Canadian Airgun Forum

The #1 Community for Airguns in Canada!
It is currently Sat Jul 04, 2020 12:26 am

All times are UTC - 5 hours


The Canadian Airgun Forums are a place for people to discuss and learn about airguns and the airgunning sport in Canada. There are lots of discussions about airguns, airgun accessories, reviews, modification and repair information, airgun events, field target and free classifieds!

 

You need to register before you can post: click the register link to proceed. Before you register, please read the forum rules. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own pictures, and access many other special features. Registration is fast, simple, and absolutely free! To start viewing messages, select the forum that you want to visit from the selection below.








Post new topic Reply to topic  [ 12 posts ] 
Author Message
PostPosted: Tue May 26, 2020 6:23 pm 
Offline

Joined: Mon Aug 15, 2016 11:00 pm
Posts: 485
Question for those working with lathe and mill, are you using a metric system or a standard system? what do you usually use in measurement when turning metal parts? I read that in turning metal there is the advantage of the standard system against a metric, what is your opinion on this? does your the lathe or mill calibration comes in metric or standard?


Top
 Profile  
 
PostPosted: Tue May 26, 2020 6:42 pm 
Offline
User avatar

Joined: Fri Jan 22, 2010 1:17 pm
Posts: 2292
Location: Kingston, ON
pistolero wrote:
Question for those working with lathe and mill, are you using a metric system or a standard system? what do you usually use in measurement when turning metal parts? I read that in turning metal there is the advantage of the standard system against a metric, what is your opinion on this? does your the lathe or mill calibration comes in metric or standard?

Most older lathes and mills have analogue measurement devices, either metric or Imperial, so you're stuck using accessory instruments for measuring in the other system. Newer equipment or retrofitted equipment with digital readout can switch between the two. However, the gears are generally set up for one or the other system for cutting threads, so it's pretty hard to cut a metric thread on an Imperial lathe. YMMV.

_________________

Duke ))))----//----------==


Top
 Profile  
 
PostPosted: Tue May 26, 2020 7:06 pm 
Offline

Joined: Mon Aug 15, 2016 11:00 pm
Posts: 485
but how often do you cut thread on a lathe? do you usually use a tap and die attachment to cut thread to make it easier?


Top
 Profile  
 
PostPosted: Tue May 26, 2020 7:15 pm 
Offline
User avatar

Joined: Fri Jan 22, 2010 1:17 pm
Posts: 2292
Location: Kingston, ON
Once a year, and it depends on the size stock you need to thread. Bet you dont have a 1"-13 in your tap and die set.

_________________

Duke ))))----//----------==


Top
 Profile  
 
PostPosted: Tue May 26, 2020 8:26 pm 
Offline

Joined: Mon Aug 15, 2016 11:00 pm
Posts: 485
I only have the basic tap and die from crappy tire needed for basic repair, still collecting knowledge before diving into this rabbit hole.


Top
 Profile  
 
PostPosted: Wed May 27, 2020 10:09 am 
Offline
User avatar

Joined: Tue Jun 03, 2008 5:46 pm
Posts: 2854
Location: Canada
I work in inches and my machines are in inches. Most of the folks who send me drawings do so in metric, so I use that too, just convert it to inches. I also still use fractions and convert that to decimals. :lol:

I single point pretty much any thread 9/16" and up, but have done as small as 3/16-32...which is not the same as 10-32 lol.

PS...piece of cake to cut a metric thread on an inch lathe...just keep the half nut engaged. You have to stop the lathe, pull out from the cut then run lathe in reverse to get back to the starting point. Not really hard at all.

Re measuring tools...dial verniers for stuff that isn't critical, micrometers for stuff that has to be spot on. Telescoping bore gauges and either the calipers or mics for the id of parts.

Al


Last edited by Gippeto on Wed May 27, 2020 10:49 am, edited 2 times in total.

Top
 Profile  
 
PostPosted: Wed May 27, 2020 10:35 am 
Offline

Joined: Mon Aug 08, 2016 7:23 am
Posts: 3429
Location: Somewheres near the Atlantic
When I went to engine repair school. We only used Standard. All the measuring tools are in inches, and it is more precise. We had a guy from South Africa, go thru college, to just fail on OJT. Most of the equipment we worked on, all the bolts and fasteners were in STD. So 5/16 not 8mm, 1/2" not 13mm.

But I do like using metric when it isn't as critical to measure.


Top
 Profile  
 
PostPosted: Wed May 27, 2020 11:20 am 
Offline

Joined: Wed Apr 24, 2019 7:58 pm
Posts: 65
Location: Baden, ON
leadslinger wrote:
When I went to engine repair school. We only used Standard. All the measuring tools are in inches, and it is more precise. We had a guy from South Africa, go thru college, to just fail on OJT. Most of the equipment we worked on, all the bolts and fasteners were in STD. So 5/16 not 8mm, 1/2" not 13mm.

But I do like using metric when it isn't as critical to measure.


You kind of lost me. How is measuring in inch more accurate than metric? Any tolerance can be achieved in either measurement mode. I think you will find most auto drive train components are designed, machined and assembled using the metric system. As somebody with 30+ years of machine design experience I can work in either system but prefer metric as it is simpler.


Top
 Profile  
 
PostPosted: Wed May 27, 2020 12:13 pm 
Offline
User avatar

Joined: Fri Jan 22, 2010 1:17 pm
Posts: 2292
Location: Kingston, ON
I think what he means (should just let let leadslinger answer, :oops: ) is that most calipers and verniers have a resolution of 0.01 mm or 0.0001", and 0.01 mm is roughly 0.0004" so metric measuring device has inherently worse resolution than Imperial.

_________________

Duke ))))----//----------==


Top
 Profile  
 
PostPosted: Wed May 27, 2020 12:35 pm 
Offline

Joined: Mon Aug 08, 2016 7:23 am
Posts: 3429
Location: Somewheres near the Atlantic
Dukemeister wrote:
I think what he means (should just let let leadslinger answer, :oops: ) is that most calipers and verniers have a resolution of 0.01 mm or 0.0001", and 0.01 mm is roughly 0.0004" so metric measuring device has inherently worse resolution than Imperial.


This explains what I was trying to say. Like my MPS and my FPS chrony. F1 is more accurate in FPS because it reads tenths, where my MPS doesn't. Since there isn't any tenth or hundredths reading after the decimal. It doesn't translate to as accurate.


Top
 Profile  
 
PostPosted: Wed May 27, 2020 8:16 pm 
Offline

Joined: Mon May 26, 2014 1:08 am
Posts: 516
Location: Thunder Bay
My lathes are a 1945 Canadian made 11x48 Moody and a 1947 South Bend 9a x 36.
They are both calibrated in Imperial measurement only. Since I've been using them for 25+ years, my brain thinks in "thous" (.001") and "tens" (.0001")
Interestingly, I've probably rebarrelled over 100 center fire and rimfire actions (mainly bolt) and the only action requiring a metric thread (that I can remember!) was a mini-mark X mauser.
I make and install muzzle brakes (unlike airgun muzzle brakes that are really cocking handles). I cut the threads on the barrel with a single point cutting tool, concentric with the bore to within .001". That level of concentricity is impossible with a die. Note that the outside of the barrel is rarely concentric with the centerline of the bore! The only barrel in my experience that was spot on was a McMillan match barrel I had the pleasure to work on. The internal thread in the brake itself is cut with a tap held in the lathe. With this setup, I can keep clearances tight through the brake. The tighter the tolerance, the more gas is diverted out the sides of the brake, resulting in maximum recoil reduction. But damn they're noisy.

To answer your initial question, it really doesn't matter. Metric is easier. Either system can measure to microns if you can afford the instruments and actually need that level of accuracy. Is your machine able to make effective use of .0001"? My old southie... probably not.

Edit: even without disengaging the half nuts to reverse the carriage, you still need metric change gears to provide the correct advancement of the cutting tool in relation to the rotation of the work. Without the metric conversion gears, you can not cut metric threads on an Imperial calibrated lathe.

_________________
12 springers and a couple of pumpers.
2 lathes and lots of scrap metal.

Too soon old too late smart.


Top
 Profile  
 
PostPosted: Fri May 29, 2020 5:33 pm 
Offline
User avatar

Joined: Thu May 07, 2015 8:30 pm
Posts: 1406
Location: Eastern Townships
I use Standard (Imperial) measures since my lathe is graduated in this system. I convert the measures from metric to standard if needed, my calipers and mics are Imperial. My lathe has the metric and Imperial change gears, so I'm good for both kind of threads. It's a China-made lathe though, so the lead and slides screws are metric, in a pitch ''close enough'' to mimic an Imperial pitch for feed or manual advance.

_________________
If everything's so lovely yeah, then why don't I, why don't I, why don't I, why don't I feel lovely?


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 7 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list

Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group

phpBB SEO