buying a lathe?

[Chak]

Hello. This is my first time posting a new thread, so here goes:
My team has been considering buying a new manual lathe ever since we acquired a more space earlier this year. I'm imagining a benchtop lathe that can cut 1/2'' aluminum hex shaft easily. We don't really have a machining mentor, so we're a bit leery of taking CD's often repeated advice of buying cheaper used machines and fixing them up. So what would be a good lathe for FRC use? (basically 1/2'' aluminum hex shaft for us.) Is there a lathe your team had a very positive experience with? We're looking more for a good deal rather than for the best, most expensive machine in its class.

The second part of my question is whether a new lathe should be our next tool at all (thus the question mark at the end of the title). For some context, we already have a bandsaw, drill press, jigsaw, arbor press, etc. We've also recently bought a CNC mill, the Tormach PCNC 770, for the same new space. It's so recent, we're still unpacking the boxes. We also have a Sherline CNC mini-mill and a Sherline CNC mini-lathe. Yes, we already have a lathe, but it has a tendency to fail when working with 1/2'' aluminum hex shaft. Either the chuck loosens and the shaft wobbles out, or (very rarely) the motor stalls. In order to make it work every time, we have to go painfully slowly and re-tighten the chuck after every operation . For sheet material, we have access to a waterjet sponsor who gives us discounts. So given our situation and resources, is a sturdy manual lathe the best choice for our next tool?

[MrForbes]

A lathe will come in handy...and you might discover that you can do more than just turn 1/2" shaft with it. The bigger it is, the more you can do with it.

I can't offer any advise on new ones...my South Bend lathe was made in 1946.

[snoman]

A good new manual lathe is expensive. What is your budget? I assume you have 3 phase power? If you can find someone you trust to go look at used equipment you may be able to find a good used one for 800 to 2000. Good names are harding, south bend, atlas. Don't be afraid of something from the 40s or 50s oftentimes they are better built than the new 1s. Get something with a 3 and 4 jaw chuck and a collet bar is nice. As with any machine tool tooling can be expensive too. The sherline Must be junk anything should be able to handle 1/2 alu hex. Let us know how you like the tormach. We are looking for a manual mill

[BBray_T1296]

Originally Posted by snoman

Get something with a 3 and 4 jaw chuck and a collet bar is nice.

If you're primary use is for hex stock, a 3 jaw chuck is the obvious choice over 4.

[Munchskull]

Agreeing with what has been said above. Old lathes are going to be your best bet. Only the ones built strong will have survived. If you are wanting to save on price then get good with some dials and backlash that is how my team made most of our parts up to this year till we got two new DROs. One place to look is craigslist. See if you can check out/test out the lathe first before buying. Offten you will find 40's-50's era lathes there. Good luck with your search.

P.S. if you can get your self a Monarch lathe do it. My schools metal shop has one that most likely help in WW2, it is considered by our team and our metal shop to be the second best machine out of the six lathes we have.

[asid61]

We are in the same position (1/2" hex shaft work, only without the CNCs lol) and I've been searching Craigslist for four months now without finding any particularly good deals. Knowing your budget would be a big help here; I've been looking in the sub-$1500 range, but if you have $3-4k to drop on it it's considerably easier to find a good one. For example, this one appears to be in good condition right now, although you would still need to check it.
I would say be wary of most flat bed lathes- they seem to have problems holding tolerances, especially on the tailstock. This includes the Atlas lathes; even though many people really like them it's hit-and-miss, especially if you don't have a machinist mentor to help you check the tolerances. Although many old lathes are good, many of them are also bad, and without thoroughly checking all the tolerances on it you can't be sure that you're getting a good machine.
The Seig lathes, although made in China, are able to get good results (see this site) and for just working on 1/2" hex shaft it seems like a good deal. A very highly-reviewed lathe in the same size class is the Micromark series of lathes, which is nice if you don't fully trust the Seig line. They also have the handy cam-lock tailstock. Little Machine Shop also sells some good tools and a few machines.
You may also want to outfit the lathe with a 5c collet adapter (preferably a tru-set) so that your 1/2" hex stock runs true in a collet, which can run you $300 or more. This is so that less experienced students don't have to rely on a 3-jaw chuck and their iffy runout to drill holes and bore on-center.
Another extremely handy accessory would be a DRO, and if you have the funds definitely go for that. It makes anything with circlips 10x easier. Speaking of circlips, getting something to make very small grooves is hard to find. The Nikole Mini-Systems grooving tools are the best I've found so far, that or just grinding down a parting tool blade to the right width for your groove.

[RoboChair]

I know some people will be giving me flak about this, but seriously consider this one
http://www.harborfreight.com/7-inch-...the-93212.html

Now before we start a flame war here, I want to mention the pro's and con's.
The pro's
Small easy entry machine
Handles FRC shaft work just fine
Can be equipped with a dial read out on both axes for around 50 bucks
With a dial read out this lathe can hold 0.001" no problem(without pushing it)
It comes with more set up tooling than you will need
It is going to have a hard time severely maiming the operator

The con's
It is really only useful for Aluminum and plastic, steel takes some TLC to turn
It does require more basic maintenance more regularly
You are going to have a hard time doing large stock
Most of the extras it comes with are difficult to work with or will not last very long

I have used this exact model lathe to make parts for our competition robots and it is a very serviceable machine for smaller parts. If 1678 had no lathe and we could buy one of these and some choice extras on sale I would do it in a heartbeat.

[RoboChair]

Originally Posted by asid61

Speaking of circlips, getting something to make very small grooves is hard to find. The Nikole Mini-Systems grooving tools are the best I've found so far, that or just grinding down a parting tool blade to the right width for your groove.

You want a 0.040" parting tool from Little Machine Shop
https://littlemachineshop.com/produc...gory=202639332

[Jared]

Originally Posted by Munchskull

P.S. if you can get your self a Monarch lathe do it. My schools metal shop has one that most likely help in WW2, it is considered by our team and our metal shop to be the second best machine out of the six lathes we have.

Monarch lathes are quite good, but they extremely expensive to buy/maintain and are overkill for FRC. The 10EE's I use often have lots of issues with electronics - the vacuum tubes for the variable speed drive are unreliable, and sometimes don't warm up like they are supposed to. That said, they are an absolute joy to use!

[asid61]

Originally Posted by RoboChair

You want a 0.040" parting tool from Little Machine Shop
https://littlemachineshop.com/produc...gory=202639332

Those are ok, but you would still have to grind them down for 3/8" and smaller snap rings- those require a 0.029" wide groove, and the tools to make that cost $50+ unless you make your own. I recently was able to make my own Thinbit holder, and I highly recommend that route- it's very easy to make your own holders for indexable tooling.
Oh, you'll want a Quick Change Tool Post (QCTP). They make toolchanges super fast and height adjustments easy.

[Cory]

Originally Posted by Jared

Monarch lathes are quite good, but they extremely expensive to buy/maintain and are overkill for FRC. The 10EE's I use often have lots of issues with electronics - the vacuum tubes for the variable speed drive are unreliable, and sometimes don't warm up like they are supposed to. That said, they are an absolute joy to use!

I second that. We have a 10EE and while it's the finest lathe I've ever used and will likely outlive me, I would never, ever recommend it to a team that has never owned a lathe before and has no experience with machine tools. Any 10EE that the average FRC team can afford is going to need work put into it that is extremely tedious, time consuming, and potentially frustrating. There are a lot of resources online that can be invaluable, but it's way too much of a crapshoot for people who aren't familiar with machine tools and electronics.

A Hardinge HLV-H is a similarly excellent machine that has much more conventional electronics, but for a machine in good shape you're still looking at more than most FRC teams can afford ($10k-15k).

For the price the harbor freight lathe probably isn't terrible as a starter machine to get exposed to machining and to help you figure out what you want down the line once you're familiar with lathes and know what to look for. There's really no particular "benchtop" lathe that you can purchase new that will be the clear choice as a standout in quality.

Originally Posted by asid61

Those are ok, but you would still have to grind them down for 3/8" and smaller snap rings- those require a 0.029" wide groove, and the tools to make that cost $50+ unless you make your own. I recently was able to make my own Thinbit holder, and I highly recommend that route- it's very easy to make your own holders for indexable tooling.
Oh, you'll want a Quick Change Tool Post (QCTP). They make toolchanges super fast and height adjustments easy.

If you have a Thinbit holder, what is causing you to struggle to find inserts for small grooving? .019, .029, and .039 are all stock sizes from Thinbit. You can get them from Western Tool, or McMaster will source them for you with a 1 week lead time if you call and ask for them.

[asid61]

Originally Posted by Cory

If you have a Thinbit holder, what is causing you to struggle to find inserts for small grooving? .019, .029, and .039 are all stock sizes from Thinbit. You can get them from Western Tool, or McMaster will source them for you with a 1 week lead time if you call and ask for them.

I can find the inserts for it, but the holder itself runs $50+ if you don't make it yourself. Not to mention that the inserts, which are trapezoids of HSS, cost $15 each. For many teams that's not a problem, but we struggle with getting money to retool and suffer from inexperienced users breaking tools (the rate of which seems to be at an all-time low, which is good).

[Cory]

Originally Posted by asid61

I can find the inserts for it, but the holder itself runs $50+ if you don't make it yourself. Not to mention that the inserts, which are trapezoids of HSS, cost $15 each. For many teams that's not a problem, but we struggle with getting money to retool and suffer from inexperienced users breaking tools (the rate of which seems to be at an all-time low, which is good).

It's still not cheap, but last time we purchased from Western Tool, .029 uncoated carbide Thinbit inserts for nonferrous metals were "only" $12 ea. You may want to shop around a bit for a better price than what you're currently getting.

[ChuckDickerson]

Our team was in a similar position looking for a decent but not too costly manual lathe in the bench top class and last year purchased a Precision Matthews PM-1127-VF-LB:

http://www.machinetoolonline.com/PM-1127-VF.html

We have been very happy with it and feel it is ideal for our needs. Consider adding it to your list of models to compare to.

[FrankJ]

Originally Posted by RoboChair

I know some people will be giving me flak about this, but seriously consider this one
http://www.harborfreight.com/7-inch-...the-93212.html

....

The 7x10 & 7x12 lathes are mostly made in a couple of factories in China. Sold under a multitude of brand names. Actually not a bad choice for small work. Active hobbyist community that offers many improvements & support. Little machine shop has repair & upgrade parts. (You will be replacing the plastic spindle gears soon after you start using the lathe) I would go with the longest bed I could afford. The 10 in bed is really too short. The 12 in one is actually about 4 in longer due to differences in the way they are measured.

Little Machine shop 7x14 on sale.

You don't need 3 phase power for the smaller mills & lathes.

Mr Forbes: Our South Bend 9 in is a mid 30s vintage. It has the single lever quick change gear box.