Will a 7" "asian" lathe handle this piece?

[great white]

I've been back and forth on buying a lathe. I was talking myself up to a new lathe in 10" size, but I can't justify (or comfortably afford) the prices they go for (1500 and up).

I have been watching for used, but its mostly too big, too expensive or too beat up stuff that shows up.

The busy bee tools 7" Asian lathes are pretty much big enough for everything I want to do (ie: bushings, spacers, etc) except for one thing I'm not sure it can handle.

I need to buy wheel adapters for my cars. They are built like so:



The spacer is 6061 aluminum, but the OD is 6" and approx 1.5" thick. Fairly simp!e piece and i have the skills to turn them out. To have them made in the custom size I need is going to be approx $500-600 (maybe a little more, won't know until I get a quote).

The lathe I'm eyeballing is the Busy Bee/Craftex CX704 (http://www.busybeetools.com/products/lathe-mini-7in-x12in-1-2hp-cx-series-csa.html) which is a 7x12 and will cost me somewhere in the 800-850 range once tax is added.

So to buy the lathe and build the adapters is only going to be a somewhere in the $200-300 more range than just buying the adapters. If i buy the lathe, when done I still have the lathe to use for my other small bits that I do infrequently.

The question I have is if the 7" lathe is going to be capable of holding and working the 6061 to a 6" OD?

I don't mind going slow, taking small cuts at a time and building them over a longer period of time. That's just the cost of using a smaller machine IMHO and I'm OK with that.

If the 7" can't handle it, its not as practical (financially) as just buying the wheel adapters.

Basically,I'm looking for the best bang for my buck. I'd just as soon buy the tool and build what I need. Not so much as a money savings, but to help justify the price of the lathe and have the tool for future work. If you get where I'm going with that line of thought....

 

[dracozny]

You should be able to do those on that size lathe. But the big question is: "Is this the largest part you will ever work on?" A larger lathe can do small work but a small lathe can't do anything larger than it is.

 

[great white]

Hmmm, looking again at the specs for the cx704, it seems there's only 2 1\8 swing over the cross slide. Does that mean a 6" turning is too big?

SPECIFICATIONS
Motor: 1/2 HP 110 V, 60 Hz, Single Phase, 3 Amps
Number Of Speeds: Variable
Swing Over Bed: 7"
Swing Over Cross Slide (RD): 2-1/8"
Swing Over Saddle: 5"
Compound Slide Travel: 2-3/4"
Carriage Travel: 10-1/2"
Cross Slide Travel: 2-3/4"
Maximum Tool Bit Size :5/16"
Headstock Construction: Cast Iron
Spindle Bore: 20mm
Spindle Size: 3"
Spindle Taper: MT#3
Range of Spindle Speeds: Low 0 - 1100, High 0 - 2500 RPM
Tailstock Travel: 2-1/2"
Tailstock Taper: MT#2
No. of Inch Threads: 18
Range of Inch Threads: 12 - 52 TPI
No. of Metric Threads: 10
Range of Metric Threads: 0.4 - 2.0mm
Bed Construction: Cast Iron
Overall Dimension of the lathe: 28" x 12" x 12"
Weight: 75 lbs
Warranty: 3-Years

The b1979 (similar price) lists a 4 1\2 swing over the cross slide, but has a "weaker" moto, shorter between centers dimension and doesn't seem to be a fully featured as the cx704:

Specifications
Swing over bed: 7"
Swing over cross-slide: 4 1/2"
Distance between centres: 8 1/4"
Spindle taper: MT3
Bore: 13/16"
Spindle speed range: 200-2500 RPM
Threading range: Inch 12-48 TPI
Metric: .4-2.0mm
Tailstock taper: MT2
Tailstock spindle travel: 1 7/8"
Motor: 1/3 HP, 110V, Variable Speed
Size: 28" x 11 3/8" x 11 1/4"
Gross weight: 47kg.
Carton size: 12" x 13 1/2" x 27"

 

[great white]

You should be able to do those on that size lathe. But the big question is: "Is this the largest part you will ever work on?" A larger lathe can do small work but a small lathe can't do anything larger than it is.

That's pretty much the largest I will work on at home. Besides, I'm also being held to a price point....

 

[dracozny]

"Swing over bed" means the largest Diameter that can be mounted without striking the bed. This does not necessarily mean the largest diameter that can be machined. "Swing over cross slide" would be the largest diameter that will clear the cross slide on top of the carriage.

One could probably face a short-legth work piece close to the "swing over bed" diameter on most lathes, though it might require two cuts - one with the tool on each side of the toolpost - if the travel of the cross slide is not long enough. You might also be able to turn the OD of such a piece using a boring bar.

 

[great white]

Ah, 6" diameter piece on a 7" mini lathe: http://www.mini-lathe.com/mini_lathe/reviews/sieg_sc2/sc2.htm

Gent had to make an offset tool holder. Neat idea. I'm pretty sure that would work for me.

When I get in to Halifax next month, I think I'll have a look at the cx704. Nice thing is busy bee sells a lathe mill attachment for the cx 704 for 300 bucks. That would add a little more versatility to the lathe and I can by it further down the road a bit to spread out the cost....

 

[Eddyde]

You might be able to turn the 6" work using a left hand tool holder, provided you can get the tool post forward enough on the cross slide.
How are you planing to do the bolt holes?

 

[DMS]

6" is pushing the 7x series pretty hard. The main issue is that when you get going slow enough to turn something that large, your torque drops off. I have seen some folks create jack-shaft reducers to give more torque at low speeds. It is very doable, but an additional project. I had a 7x14 when I first got started on this hobby. Can't recall the largest aluminum part I ever turned, but I did do some 4" steel parts. That was really pushing it.

The 9x series is also pretty popular, and (at least in the US), the cost difference is not that great. There is also the 8x series, which is not as popular, but is supposedly much stouter than the 7x series.

I think you could do the part on the 7x (unless you intend to bore those pockets, that will require an offset mounting, and a much larger swing), but it is really going to be pushing that little guy.

 

[autonoz]

HF 8x12 is 999.99. Use the 20 percent off and it is about the same cost as the busy bee you quoted. I've had one and it did not give me any trouble.

 

[great white]

HF 8x12 is 999.99. Use the 20 percent off and it is about the same cost as the busy bee you quoted. I've had one and it did not give me any trouble.

Unfortunately., shipping cross border would push that back up well over the price I would pay for the busy bee. Figure at least 150 for shipping, then taxes and duties at the border. The final insult will be "brokerage" that be every shipping company (besides USPS) dings us with. Brokerage on 1000 bucks will be pretty Mich double the shipping again . might as well buy the 10" from busy bee.

Good ol' drill press will make the stud holes. The important measurements are the hole spacing (asw well as the stud diameter), the spacer thickness (to correct offset/baxkspacing) and the cener bore since it rides on the hub center of both the wheels and the spindle hub. The 6" OD and have a tolerance of about 1\8-1\16 (over or under) and still be fine.