Manufactured during the 1950s, the very well made but rarely-found Burnerd Type TP quick-set tool holder was likely to have been offered in four sizes, Small (TP-1 for tool up to 3/16" deep), Medium (TP-2 for tools up to 3/8" deep) Larger (TP-3) for tools up to 1/2" deep and Largest (TP-4) for tools up to 5/8" deep. However, so far, only the two smaller and the largest have been found and it appears that a complete set would have consisted of a central carrying block and the following tool holders: left hand; right hand; boring bar complete with bar; "form" (including a 1-inch diameter by 1/4" thick tool blank to be ground as required); parting-off (including the cutting blade); recessing; knurling (including a floating head tool with a medium diamond knurl) and one 'blank' to be used when only one holder was mounted - as two holders needed to be in place for the unit to function correctly. Additional pictures of this unit here