FILENAMES: turret-tap.jpg turret-box1.jpg turret-box2.jpg turret-centre.jpg turret-die.jpg turret-drill.jpg turret-part.jpg DESCRIPTION: These are pictures illustrating usage of lathe turret tooling. Posted by Tim Leech . Tim provided the following description: ================================================================= The JPG files 'turret-**.jpg' show the setup for making a batch of gland nuts from 7/8" hex brass. They are for fuel sprayers on an obsolete Swedish 'hot-bulb' oil engine. They are threaded externally .580" x 26tpi, and internally .385" x 26 tpi. 'turret-centre' is centring and countersinking the end of the bar. The countersink in the finished product serves to compress the gland packing towards the spindle. 'turret-drill' is the tapping drill, with the depth set to midway along the parting tool so that the centring drill starts afresh on the next piece. 'turret-tap' is a commercial 3/8" x 26 tpi tap held in a drill chuck. A proper turret arrangement would use a tap holder which disengages at a preset depth, and re-engages when the machine is reversed. Not having one of these, I had to rely on a good reaction on the reversing switch when the tap was reaching full depth. (No, I didn't break any taps ) The threads were completed with a home-made tap to the .385 diameter after parting off. 'turret-box 1&2' show the box turning tool used for brass - roller boxes as used on steel aren't satisfactory on brass, so hardened Vee-guides are used in place of the rollers. This tool reduces the diameter to that for the external thread. 'turret-die' shows the .580" x 26 thread being cut with 9/16" chasers in a 3/4" Coventry die head. The non-standard size is well within the range of adjustment available on these. 'turret-part' shows the almost-complete item being parted off. I wanted to make 20 of these nuts. Improvements which might be worth trying for larger numbers might be: The box turning tool starts better if it has a small section of the right diameter to start on. A stepped parting tool, which worked to a preset depth and left a shoulder at this diameter, could be very helpful. If it was formed on the other face, so as to chamfer the corners of the nut being parted, better still. I found that the box tool would start fairly cleanly without this shoulder at 500 rpm, at lower speeds it wouldn't centre reliably. The whole operation was carried out at this speed (including the tapping). Some arrangement for drilling through sufficient to run the tap right through at one pass. I managed an average of 3/16" short of full depth, relying on the reversing switch to stop the tap. A proper tapping head with depth setting would help, but the tapping drill would still have to pass through into the next piece with the risk of losing centring over a number of pieces. Average time per piece was about two minutes, including setting to length, with a key operated chuck. I didn't have a depth stop (not enough turret positions, and not worth the time spent inventing something). What I did was to wind the centering drill right in to its stop, bring the stock up to meet it, then bring the stock up another estimated 1/4". The length of the finished product was then determined by the countersinking, as the OD of the centre/countersink was approximately the same as the thread diameter. A depth stop and lever-operated chuck would make the job significantly quicker, important if the numbers needed were into the hundreds Next job is to make some new spindles!