# 9x30 lathe imperial threading questions



## Road_Clam (Nov 11, 2020)

I'm interested in purchasing this lathe:









						Upgraded 8.7"x 29.5" Mini Metal Lathe 1100W Metal Gear Digital Display 5 Tools  | eBay
					

Motor Power: 1.5 HP (1100W). This mini lathe is ideal for professional machinists, gun hobbyists, and model enthusiasts. Our small yet powerful lathe is compact and portable to fit onto your workbench with plenty of room to spare.



					www.ebay.com
				




Ideally i'm looking for a 8-9" swing with a 1.5" dia through hole primarily for gunsmith imperial threading of barrels and receivers. Would like to keep the cost <$1700 . I really need the weight to be below 450 lbs.  as I will need to get this lathe down into my basement and up onto a workbench. Lastly would like the minimum rpm capability either 50 or 100 rpms.     I'm having a hard time finding the ideal lathe. This lathe looks like a close match but it looks like it can't be configured to cut 16 and 24 TPI thread pitches. Does anyone know if there is gear combos available (or gears that can be 3D printed) to achieve 16 and 24 imperial pitches ? Thanks is advance !


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## mickri (Nov 11, 2020)

Little Machine Shop has an online calculator that will tell you what gears you need to cut different threads.  https://littlemachineshop.com/reference/change_gears.php
Here are two more gear calculators.  http://www.imagesalad.com/lathenovice/lathegears/lathegears.html  and https://www.k10y.com/gear-calculator-for-a-mini-lathe/
There is also a program that has been shared on the forum called Lathe Gears.  Do a search and you should find it.

I wish my lathe had a 1.5" spindle bore.  My craftsman 12x36 has a 3/4 bore so I will be doing my gunsmithing between centers.


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## Road_Clam (Nov 11, 2020)

Thanks mickri for all the helpfull info. Looks like you can come up with most any imperial pitch if you can fab some optional gears.


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## mickri (Nov 11, 2020)

You can probably buy the gears you need.  A lot of these lathes use the same gears.  I would ask the seller what other gears are available for the lathe.  And what the specs are on the gears.  The specs will give you the info you need to go shopping for the right gears.


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## matthewsx (Nov 12, 2020)

Before you pull the trigger on that eBay lathe you may want to read through this thread.









						First things first with a new lathe?
					

Been using a little Emco-Maier Compact 5 for the odd times I needed a lathe to do something, which honestly was small work and the Compact 5 did all I needed to do. I guess I have had it maybe 15 years or so, most of the time of which it has just been getting dusty. But recently I wanted to do a...




					www.hobby-machinist.com
				




Forum sponsor Precision Matthews has a very good reputation around here with lots of users to ask questions of.

And no, even though we share a name I have no connection to them, nor do I own any of their products. Just hate to see another forum member go through what @Tired&Retired went through.


John


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## Road_Clam (Nov 12, 2020)

Thanks for the heads up on the quality issues from that forum member comments duly noted. Believe my ive been researching lathes from PM and LMS ( i actually have the LMS 4198 dlx mill and totally happy with it). Lms lathes only have a .82 spindle bore, i need a bare minimum 1". Im looking at the pm1030 but now im far over budget as im not going to be using this lathe daily but more just an ocassuonal fix it lathe focusing on imperial threading. I do cnc machining for work so i have access to a Trak lathe anyways.


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## mickri (Nov 12, 2020)

My guess is that you are wanting to thread and chamber through the headstock.  This seems to be the current in vogue method for making very accurate rifles.  There is a lot to be said for chambering and threading between centers.  I have not seem any real test data comparing the two methods as it relates to the accuracy or lack there of in rifles.  If you are going to be using already profiled barrels most profiled barrels will fit in a .82 spindle bore.  If you are planning to profile the barrels you can do that between centers and then do the chambering through the headstock.

If you are willing to consider older lathes the South Bend heavy 10 has a 1 3/8" spindle bore.  You should be able to find one of these within your budget.  There are probably other makes that will also meet your requirements.  Look for 12" to 14" lathes.


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## Road_Clam (Nov 12, 2020)

mickri said:


> My guess is that you are wanting to thread and chamber through the headstock.  This seems to be the current in vogue method for making very accurate rifles.  There is a lot to be said for chambering and threading between centers.  I have not seem any real test data comparing the two methods as it relates to the accuracy or lack there of in rifles.  If you are going to be using already profiled barrels most profiled barrels will fit in a .82 spindle bore.  If you are planning to profile the barrels you can do that between centers and then do the chambering through the headstock.
> 
> If you are willing to consider older lathes the South Bend heavy 10 has a 1 3/8" spindle bore.  You should be able to find one of these within your budget.  There are probably other makes that will also meet your requirements.  Look for 12" to 14" lathes.



My primary goal is to learn barrel and action threading. Its getting very difficult to find gunsmiths as its a dying master trade. Ive learned many tricks to accurize an inaccurate lathe. I ultimately want to modify my lathe to utilize an outboard spindle spider. I wish i had the situation to house a quality older lathe but my situation is i need this lathe no greater than 500# as i need to wrestle it down my bulkhead stairs down into my basement workshop, then get it off the floor and lifted on to a steel workbench.


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## mickri (Nov 12, 2020)

What type of shooting do you do?  Unless you are at the very top echelon of competitive shooting threading and chambering between centers should be more than adequate.  It wasn't that many years ago that all barrel work was done between centers.  South Bend 9" lathes and similar small lathes have been used by many gunsmiths for threading and chambering for decades.  Gunsmithing does not require a monster lathe.

Getting a lathe down into a basement is a chore.  Taking the lathe apart really helps.  When I got my Craftsman 12x36 I took everything off that I could.  I did not have the any type of lift to help moving the lathe.  All I had was a HF furniture dolly and several boxes of varying heights.  Working by myself and lifting one end at a time I was able to get the bed and headstock out of my truck and onto the dolly.  Did the same to get the bed and headstock from the dolly up to the bench.  Then I reassembled the lathe.  I did not have to go down any stairs.  If I had to do this I would use a 4 part block and tackle with a cam cleat to control the descent of the lathe down the stairs.  Sheets of plywood for the lathe to slide on would help.

I would not focus on getting the lathe down to your basement.  I would focus on getting the best quality lathe within your budget and then figure out how to get that lathe into the basement.


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## Road_Clam (Nov 12, 2020)

mickri said:


> What type of shooting do you do?  Unless you are at the very top echelon of competitive shooting threading and chambering between centers should be more than adequate.  It wasn't that many years ago that all barrel work was done between centers.  South Bend 9" lathes and similar small lathes have been used by many gunsmiths for threading and chambering for decades.  Gunsmithing does not require a monster lathe.
> 
> Getting a lathe down into a basement is a chore.  Taking the lathe apart really helps.  When I got my Craftsman 12x36 I took everything off that I could.  I did not have the any type of lift to help moving the lathe.  All I had was a HF furniture dolly and several boxes of varying heights.  Working by myself and lifting one end at a time I was able to get the bed and headstock out of my truck and onto the dolly.  Did the same to get the bed and headstock from the dolly up to the bench.  Then I reassembled the lathe.  I did not have to go down any stairs.  If I had to do this I would use a 4 part block and tackle with a cam cleat to control the descent of the lathe down the stairs.  Sheets of plywood for the lathe to slide on would help.
> 
> I would not focus on getting the lathe down to your basement.  I would focus on getting the best quality lathe within your budget and then figure out how to get that lathe into the basement.



I belong to a gun club and I shoot High Power, vintage sniper, and some mid range F Class. Nothing super competitive, and my rigs are mostly oem stock precision rifles. I do have a couple aftermarket precision barrels, but they came with finished chambers. I would like to have the ability to thread muzzles as I have a few direct thread silencers. I guess i'm just concerned that if my asian lathe has the centers off vertically, that could be a challenging situation to correct. With a independent 4 jaw chuck, and a spindle spider you can easily adjust for runout. Just trying to visualize the worst concentricity scenario. The other issue is a lot of the gearbox lathes have a minimum speed of 100 - 150 rpm's. That's kinda fast for threading short distances utilizing a center. I would probably custom grind the centers to a tip dia that is slightly under my major dia so as to allow some runoff space. I have lathe experience but i'm no expert, i'm more of a milling guy. I don't have a lot of experience threading on a lathe.


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## mickri (Nov 12, 2020)

I am going to repeat what I said before.  Look for the highest quality lathe you can find within your budget.  If that lathe requires you to turn between centers.  So be it.  It will be much easier to learn on and work with a quality lathe than to have to rebuild, modify or do whatever to some piece of junk  that you bought just because it has a large spindle bore.

I am not saying that you should only buy old American made lathes.  If buying new buy from a reputable company that stands behind their product.  If buying used take some DI's and mag bases with you to check for run out.  A long straight edge to check for bed wear.  Look closely for anything that looks damaged.

When I bought my lathe my budget was way less then yours.  I concentrated on estate sales where they were selling off grandpa's junk.  I looked for a good year before I found my lathe only a couple of miles from my house.  Paid way more than my budget but the lathe had only been used by hobby machinists and came with every accessory in the craftsman catalog except for a taper attachment.  Some of the stuff was still new in its original boxes.

As for threading you will be threading towards the headstock.  I did a lot of practice on pvc pipe to get the process down.  Then practiced on steel.  Didn't take long to get the hang of threading.

Be patient.  You will find what works for you.


This is just my two centovos.


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## mickri (Nov 13, 2020)

Took a look on Craigslist in your area and saw several lathes that could possibly suit your needs.  This lathe stood out.  https://boston.craigslist.org/nos/tls/d/gloucester-south-bend-lathe-model-ce3455/7221739040.html.  Looks to be an estate sale.   It is a South Bend 9" Model A workshop lathe.   Comes with lots of tooling.  You can easily spend more on tooling for a lathe than the cost of the lathe.  If it is in as good of condition as it appears to be in the pictures and if the bed is long enough it would be a decent buy.


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## Road_Clam (Nov 13, 2020)

mickri said:


> Took a look on Craigslist in your area and saw several lathes that could possibly suit your needs.  This lathe stood out.  https://boston.craigslist.org/nos/tls/d/gloucester-south-bend-lathe-model-ce3455/7221739040.html.  Looks to be an estate sale.   It is a South Bend 9" Model A workshop lathe.   Comes with lots of tooling.  You can easily spend more on tooling for a lathe than the cost of the lathe.  If it is in as good of condition as it appears to be in the pictures and if the bed is long enough it would be a decent buy.



Thanks for the link, I guess you searched at the right time, i've been scouring CL for the past few months and found NOTHING as far as bench lathes. I also searched Facebook market place and mostly complete junk lathes, but  did find a couple 9" SB lathes but both looked rusted to crap and been sitting for ages. I'm hesitant to buy a fixer-upper as I know zip about south bend lathes. How's the market for finding replacement parts for these lathes ?  (I did inquire about the lathe, looks pretty clean to me )


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## mickri (Nov 13, 2020)

Replacement parts can be found on Ebay.  Here is a link to the current South Bend website.  Claims to have some parts available.  https://www.southbendlathe.com/products/catalog-numbers/9-inch-lathes.  I found this link by searching for south bend ce3455 lathe.  These lathes are very well made and when used in a home shop seem to last for ever.  But you still have check it out and ask lots of questions like anything you might buy off CL.  There are user groups for SB lathes and this forum is the best on the web for helping people out.  The people on here will bend over backwards to help you solve any problems that you might run into with a used or new lathe.


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## Road_Clam (Nov 13, 2020)

mickri said:


> Replacement parts can be found on Ebay.  Here is a link to the current South Bend website.  Claims to have some parts available.  https://www.southbendlathe.com/products/catalog-numbers/9-inch-lathes.  I found this link by searching for south bend ce3455 lathe.  These lathes are very well made and when used in a home shop seem to last for ever.  But you still have check it out and ask lots of questions like anything you might buy off CL.  There are user groups for SB lathes and this forum is the best on the web for helping people out.  The people on here will bend over backwards to help you solve any problems that you might run into with a used or new lathe.



Unfortunately if I pursue this lathe i'm going at it alone and uneducated. The guy in the ad clearly states he knows nothing about the lathe, it was an inheritance.


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## Larry$ (Nov 13, 2020)

Road Clam, Look @ Joe Pie's videos on threading. Short travels are no problem if you don't thread towards the shoulder. Now comes the problem with SB lathes, they have threaded spindles. Turning them in reverse is very risky. 
You can get almost anything down a set of stairs. Strip the lathe, bolt a wooden carriage to the bottom that fits over a plank, let it down with a come along. Raise it with a jack and blocking, bricks, old pallet parts, scrap 2x4's from a construction site, old set of encyclopedias.


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## mickri (Nov 13, 2020)

While he may not know anything about the condition of the lathe or how to operate it he should have some info on how long the deceased owned the lathe and what the deceased used it for.  I would plan on spending some time not so much to inspect the lathe but to go through everything around the lathe and demand that everything that you find be included.  Who knows what is in the drawers in the bench.  My guess is the seller just wants it gone.

That lathe is clean.  No rust to be seen and  no chips either.  Even the leather belt looks to be in good condition.  I doubt that somebody cleaned the lathe after the deceased passed away.  The cleanliness of the lathe is a good indication that it was well cared for.

And you are not alone.  The people on the forum will help you solve any problems that may arise if you decide to buy this lathe.

I think the biggest issue is if there is enough distance between centers for you to do the barrel work you want to do.  These lathes came with 4 bed lengths.  36", 42", 48" & 54".  The 48" bed is 28" between centers whereas the 54" bed is 34" between centers.  This lathe looks to have either the 48" or 54" bed.

Can't hurt to go look at it.  Let us know what you find out.


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## Road_Clam (Nov 13, 2020)

mickri said:


> While he may not know anything about the condition of the lathe or how to operate it he should have some info on how long the deceased owned the lathe and what the deceased used it for.  I would plan on spending some time not so much to inspect the lathe but to go through everything around the lathe and demand that everything that you find be included.  Who knows what is in the drawers in the bench.  My guess is the seller just wants it gone.
> 
> That lathe is clean.  No rust to be seen and  no chips either.  Even the leather belt looks to be in good condition.  I doubt that somebody cleaned the lathe after the deceased passed away.  The cleanliness of the lathe is a good indication that it was well cared for.
> 
> ...



mickri, do you know if the lathe in the CL ad uses "change gears" for threading ? Should there be a set of gears to go with this lathe?


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## mickri (Nov 13, 2020)

It has a QCGB.  The QCGB looks to be different from the OEM QCGB.  Might be an aftermarket product.  So you shouldn't need any change gears for threading.  There may be change gears tucked away in one of the drawers along with who knows what else.  I enlarged the photo's.  There are 2 keyed chucks and 2 keyless chucks.  There are a bunch of end mills.  Wouldn't be surprised if there is a milling attachment.  There is a complete set of collets.  There is a small 4 jaw chuck.  It has a QCTP and at least 5 or 6 tool holders in the pictures.  Probably more in the drawers.  Most people have 10 to 20 tool holders for their QCTP.  I have 12 for mine.

This lathe is worth going to look at.


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## Hard_ware (Jan 6, 2021)

The 8X16 or the 38mm big bore lathes will need work to get them ready to use.  The 1100w one you listed I hope they improved on the 8x16 as it needed some work to get it ready to use.  You can cut any thread pitch with the right gears. Imperial is easiest to cut on a lathe with an imperial lead screw and metric is easiest with a metric lead screw. I find it faster to cut disengage the lead screw and reset for another pass with the lathe running all the time. You *can't* do this when cutting metric on imperial or imperial on a metric. You have to Cut then stop then reverse then stop then reset for another cut. The 38mm bore lathes you need to construct a lathe spider on the pass thru side to center barrel if working on the chamber, or center the chamber when threading the barrel. Never use the outside to center a barrel, use the bore. Number40fan has some videos on youtube and has threaded several barrels with the 8x16 38mm big bore lathe. These are project lathes not ready to go purchases in my opinion. I am thinking of adding an electronic closed loop lead screw motor for turning so I can set a start point an end point and a cut and return to start point button. For cutting threads the 3d printed gears I made work perfect for me. I added a magnetic mounted Shahe DRO and a clamped mounted one with Touch DRO installed on a tablet, works awesome. You can store workspace profiles of your cuts to make repeat parts. Just line up the the x with the targets and away you go.

If you have the space best to go bigger 
I have limited space and 8x16 fit what I needed.
I started out on a 7x14 mini lathe so the 8x16 is a monster.
Many of these out there so any problems you will see have already been resolved by others before you.
Just a matter of some work to get it right.


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## Larry$ (Jan 6, 2021)

"Unfortunately if I pursue this lathe i'm going at it alone and uneducated."
Nope, you've got help right here! 
All of us started out uneducated, some less than others, I'm a prime example. 
I learn something on every project. 
I've made a lot of mistakes, does that mean I've learned a lot? No, got a long way to go.


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