Choosing a lathe - power cross feed vs comprehensive thread

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Jawn
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Choosing a lathe - power cross feed vs comprehensive thread

Post by Jawn »

I had intended to put off a lathe purchase for a while, but there's potential for a couple good deals for a lathe purchase if I act soon.

I'm considering a couple 10" imports right now, the Grizzly G0602 vs the Precision Matthews PM1020G. Similar size, but the PM includes a stand. There are some other major feature differences though.

PM: quick change spindle speeds, 15 quick change threads/feeds, slightly lower minimum speed, power cross-feed. It looks like there are 15 metric and 10 inch threads (mostly oddballs).

Griz: Belt changes for speed changes, only 9 quick change threads/feeds, higher top speed, no power cross feed, but much more comprehensive threading abilities - 26 metric threads and 33 inch threads.

I like that the PM has the quick change spindle speed and power cross feed, but would that be worth giving up the comprehensive threading ability of the Grizzly? No idea if there's a way to re-arrange gears or add gears to add additional threading ability. Also, I googled around and I don't see much in the way of users of the PM1020G whereas it seems like everyone and his brother on the internet has a G0602.

Which way would you suggest going?
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ctwo
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by ctwo »

I'm not familiar with either machine, but when I was looking for a lathe in that size, I explicitly wanted power cross feed, and I use it quite often.
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SteveM
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by SteveM »

You can probably make a power crossfeed with a power screwdriver.

If the lathe can't thread the threads you want/need, there's nothing you can do about it.

As to a stand, you can pick up an old metal desk (the kind you see on old government offices), raise it up on some blocks and have a great stand with storage for a few bucks.

Steve
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juiceclone
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by juiceclone »

Hi
I did some hunting in that direction several years ago. I noticed that a lot of the lathes sold in the US seemed to look suspiciously similar. I found they are made by a Shanghai company called Sumore tools.
http://www.sumore.com/products_show.asp?/304.html link will take you to one with cross feed and other stuff. I bought that lathe with a mill attached to it "3 in 1" and have no complaints.
http://www.sumore.com/products_show.asp?/235.html
However, no one seems to import these models, only less capable ones. I had to import it myself which was NO fun at all. They will only sell in quantities of 5 or more, so you have to dance with them online a while to convince them to add your request to someone else's order when available.
Anyway, take a look at them ...Maybe you know someone who does import and can handle this.
wrmiller19
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by wrmiller19 »

Depends on which is more important to you, i.e. which will you use more often? As someone above stated, you can always add a power cross feed: A stepper motor is my preferred method, but it is much more difficult to add threading capability.

Which will you use the most?
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wsippola
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by wsippola »

From your description alone, I'd lean towards the PM. If I'm reading correctly, the Grizzly has a 9 selection gearbox for threads, and then uses change gears to get additional ranges. Sounds like the PM may or may not. Adding additional change gears on the PM to extend it's threading range is most likely easier than adding the crossfeed to the Grizz. And you have the slower spindle speed and stand, both plusses. You'll need to do a little math to figure out what different gears you would need to make / purchase to extend the threading range.

Check if the PM uses a metric leadscrew - sounds like it does, which is why the TPI's are mostly oddball. You may or may not want that...
Jawn
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by Jawn »

The opportunity for the better price on the PM has passed. Plus I didn't get a response from PM about what threading it's capable of, and if extra gears were available.

Leaning hard towards the G0602 now. I have a 10% off coupon expiring in a few weeks, so I may do something soon.
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Falcon67
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by Falcon67 »

>As to a stand, you can pick up an old metal desk (the kind you see on old government offices), raise it up on some blocks and have a great stand with storage for a few bucks.

Steelcase/"Tanker" desk - they are now going for big bucks. Nostalgia pricing kicked in a while back. You might still get lucky, but probably not if one is in good condition.
https://www.etsy.com/listing/155013768/ ... 7AodGyIAig
Chris -
http://raceabilene.com/kelly/hotrod
"Check all parts for proper condition before operation; if normal safety precautions are noticed carefully, this machine can provide you withstanding of accurate service."
Jawn
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by Jawn »

Falcon67 wrote:>As to a stand, you can pick up an old metal desk (the kind you see on old government offices), raise it up on some blocks and have a great stand with storage for a few bucks.

Steelcase/"Tanker" desk - they are now going for big bucks. Nostalgia pricing kicked in a while back. You might still get lucky, but probably not if one is in good condition.
https://www.etsy.com/listing/155013768/ ... 7AodGyIAig

Dang! I remember seeing those at an auction in the '90s and they were having a hard time getting more than a few bucks for them.

If I end up building a stand, I was thinking something along these lines:
http://gordsgarage.files.wordpress.com/ ... ock-up.jpg
Would be good welding practice (very much needed too!)

I have a 10-drawer 42" International box similar to that. A little beat up, but functional. I have no qualms against cutting the lid off to put it in such a stand/bench.
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Falcon67
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by Falcon67 »

Excellent idea IMHO. To your original Q - I would go for threading vs power cross, but having power cross would be pretty handy. I just used my Griz coupon today for some stuff to outfit the new lathe. It was not all cheaper than CDCO, but it nearly knocked off the shipping cost which was less than CDCO. Close enough to a wash I think.
Chris -
http://raceabilene.com/kelly/hotrod
"Check all parts for proper condition before operation; if normal safety precautions are noticed carefully, this machine can provide you withstanding of accurate service."
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Rex
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by Rex »

My bottom line these days is:

1 - No change gears, all threads use the QCGB
2 - Separate feed shaft for cross and longitudinal feed. This is the smooth shaft below the Acme leadscrew

AFAIK only lathes 12" and up meet both criteria.
There are some older 10x24 Enco lathes that meet these specs, but they quit making them about 1998 or so. Pity.
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Harold_V
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Re: Choosing a lathe - power cross feed vs comprehensive thr

Post by Harold_V »

Rex wrote:2 - Separate feed shaft for cross and longitudinal feed. This is the smooth shaft below the Acme leadscrew
While I share your concern in regards to the separate feed shaft, machines with the keyed lead screw do offer feed without using the thread of the screw, so I'd certainly include them in my search criteria. Not as good as the separate shaft, but light years better than using the half nuts.

Harold
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