Home Model Engine Machinist > The Tools and Tips > Tools > Tips on selecting a lathe -will it thread
Reply
 
LinkBack Thread Tools Display Modes
Old 02-11-2013, 01:26 AM   #31
Tin Falcon
Administrator
HMEM_ADMIN.png
 
Tin Falcon's Avatar
 
Join Date: Jul 2007
Location: down Jersey USA
Posts: 6,641
Liked 625 Times on 504 Posts
Likes Given: 18

Default Tool holding

A lathe accessory that gets lots of discussion is the quick change tool holder.
Likely the most popular is the aloris wedge style . there are many companies making these in various quality points and price points. Aloris brand while being the standard for quality is a bit pricey for the hobbyist. the piston style works but I have heard of complaints with them.
IMHO a QCTP is a must have and almost always used accessory for the lathe. they save lots of time and hassle in comparison to other toll holders. there are better QC tool holders but again pricey.
Tin



__________________

Ad maiorem dei gloriam - Ad vitam paramus
Amat victoria praeparatio diligens

Tin Falcon is offline  
 
Reply With Quote Quick reply to this message
Old 02-20-2013, 12:36 PM   #32
ConductorX
 
ConductorX's Avatar
 
Join Date: Mar 2012
Posts: 120
Liked 34 Times on 26 Posts
Likes Given: 181

Default

I have a question that more than likely everyone already knows. What the fuzzy is a Turret Lathe and how does it differ from the run of the mill everyday lathe. I found a place here in Louisiana that has a variety of old machine tools for sale. Craigslist seems to have still more.

Among them:
Southbend Precision Lathe 12" x 42" with taper attachment, collet draw bar and 3 jaw chuck. Cat No: CL8145C

LOGAN TURRET LATHE - Logan Engineering Co. Turret Lathe, model 825. Q C Gear box, 24" center distance, 43" bed length, 1 1/2 - 8 x #3 MT Spindle nose, 25/32 Spindle bore, Std. Tailstock, flat bed, cabinet, 830 Lbs. Screw turret gears.

The wildest looking thing (and cheapest) was the Rivett Model 112 Lathe. No information, but it looks like a drill press laying on it's back.

I appreciate your time and patience.
"G"



__________________

ConductorX

The Kafer Werks Shop: http://bugwerks.blogspot.com/

ConductorX is offline  
 
Reply With Quote Quick reply to this message
Old 02-21-2013, 10:41 PM   #33
Tin Falcon
Administrator
HMEM_ADMIN.png
 
Tin Falcon's Avatar
 
Join Date: Jul 2007
Location: down Jersey USA
Posts: 6,641
Liked 625 Times on 504 Posts
Likes Given: 18

Default

A turret or capstan lathe has a tail stock that holds multiple tools and rotates . it uses special tooling . it is typically set up for production or multiple part work. the beauty is once set up you can make the same part over and over all day with the pull of a couple of levers . you can make screws bolts hat bushings etc.

rivet lathes are real nice machines.
as are south bends . but remeber with old machines CONDITION unless you are planning on a rebuild, but then you still need good bones.
Tin

__________________

Ad maiorem dei gloriam - Ad vitam paramus
Amat victoria praeparatio diligens

Tin Falcon is offline  
 
Reply With Quote Quick reply to this message
Old 02-27-2013, 03:51 AM   #34
Hopefuldave
 
Join Date: Jun 2010
Posts: 36
Liked 5 Times on 5 Posts
Likes Given: 14

Default

I've always known it as a 'drive centre', never used on in metalworking but they're common in woodturning.

Dave H. (the other one)
__________________
Hopefuldave is offline  
 
Reply With Quote Quick reply to this message
Old 02-27-2013, 04:10 AM   #35
Hopefuldave
 
Join Date: Jun 2010
Posts: 36
Liked 5 Times on 5 Posts
Likes Given: 14

Default

One topic that hasn't been touched on so far, metric vs inch leadscrew: pick the threading system you're likely to cut most, as thread indicator dials only work in their native units! An inch leadscrew will (unless you have a single-tooth clutch leadscrew reverse - see the thread "screwcutting simplified") mean metric threads have to be cut by stopping and reversing after each pass with the half-nuts engaged, or vices versa. Not too bad once you get used to it but a hassle on long threads.

Dave H. (the other one)

__________________
Hopefuldave is offline  
 
Reply With Quote Quick reply to this message
Old 03-03-2013, 01:24 PM   #36
Tin Falcon
Administrator
HMEM_ADMIN.png
 
Tin Falcon's Avatar
 
Join Date: Jul 2007
Location: down Jersey USA
Posts: 6,641
Liked 625 Times on 504 Posts
Likes Given: 18

Default

Good point dave . I did touch on this in the first post.

Quote:
Metric vs imperial most lathes I have seen are either designed to measure and function and are built either to be a metric machine or a imperial machine. the difference is the lead and feed screws are made to either metric or imperial standards. so if one has an imperial standard machine and wants to thread you need a transposition gear of 127 teeth or in the case of the 7 x mini lathes a 21 tooth gear. and this gives a close approximation.

So the lesson here if wanting to do serious threading get a lathe built for what you work with or are comfortable with. some machines are built metric and only approximate us decimal inches. The newer imports have corrected this and use inch based screws.
I know a LOT to read through.
Tin
__________________

Ad maiorem dei gloriam - Ad vitam paramus
Amat victoria praeparatio diligens

Tin Falcon is offline  
 
Reply With Quote Quick reply to this message
Old 03-22-2013, 10:50 AM   #37
Tin Falcon
Administrator
HMEM_ADMIN.png
 
Tin Falcon's Avatar
 
Join Date: Jul 2007
Location: down Jersey USA
Posts: 6,641
Liked 625 Times on 504 Posts
Likes Given: 18

Default Tapers and taper attachment.

One basic lathe operation and accessory I neglected to mention earlier is tapers and a taper attachment.
there are three ways to cut a taper on a lathe.
1) using the compound.
2) tail stock offset.
3) taper attachment.
And with modern cnc there is a fourth just program in a taper.

there are plans out there to make taper attachments even for the 7 x10 lathes.

adjustable ofset centers can also be made to ease with the tail stock offset method . IIRC plans in appendix of the elmers engines book.

More late
Tin

__________________

Ad maiorem dei gloriam - Ad vitam paramus
Amat victoria praeparatio diligens

Tin Falcon is offline  
 
Reply With Quote Quick reply to this message
Old 03-23-2013, 01:10 PM   #38
Tin Falcon
Administrator
HMEM_ADMIN.png
 
Tin Falcon's Avatar
 
Join Date: Jul 2007
Location: down Jersey USA
Posts: 6,641
Liked 625 Times on 504 Posts
Likes Given: 18

Default Tool post grinder.

another accessory sometimes asked about and used is the tool-post grinder. as the name implies it is mounted to the tool post of a lathe . actualy it temporarily replaces the regular tool post. and instead of removing metal by cutting with a lathe tool the metal is removed by a spinning grinding wheel.

Like any other lathe accessory these com in various sizes price points etc. Entry level import grinders are about $150 for the single speed model and a little more variable speed.

Grinding is just another method of metal removal.
it is mostly considered a finish operation in other words machine in this case turn a part to a few thousands oversize then finish with a grinder.
so why grind?
grinding allows you to work hard materials , like cutting tools hardened centers. hardened crankshafts.etc...


grinding allows for a better finish. a better finish is desired for things like shafts and lathe centers . a smooth finish does not wear as much against a bearing.

grinding takes small bites so careful control will allow for tighter tolerances.

typical lathe tolerances are in thousands of an inch grinding tolerances in ten thousands of an inch. just make sure your mics read in tenths. hope this helps.
tin
__________________

__________________

Ad maiorem dei gloriam - Ad vitam paramus
Amat victoria praeparatio diligens

Tin Falcon is offline  
 
Reply With Quote Quick reply to this message
Old 03-23-2013, 03:12 PM   #39
Hopefuldave
 
Join Date: Jun 2010
Posts: 36
Liked 5 Times on 5 Posts
Likes Given: 14

Default

RE toolpost grinding on the lathe, a little tip:

If the grinder can be mounted on the topslide (compound slide in the USA), swivel the slide around until it's almost parallel to the lathe spindle axis - if the angle between axis and topslide is 5.74 degrees (as accurately as you can set it, 5.75 is close enough ) there is a 10:1 ratio between the topslide movement and diameter, so advancing the topslide 0.001" will take off 0.0001", allowing you a bit more control over grinding depth. Grinding cuts should be of the order of "tenths", not thou", it's a finishing process, not a roughing process

Another tip: *cover the ways!* The grinding dust is incredibly destructive to machines, being a mix of fine metal dust and abrasive particles - I've used oily cloth (with a fire extinguisher handy) and a "hood" in line with the sparks, attached to my workshop vacuum, to try to keep the dust under control. I still need to go over the lathe afterwards in minute detail with a soft brush and vacuum though! Look at the hoods fitted to surface grinders for a few hints.

Yet another tip - it's good practice (and very much safer) for the work and grinding wheel to meet "head on", it prevents the wheel hogging into the work - and gives a better finish.

If the wheel and work are moving in the same direction and there's the slightest slack in the setup, the wheel and part will try to close up, possibly bursting the wheel; head-on they force themselves apart removing the load: a burst wheel is a bit like a grenade, but harder to remove the shrapnel, being non-magnetic`.

If your lathe doesn't run in reverse, the wheel wants to be running *anti-clockwise* for external grinding, *clockwise* for internal, both viewed from the tailstock. If it runs in reverse, grinder clockwise for both internal and external, and reverse the spindle for external grinding only, normal forward rotation for internal grinding. If concerned about a screw-on chuck loosening, don't be - the loads in grinding are much, much lower than cutting loads! Belt and braces would be a drawbar through the lathe spindle, pulling on a "spider" against the chuck face, but not likely to be necessary, I'd think.

Just my ha'pennorth,
Dave H. (the other one)

__________________

Last edited by Hopefuldave; 03-23-2013 at 03:22 PM.
Hopefuldave is offline  
 
Reply With Quote Quick reply to this message
Old 03-24-2013, 01:22 AM   #40
Wizard69
 
Join Date: Mar 2013
Posts: 404
Liked 68 Times on 66 Posts

Default

Quote:
Originally Posted by Tin Falcon View Post
Those numbers you give are but one consideration. What is better a green lathe or a red. HMM
what size are the lathes how do you change the threading gears. ....
you need to look at the details when selecting a lathe but you can not forget the big picture.
What size engines are you planning on building ?
I see this as critical, if the lathe isn't sized right for the jobs you expect to do you will end up frustrated. People often buy too small and end up upgrading. On the flip side some lathes end up being bigger than they should be.
Quote:
do you need to do a 72 pitch imperial thread or a .25mm metric or will a the 56/.5 do .
there are many factors and trade offs to consider and ultimately you need to decide what is best for you. Yes we can help.
Tin
This highlights one problem for beginners, that is not knowing what they need. One thing to consider is that some lathes are easier to adapt for odd pitches than others. Given a little ingenuity and maybe a few more gears almost any pitch can be achieve. Well within the mechanical ability of the lathe to support that odd pitch.


__________________
Wizard69 is offline  
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Selecting a first engine to build. Tin Falcon About Home Model Engine Machinist 5 01-19-2014 02:57 PM
Selecting Tungsten Carbide Turning Inserts for a Small Manual Lathe (Long) quinette7 The Specialist 18 07-09-2013 08:28 AM
Selecting End Mills for a Newbee Ageless Questions and Answers 6 01-20-2010 02:42 PM
taig tips/setup Speedy's ultimate help wanted thread. Speedy Questions and Answers 62 08-05-2009 11:14 PM
Lathe tips applescotty Links 2 06-07-2008 12:11 AM




- Top - Member List