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pwilson1204
03-28-2007, 06:36 AM
Hello:

I am still contemplating reentering the hobby machinist arena (many years ago had a Sherline mini lathe and separate milling machine), and I am comparing various lathe and milling combinations, like the Grizzly G0516 combination machine. I realize the combination paradigm's limitations and may actually decide on separate machines instead.

Ergo, my question. How important is left hand threading capability in the modern (Loctite) world? The 9X20 lathes (even Grizzly's new one) cannot (per Grizzly) cut LH threads without machine modifications. The G0516 combination machine reportedly (owner's manual) can do LH threads, but only has twelve pitches available. It seems like a 9X20 and a mini milling machine might be the way to go, but I would hate to get set up and find LH threading a major lack.

So, any wise thoughts on how important LH threading is?

Thanks.

Best regards,



pwilson1204

Evan
03-28-2007, 07:09 AM
It isn't needed often but when it is needed it is essential. The only options are making on a lathe or tap and die. You can't whittle them with a pocket knife. The few times I have needed LH threading not having that capability would have been a show stopper. I should say that I do some fairly advanced work and push my lathe to the limits in terms of what it can be made to do. Not everyone will need LH threading capability.

Mcgyver
03-28-2007, 07:11 AM
I guess it depends on what you make, I did some a few weeks ago but it was the first time in many years that i'd needed them - a very infrequent activity in my shop. Also, in standard sizes taps and dies are readily available.

Todd Tolhurst
03-28-2007, 07:13 AM
Adding a tumbler reverse to these lathes is a pretty common modification, should you ever need it.

http://www.bedair.org/Tumble/Tumble.html

Bill Pace
03-28-2007, 07:54 AM
Adding a tumbler reverse to these lathes is a pretty common modification, should you ever need it.

http://www.bedair.org/Tumble/Tumble.html


This whole website, (Steve Bedairs) and its links, should give you vast source of information on this size of lathe.... and its HUGE following...

I did the tumbler reverse mod to my ENCO (along with most all the other MANY out there) and its a relatively simple effective way to get reverse feed on this lathe

madman
03-28-2007, 07:58 AM
I have built some L/H Lubow Grooved winch drums for the Winch Industry in my Garage. These drums were L/H 1?2 way and R/H the other way. They came out nice primarily vbecause my lathe will run at 26 rpm. That helps a lot. Holding the 14 inch diameter pipe machining it and then the 30 inch diameter flanges taxed my garage shop and favours at a real shop to the max. But it worked out,. The nicest thing was when the customer looked at my really shiny nice grrooves and said man they look nice. I said I used my secret coolant on em. Haha.

C - ROSS
03-28-2007, 08:40 AM
I use my equipment for both hobby and also ranch equipment repair. Left hand threading capability is essential. Absolutely could not do without it.

Ross

SGW
03-28-2007, 08:56 AM
It's not just left-hand threads.

There is also the occasional convenience of power feed to the right. Mostly you'll never do it, but once in a while it may be handy.

Evan
03-28-2007, 12:07 PM
I use right power feed frequently as I have the leadscrew driven by a speed controlled electric motor as well as the change gears. All I need do is flip a switch.

Alistair Hosie
03-28-2007, 12:16 PM
My lathe does this with lever operation all built in. It also reverses direction with the aid of a push button can't believe this could not be adapted to most lathes to do this Alistair

darryl
03-29-2007, 01:38 AM
I upgraded to an 8x18 years ago now. One of the first things I wanted to do was make a better leadscrew for the crosslide. Left hand thread. One of the first projects I did on that lathe was rig up another idler shaft to put one of the gears on to get left hand capability.

LarryinLV
03-29-2007, 02:56 PM
It's commonly held that the current crop of 9x20's on the market today need some modifications but can be made into very capable machines, including left hand threading.

One is strengthening of the cross slide for rigidity.

Another is the addition of a tumbler reverse.

The 9x20 has a strong following and specs for these modifications (as well as many others) can be found readily. One source is over on the Yahoo Groups site for 9x20's.

If I did not already have a couple of lathes; space and cost were an issue, I would consider one of these and look forward to making the mods as needed.

The lathe itself can become an enjoyable and time consuming hobby/pastime.

edited because I didn't really answer your question: I think you would be happiest with separate machines as you described rather than a combination machine. Left hand threading is infrequent and not important unless you need it, however, most small jobs can be done with a few left hand taps and dies purchased when needed.

Fasttrack
03-29-2007, 06:40 PM
I haven't cut many threads, but at least 40% of them have been left-hand threads. Without the lathe, it would have been a headache since they were wierd sizes, like 1"-18tpi left hand. Never looked, but i dont think i'd find a 1-18 left-hand die.

LastOldDog
03-29-2007, 08:38 PM
I upgraded to an 8x18 years ago now. One of the first things I wanted to do was make a better leadscrew for the crosslide. Left hand thread. One of the first projects I did on that lathe was rig up another idler shaft to put one of the gears on to get left hand capability.

For the Chinese 9x20 group, substitute the 120t gear with two smaller gears on the banjo. One additional gear in the train reverses the leadscrew. It can be done with the standard supplied gears but you need an additional "T" head shaft to mount this gear, about $2.50 from Grizzly. A little extra time, but easier than making a tumbler reverse for an occasional use. Lloyd

Edit: The reference above to the 120t gear should read 120t/127t gear set. The 2 gear idler set is removed and replaced with two smaller gears in the same plane, reversing the rotation of the QCGB input shaft.

Note: This applies to threading wherein the 120/127 translation (Imperial/Metric) is not needed.

S_J_H
03-29-2007, 11:24 PM
I have a bunch of totally unorganized pics of mods I have made to my Grizzly 9x20 that no sane person would bother with, including a reverse tumbler, 2:1 geared reduction cross slide, modified 7x compound conversion, 1hp 3ph vfd, twin belted low range, worm drive bearing mods, etc.
http://s109.photobucket.com/albums/n48/S_J_H/?start=all
The 9x20 imports can be made to work nice. But so could a tomato with enough extra iron and work.
But I had fun improving it.
Steve

TGTool
03-29-2007, 11:53 PM
Very nice mods. Nice ideas and nice work.

Jan

pwilson1204
04-09-2007, 09:13 AM
For the Chinese 9x20 group, substitute the 120t gear with two smaller gears on the banjo. One additional gear in the train reverses the leadscrew. It can be done with the standard supplied gears but you need an additional "T" head shaft to mount this gear, about $2.50 from Grizzly. A little extra time, but easier than making a tumbler reverse for an occasional use. Lloyd

Hello, LastOldDog:

I really appreciate your answering my lefthand threading question, and your 120t gear to two gears solution seems to be the easiest course of action. I looked closely at the Grizzly 9X20 manual, pictures, parts breakouts, etc., and I must be a little slow. Do you have any pictures of your 120t gear solution, or could you point me to a source? From what I can decipher, the 120t gear is in front of the 127t gear. I just can't picture how two gears here would work.

Thanks again for your patience and any guidance you can offer.

Best regards,

pwilson1204