Click Here for AirGunHome.com Main Page
Argentina Australia Belgium Canada Chile Denmark France Germany Greece India
Italy Mexico New Zealand Netherlands Norway Russian Federation South Africa Spain Turkey United Kingdom United States
AirGunHome.com: THE Worldwide Airgun Forum


AirGunSeals.com Main Page Link
Air Gun Home Forum Index Register FAQ Memberlist Search

Air Gun Home Forum Index » Airgun Smithing » Shop made reamers and drills
Post new topic  Reply to topic View previous topic :: View next topic 
Shop made reamers and drills 
PostPosted: Mon Jul 02, 2012 8:59 pm Reply with quote
SMP
Silver Status Member
Silver Status Member
Joined: 04 Feb 2011
Posts: 1183
Location: Just south of "Out There"- Land O Lakes Ontario
Here you go Bob
Part one will cover making a single or multiflute reamer or a D drill.

In Part two I'll cover what I know about throats, leades, geometry and the why's and wherefores. I'm not the last word on this subject by any means. Still a lot to know I'm sure.

To start off D drills, D reams and flute reams are all basically the same thing but their final use determines how much the metal is cut away.

They are all made from tool steel bar stock either silver steel, O1, W1/2. I like to use O1 because although is is harder to machine it is very stable during the quench. Essentially silver steel is highly machineable water or oil quench medium hardness, O1 is oil quench medium/high hardness and W1,2 is water quench high hardness.
O1 is readily available from Fastenal in all sizes up to 1" and after a recent scare of not being able to find any I now keep 3' of everything in stock.

These are D reamers (the name comes from the shape of the cross section. D drills are the same but without the pilot at the tip. Typically the tip of a D drill will be ground on a 15deg angle with the point at the cutting edge. They are used to drill very accurate holes of odd sizes. much more accurately than a twist drill.
In making a D reamer/drill a bar is turned to the exact OD of the desired hole and then material is removed by milling or grinding to the centerline of the bar. 1 or 2 thou less than the centerline results in a smoother cut and better finish. 1 or 2 thou past the center line is a faster cut and lower finish.
If the material is removed by a mill it's done before hardening. If the material is removed by a grinder it's done after hardening. When these things were made every day by shops they would usually be ground.


These are single flute reamers. Again they are turned to the exact size and a flute is milled into them right on centerline or below centerline. The farther below centerline the flute is milled the more aggressive the rake will be.



This one is cut well below centerline and thus has an aggressive rake.



As it turns out I needed to make a simple ream to duplicate a crosman 7/16 barrel breech so I documented the process.

A piece of .250" O2 about 3" inches long is chuck up. I have a little runout in this new three jaw so there is a piece of shim stock just showing. I usually find that I'm cutting on the backside of the work in order to use very shallow angles on the compound. I preset my compound angle to the first angle I will encounter in this case a 2deg leade. Then I use the tool holder to adjust the tool angle. I find that setting the tool just a widgin below center and using high speeds and slow feeds gives a decent finish on O2.



O2 doesn't like a zero cut or a cut deeper than .010 or it tears.
On the first operation I turn down to the OD of the throat the full length of the throat plus the length of the pilot. Next I machine down the portion that will be the pilot (0.0005 smaller than the bore) On the last pass I bring the tool to the shoulder and switch to the compound and machine the 2deg angle for the leade






Then I back the carriage away and reset the compound to a 30 deg angle to machine a lead in angle for the Oring into the shoulder area.



The next step is to polish it to a near perfect finish. The finish on the ream determines the finish on the work.



Then it's off to the mill to machine in the cutter edge. I index off the full shaft size and then dial down to the desired depth. In this case it's only 0.0005 past center. I'm after a slow cutting reamer with very nice finish. How far too mill back is a bit of a tradeoff. Too shallow and there is no room for swarf, too depp icreases the chance that it will warp. Something less than the centerline is always safe.





Here's the finished reamer ready to harden.



Next the piece gets chucked up in the drill press warmed up with a torch and coated thoroughly in soap. I'm not sure why but it protects the metal surface from decarburizing during heating and after the quench the soap flakes off and leaves shiny metal.


Next the quench oil is heated to between 175 and 225 degF. I use canola but any vegetable oil will do. Not heating the oil can cause the piece to crack.


Then turn on the drill press at slowish revs and start heating the piece. I bring the body just above the cutter up to blood red before angling the heat to the cutter. I'm using a propane torch with MAPP gas here. If your using Oxy/Acet then a slightly rich flame is better than lean to protect against decarbonization. Once it hits cherry red(also the point where a magnet wont stick) quench it fast by emmersing the spinning part in the oil and swirling.


Here's the part right after quench. You can see the areas where the soap has blown off revealing shiny metal



Check the quench by touching a file to the body of the part. If it's well hardened the file will not cut. Polish the part as well as possible while avoiding the cutter edge. Then I lightly stone the flat that makes the cutting edge until the edge feels smooth and flat to my thumbnail.

O2 in a reamer needs to be tempered to 470deg F. This is perfectly suited for my convection microwave. A guideline is 1 hour per inch then air cool. for a small part like this I temper for 30 minutes. You can't over temper in an oven



Here is the finished reamer and a reamer crosman breech. I like to orient the pocket of the flute up to hold a puddle of cutting oil. Note that this reamer is cut to be used with the machine running in reverse.




_________________
Sean
View user's profile Send private message
 
PostPosted: Mon Jul 02, 2012 10:15 pm Reply with quote
rsterne
Moderator
Moderator
Joined: 15 Jan 2008
Posts: 2998
Location: Coalmont, BC
That is EXCELLENT.... I'm going to bookmark this page for sure.... I can't tell you how much I appreciate the knowledge and time you put into this post.... I'll certainly look forward to part 2 with the suggested dimensions....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count!
View user's profile Send private message
 
PostPosted: Tue Jul 03, 2012 9:01 am Reply with quote
radar
Silver Status Member
Silver Status Member
Joined: 13 Nov 2011
Posts: 1138
Location: Des Moines, Iowa, USA
Neato!
I'm bookmarking too.

_________________
It's never too late to have a happy childhood.
View user's profile Send private message
 
PostPosted: Wed Dec 05, 2012 1:13 pm Reply with quote
rsterne
Moderator
Moderator
Joined: 15 Jan 2008
Posts: 2998
Location: Coalmont, BC
HEY SEAN !!!

How about those "typical dimensions" for a chamber?.... Mr. Green

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count!
View user's profile Send private message
 
PostPosted: Thu Dec 06, 2012 7:45 pm Reply with quote
robert w
Senior Member
Senior Member
Joined: 12 Feb 2012
Posts: 574
Location: usa
great post there sir

_________________
,crosman 400,gamo big cat in .22, diana 5g,diana 54 air king, diana 34 in .22 diana 34 in .177, wilrauch hw-55,and a romainian pioner training rifle , and a huge collection of powder burners 35 last count . 1 would think i have a gun store
View user's profile Send private message AIM Address
 
PostPosted: Mon Dec 24, 2012 8:46 pm Reply with quote
SMP
Silver Status Member
Silver Status Member
Joined: 04 Feb 2011
Posts: 1183
Location: Just south of "Out There"- Land O Lakes Ontario
Please excuse my tardiness gentlemen.....

Still trying to figure out this baby thing Laughing

_________________
Sean
View user's profile Send private message
 
PostPosted: Mon Dec 24, 2012 8:59 pm Reply with quote
rsterne
Moderator
Moderator
Joined: 15 Jan 2008
Posts: 2998
Location: Coalmont, BC
They don't come with instruction manuals.... worse the luck!

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count!
View user's profile Send private message
Shop made reamers and drills 
  Air Gun Home Forum Index » Airgun Smithing
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 vote in polls in this forum
All times are GMT - 5 Hours  
Page 1 of 1  

  
  
 Post new topic  Reply to topic  

Note: If you are seeing "Please enter your username and password to log in." Your browser cookies have been reset
or you need to register to access the topic in question. Use the 'Register' button near the top left of this page.


Click Here for AirGunHome.com Main Page


Powered by phpBB © 2001-2004 phpBB Group
Partial Styling Supplied by Vjacheslav Trushkin Themes Database.