Deep Drilling with the Sub-Spindle of the SV-32J/SV-20
In the process of a turnkey operation here at the Ohio Tech Center, a hole in 2011-T3 Aluminum needed to be drilled, flat/bottomed, and reamed 113mm (4.5") deep in the backside operation. The standard drill sleeve holder is offset away from the guide bushing, to allow front drilling and simultaneous operation, but at the sacrifice of available depth on the sub-spindle side of the holder. While this is desirable 99% of the time, this particular application demanded more depth than normally available in the backside operation. To meet the need, we designed and built drill sleeve holders which eliminate the offset, clearing the guide bushing face by 3mm (.118").
These holders are adapted for 6mm x 4mm copper tubing, to provide coolant through the tool. Using low-profile coolant sealing nuts from Rego-Fix, and with ER-20 collet sleeves cut to 50mm (2.0") long 'assembled' OAL, a drill projection of 120mm (4.750") can be achieved. As you can see from the picture, even more is possible - up to 133mm (5.250") without milling the face of the drill sleeve holder. This is a picture of the test drill, and was replaced by more efficient coolant-fed drill styles.
In this application, the drill is 10.7mm (.422") diameter, drilling 97mm (3.800") deep in 2011-T3 aluminum. The two coolant orifices of the drill were 1.14mm (.045") diameter each. 800 PSI coolant through the drill was achieved by the use of a 3 GPM high pressure pump.
To acquire one of these holders, or other special accessories for your Star lathe, please email us at ohio@starcnc.com, or call 440-546-1916!
