depth settings, threading depth for the Tiger. Simple really to set up for best results, saving threads, tap and production.
How the Depth Stop Collar Works
The Roscamat Tiger’s depth stop collar is an adjustable depth stop located on the quill arm. When the tap reaches the pre-set depth, the machine reverses automatically. The collar is slid along the calibrated rod and locked into place with the knurled nut.
Calculate Your Required Depth First
Use your drawing dimensions to set up your part on the Roscamat Tiger. The depth for a blind hole is the depth of the hole less than 1.5 times the diameter of the tap. This must be within the normal form of the thread and must not be an undercut thread as it will not hold a fastener.
Setting the Stop for Blind Holes
Adjust the depth stop collar indicator down to the depth you require for your thread and then tighten the knurled nut as tight as possible. Check that it is still tight before commencing to drill the material, as the collar may vibrate loose and bottom out the tap.
Through Holes Are More Forgiving
Note: For through holes set the depth stop at a point where the tap will just pass through the back of the workpiece, then retract to avoid over-running. The Roscamat Tiger automatically reverses at the end of the stroke, so there is less risk of damage to the tap in through holes.
Run a Test Tap Before Production
Just as a trial hole is machined before cutting the finished article, a test tap should be used to test the newly set depth stop collar by checking the newly cut thread with a Go/No Go gauge. If the newly cut thread is too short or looks to be too thin then the collar will have to be slackened off and half a turn of collar (i.e. 1/2 turn of depth) added and then re-tightened before another test tap is cut.
Adjusting for Different Tap Lengths
Note that changing tap holders will affect the effective length of the quill arm. There is more on Roscamat Electric Tapping Machines at https://www.cotswold-machinery-sales.co.uk/roscamat-tapping-machines/electric-tapping-machines/roscamat-tiger-electric-tapping-machine/. Recheck depth stop collar setting after changing any tap holders.
Setting the depth stop for a few minutes at the beginning of a new job will be worth it to avoid the entire batch of parts being ruined when the tapped holes do not fit!