Double Turks Head Setup and Adjustment Instructions for a Tube or Pipe Mill
Vice President Tube Mill Engineering
Technical Advisor and Technical Service Coordinator
Purpose: Provide basic information and instruction for straightening a tube/pipe using a Double Turks Head.
There are several factors that can influence the straightness of a tube/pipe aside from the Turks Head. Let’s discuss these first before addressing the Turks Head itself.
- Make sure RPM’s are matched on multi Motor Drives. If you don’t have a digital readout on your control console, the Spindle RPM’s can be checked with a Digital Hand Tachometer and should all read the same to start out with. Typically, by design, there is progression built into the Root diameters of the roll tooling causing slight pull or tension from entry of Mill to exit. In most cases, roll tooling is reworked as an entire set so the throats are kept consistent. If sections are reworked separately and the throats are not maintained, refer to our link on our web site for calculating RPM’s of mill drives.
- Proper setup of roll tooling from Breakdowns through Sizing Passes. Refer to your Setup Charts from your tube and pipe tooling vendor for each set of tooling and ensure each Pass is doing what it’s designed to do. Refer to our links on our web site for the proper tube and pipe mill set up.
- Setting up the Breakdown Section: Can Your Tube Mill or Pipe Mill Take the Pressure?
- Setting up the Fin Section
- Setting up the Welding Section on Tube and Pipe Mill Lines
- Setting up the Sizing Section
- Misalignment of tooling, especially in the Sizing Section can have an effect on part straightness.
Distance of Turks Head Stand from the last Sizing Pass.
- The closer the Turks Head is to the last Sizing Pass, the more reactive it will be when making straightening adjustments. As the distance increases it will take more of an adjustment to achieve the same reaction.
- Make sure that the welded tube is being properly cooled before enters the Sizing Section. If the tube/pipe is still hot, it doesn’t matter how well it’s sized or straightened, it will not stay straight once it starts to cool. A good rule of thumb is the touch test. If the tube/pipe is too hot for you to place your hand on it and hold it there for a length of time, it’s too hot to straighten properly and you should look into the effectiveness of your Coolant System.
Turks Head Setup
Properly install tooling in the Turks Head Clevises.
Use a Straight Edge along the faces of the tube and pipe rolls to make sure they are in line horizontally and vertically.
Position the tube and pipe rolls.
Methods for doing so are:
- Use Feeler Gauges to check the rim clearances between all of the tube and pipe rolls. The correct rim clearance can be found on your Setup Charts. Make adjustments to the tube and pipe rolls until you’ve achieved the proper clearances all around.
- Use a Plug Gage made to the designed profile for the specific set of roll you are setting up. This is the “best” and “most” recommended method.
- Set Gauge into the bottom roll.
- Bring the top roll down until it contacts the Gauge and no light can be seen between the Gauge and the rolls.
- Adjust one of the side rolls in to see where it contacts the Gauge. If the top or bottom Roll Flange hits first, adjust the top and bottom rolls together, up or down until the profile matches and no light can be seen between the roll and the Gauge. At this point, you should simply have to adjust the remaining side roll in until it touches the Gauge. One of the advantages of using a Plug Gauge is you will eliminate any backlash in the Clevises if it exists. This can save minor adjustments later when you put material through the rolls.
Make sure rolls are perpendicular and parallel to the Mill Base.
Methods for doing so are:
- Use a Square and check from the face of the horizontal Turks Head Rolls to the top of the Mill Base.
- Use a Cross Test or Torpedo Level on the face of the rolls.
- *Note: If you have square shapes that run on the diamond orientation you will have to utilize a Square or Level with features allowing you to check a 45 degree angle.
- Make rotational adjustments as required.
Adjust the rolls to the centerline of the Mill to start.
Methods for doing so are:
- There may be a reference mark to put them on center from the original installation.
- Run a String Line or Wire through the Sizing Rolls and the Turks Head Rolls. Center it on the first and last Sizing Pass to establish Mill centerline. Adjust the Turks Head Rolls to this reference.
Adjust the rolls to the proper Pass Line.
Methods for doing so are:
- Use a straight piece of ½” Pipe or a piece of Drill Rod that will extend through your Turks Head Rolls and at least into the last (2) passes in the Sizing Section. Drop the Turks Head Rolls far enough to clear the Pipe / Drill Rod when it’s laid across the throats of the bottom Sizing Rolls. Adjust the Turks Head Rolls up until they just touch the tube/pipe / Drill Rod.
- Use the String or Wire that was used for centering instead of tube/pipe / Drill Rod as described in the last step.
- There will be a known Pass Line dimension at the last Sizing Pass that can be derived from adding the dimension from the centerline of the bottom Spindle to the Mill Base to half of the throat diameter of the bottom roll. Once this dimension is established, use a Height Gauge to set the Turks Head Rolls to the same dimension. You can also just use the Height Gauge to begin with to measure the distance from the throat of the bottom roll in the last Sizing Pass to the Mill Base.
Turks Head Adjustment
- When running “round” tube/pipe, the Turks Head rolls should not do “any” final sizing of the tube/pipe; they should only lightly ride on the tube/pipe for straightening purposes only.
- When running “squares and rectangles”, the Turks Head Rolls are many times designed to do final sizing and straightening. Set up the entry and exit Turks Head rolls per the set up chart. In order to properly check the tube size out of the entry side set of Turks head rolls, you will need to back up the mill slightly so you can measure the formation of the tube/pipe as formed by the entry set of Turks Head Rolls, for there is no way to obtain this measurement between the entry and exit face plates. In both configurations, “round and shapes”, the operators should be using the entry side of the Turks Head for straightening the tube/pipe. You are working the entry side of the Turks Head against two stationary points, the last driven Sizing Pass and the exit side of the Turks Head. This is why it is important to install the double Turks head as close as you can to the last Sizing Pass. As described above, if the distance is too great, you will have to adjust the entry side of the Turks head more to get the tube to react to the straightening adjustments. This in turn can cause a tube/pipe to continually wander, and or incur marking.
- If the tube/pipe bows up or down, use the up and down adjustment of the entry Face Plate of the Turks Head for the correction. If the Turks Head Rolls aren’t doing any work, you will adjust them “up” to remove “up” bow and “down” to remove “down” bow.
- If the tube/pipe bows left or right, use the side to side adjustment of the entry Face Plate of the Turks Head for the correction. Again, if the Turks Head Rolls aren’t doing any work, you will adjust them to the “Operator side” to remove bow to the “Operator side” and to the “Drive side” to remove bow to the “Drive Side”.
- With squares and rectangles only, use the Lead Screw for the rotation of the Entry Face Plate to correct for twist.
- If there is work being done in the Turks Head Rolls, which is common with squares and rectangles, the adjustments outlined above “will” be opposite. This is also the case for those customers that only have “one” (1) single Turks head.
- Note: Once the exit side of the Turks Head has been set up to come in line with the Pass Line and center, it should not be moved or used for straightening.
Please see our web site, www.roll-kraft.com for more technical articles and video rants on the integrity, alignment, set up, operation and trouble shooting of tube and pipe mills. Roll-Kraft also offers tube and pipe tooling as well as tube and pipe training seminars and on-site training.