How does steady rest work?

Self Centering Hydraulic Steady Rest holding Workpiece

If an individual is new to machining, steady rests are a somewhat overawing tool when it comes to machining but they’re very important tools in every type of CNC work. 

Normally when you are working with long stock, in order to provide rigidity to the workpiece, it should be close to chuck. Conversely, in some cases the piece on which machining is performed is too long and is away from the chuck. The diameter of your stock is too big such that it does not go through spindle bore. In these cases, a steady rest is mandatory. 

In some instances, the middle area of the workpiece cannot be pushed into the chuck because of finished surfaces or various other things. 

So, how can we perform machining at the end?

Here comes the role of steady rests. 

Self centering Steady rests aid in creating a zone of rigidity far away from the chuck and the machining processes can be performed in ease and accuracy without deflection. Infact, the rigidity can be created anywhere needed in a CNC machine across the job. 

How To Mount Workholding Solutions like Steady Rest?

Here is the step by step process of using a steady rest – 

  1. Steady rests are usually mounted at the bed of a CNC machine and before mounting it make sure the area is clean and does not have chips on the mounting surface. Clean the surface using a brush or air pressure. 
  2. There is a nut bolt arrangement at the bottom of steady rest which is used to mount it on the bed. 
  3. After mounting, it has a support system at the centre that can hold the workpiece. It has rollers or brass that keep the workpiece steady while rotating at higher speed. Personally, rollers are best because they produce very less friction as compared to brass. However, rollers are prone to chips, whereas in case of brass fingers this problem does not occur. 
  4. Following this, follow the old school approach to locate the centre of the workpiece. Finding the centre of the job is a daunting part and we recommend that you should use centre finder. Mark three to four lines using this tool and you are good to go. Further, the lines do not make a triangle at the centre. If they do, it means that your piece is not well rounded and needs machining. In other cases, you can also use a tailstock to find the centre. Conversely, there are some situations when you don’t want to do machining at the end of the workpiece. So, it’s better to have an elongated workpiece for the drilling centre.
  5. Subsequently, use a drill press to drill hole at the centre, if not possible with the tailstock. Mount the workpiece on the CNC machine and engage the tailstock as well. Now, rotate the workpiece and see if it is at centre or not using a 3D taster.
  6. Now use a sharp nose tool to create a little surface where the steady rest’s roller bearings touch. 
  7. Now clean again the surface, and place steady rest on the bed of the cnc or lathe machine. Next step is to tighten the bolts of the base of steady rest such that it remains tight while holding the workpiece. 
  8. Afterwards, tight the screw of roller bearings such that they come close to the marking of the workpiece. This step should be performed with care because there should be a gap of approximately 25 micron between rollers and piece as it aids in smooth rotation with less friction. Moreover, you can also put oil into it in order to lower the friction. Basically, you are balancing holding and friction in this step. 
  9. Consequently, rotate the chuck with the hand to double check that the workpiece is held well by steady rest and add oil at the contact point. As you are working, keep an eye on that area and don’t let it get dry.  
  10. Power up the lathe slowly and you are ready for machining. 

The Bottom Line

Using a steady rest in industrial application will make your machining process a lot easier and convenient. However, it is recommended that you should use self centering hydraulic steady rests as they will make the process automatic and less time consuming.

Leave a Comment

Your email address will not be published. Required fields are marked *