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High Precision Bores and Finish Grinding

Working for an international OEM supplier of the world’s most accurate precision rifle barrels. 

Brief: 

  1. Outer diameter clamping to grind bores in high precision bolt carriers for modern sport rifles.  
  2. Inner diameter clamping for finish grinding the outer diameter. 

Challenge: 

The two challenges are:

  1. Accommodating the extended part length
  2. Completing a second finish grinding step without damaging the first
Sport Rifle Bolt Carrier Grinding Group
Sport Rifle Bolt Carrier Grinding Group

Northfield Solution: 

The first operation involves grinding a bore to finish size. This bore houses the critical components that allow the firearm to function properly. 

We built a Northfield Model 620 Sliding Jaw Chuck with an extended air cylinder housing. This accommodates the long part length. The hardened and ground top jaws clamp on the rough outer diameter of the customer’s part.  

Custom Northfield 620 Air Chuck
Custom Northfield 620 Air Chuck

During loading, the part is set down on a hardened and ground axial locator, ensuring an accurate datum location each time.  

Secondly, this customer also requires work holding for finish grinding the outer diameter of the part. that they clamped on using the model 620 sliding jaw chuck in the first step.  

Custom Northfield Collet Chuck
Custom Northfield Collet Chuck

We achieved this with a custom internal grip collet chuck with a collet diameter of .5232in. This chuck clamps on the finished inner diameter while the other end is supported with a center. The operation grinds the whole outer diameter of the part, producing an accurate O.D. dimension. This ground diameter is one of the most critical dimensions required for the firearm to function reliably.  

 

Do you have a multi-step machining process that requires high precision work holding? Then get in touch.  

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Turbine Grinding Workholding

Our customer designs and sells grinding and super abrasive machining systems specifically for a variety of applications and industries. 

Brief

The operation is to grind the outer diameter of the turbine’s fins, to ensure ultra-accurate clearance within the turbo housing, due to its efficiency requirements. 

Challenge

The work holding chuck needs to hold the long shaft of this turbine and to grip the grooved diameter underneath its head. 

Grinding Turbine Custom Chuck
Custom Turbine Grinding Chuck with Part

Solution

Our solution is a  5” Diaphragm Chuck (Northfield DPH-500) Especially customized. In addition, to the brief the chuck has a spring-loaded carbide center, down in the bore of the chuck. This initially centers the part upon loading. 

Do you want to know more or have a similar challenge of your own. Get in touch with the team 

Contact Northfield – Northfield 

Or call: (516) 431-1112 

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The Top Brass – Custom Brass Top Tooling

Brief

A CNC and process automation customer required custom work holding solution for Grinding the outer diameter of their unique sapphire rods.  

Challenge

The main challenge for the Northfield team is holding the rods well enough without damaging them or creating micro fractures in the material. Additionally, delivering the trademark repeatability and accuracy. 

Custom Workholding Total Indicator Reading
Brass Work Holding – Total Indicator Reading

Solution

The work holding solution is a Northfield model DPH-400, with custom Brass Work Holding Jaws. The top tooling consists of three parts.  

  1. Hardened and ground sub jaws  
  2. A separate center button stop 
  3. Precision ground brass inserts mounted to the sub jaws 

This setup ensures accuracy and repeatability whilst grinding the outer diameter to the required size. 

Custom Brass Jaws Chuck
Custom Brass Jaws Chuck

The use of brass answers the customers need to hold their unique sapphire rod without damaging it. Brass chuck jaws prevent sliding and are very corrosion resistance, meaning there are also tough enough to operate in a grinding environment. 

 

Do you work with delicate or uncommon material? Get in touch and see how Northfield can support you. 

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Straight to the Point – Precision Drill Tip Manufacturing

Brief: 

This project is for an international metal cutting solutions provider. They required custom jaws that can hold various sized drill tips.  

The Challenge: 

The work holding jaws all need to have ‘vee-block’ type insert-pads to securely hold a variety of square parts with our trademark accuracy. 

Custom_Square_Drill_Bit_Tooling
Model 870 Sliding-Jaw Air Chuck (.0001 TIR) with custom ‘square’ top tooling.

Solution: 

Introducing our Model 870 Sliding-Jaw Air Chuck (.0001 TIR). This air-actuated chuck has two moving jaws for gripping the square or rectangular parts. 

The drill tips stop on the axial locator (mounted to the face of the chuck), and the Insert Pads (mounted in their sub jaws) clamp down on the outer diameter of each drill tip before grinding its shank. 

Extra Feature:

The Insert-Pad and Sub-Jaw design to allows for quick changeover between sizes. 

Does this sound like a familiar situation? Then give us a call (516) 431-1112 or fill out the form.

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Plastic Tooling - Ceramic Grinding

Brief & Challenge:

Our customer manufactures delicate ceramic rings. They need a way to carefully hold them on the outer diameter so they can grind the inner diameter. To protect the parts, they requested no metal contact points.

Custom_Ceramic_Grinding_Chuck

Solution:

We produced a 6” Diaphragm Chuck with non-metallic top tooling in contact with the customer’s part. The top tooling is made from the most abrasion-resistant plastic available and these items are easily replaceable for new ones should a future need arise.

Northfield Precision Instrument Corporation is a leader in developing custom solutions for difficult problems. Click here to get in touch.

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Northfield Pressure-LokTM Chucking System

Our recent product introduction, the Northfield Pressure-Lok TM Chucking System is an air chucking system that works without the air tubes and hoses. Video Below ⬇.

Northfield Pressure Lok Chuck
Northfield Pressure Lok Chuck

The Pressure-LokTM air chuck once charged with air pressure can hold pressure for up-to 3 weeks! Ideally implemented in machining operations that do not have access to a continuous supply of air.

The quick connect fitting is compatible with all Northfield chucks. The air pressure can be altered between 5 & 80 P.S.I. to adjust the grip force as required, improving the flexibility offered by spring clamping alone.

Northfield Pressure Lok Chuck
Our model 450 (3-Jaw) Air chuck with .0001 T.I.R.

Email sales@northfield.com to learn more.

Video