lathe and been doing some good work on it as well as improvements to it. Great video + production quality too.https://www.youtube.com/user/doubleboost/videos

author: Corporate666
author_rank: Unknown
timestamp: June 17, 2015, 05:05:11 am
content: Buying those little crappy Chinese hobby lathes is just like buying a crappy Chinese soldering iron. Will it get the job done? Well, it will heat up and melt solder... but it's night and day from a nice JBC.Will a crappy Chinese lathe spin and let you cut material? Well, it will turn and metal will get removed, but it won't be anything like a real lathe. I am always saddened when I see guys laboring with crappy Chinese junk and getting disgusting surface finishes, horribly over or under-sized parts, bad tool life and being unable to do many jobs on their lathes... and you realize it's just because the machine is junk.So, my advice is to forget buying anything made-in-China and just find a decent used lathe. A real lathe from the 1950's will let you focus on the parts you're making and you won't be fighting a POS machine. And a good used lathe will cost about the same (or maybe even less) than a new Chinese POS and will produce great results. And you'll probably get some tooling with it.As for HDPE, it machines fine - but you want relatively low RPM's and tons of feed. You also want a nice rigid machine and sharp tooling... HSS is better than carbide for HDPE/LPDE/Acetal and such.