Don't know your Bore scope but has it got its' own power supply?
If not and it needs power from the USB connection, connect it to the tablet via an appropriate OTG (on the go) adapter cable.
This will enable power to be supplied from the USB port of the tablet.
Normally the tablet is a USB "Device": therefore there is no power supplied on the USB port. Using an OTG cable turns the tablet into a USB "Host" which has got power on the USB port. With an OTG cable you can now also connect flashdrives, USB keyboards (not all will work) and Mouse to the tablet.
Also to lengthen the amount of battery usage time, when using an OTG connected device, turn off the tablet's WiFi (if not needed).