¾" 4TPI lead screw nut

Does anyone know where I could get a ¾" 4TPI lead screw nut? Outside dimensions not important, its to fit an old pillar drill, the table lift is by lead screw and it has stripped out the thread in the table carrier. Thanks

Simon

It is possible to single point a 3/4-4 thread. I used either a 5/8" or 1/2" boring bar with a very short tool bit. There was not sufficient clearance to withdraw the tool from the hole. I had to back off the cross slide a few thou and wind the tool out of work. I did it on a 13" lathe and it took many, many spring passes to finish the thread. I am not sure how well a smaller, less rigid lathe would handle the job.

Have you looked at the prices from the lead screw suppliers? It may be quicker and cost effective to buy a length of lead screw and a nut, for rise and fall does the pitch matter ? I did my lathe cross slide for sub £50 and have enough screw for three replacements. Consider going trapezoidal/metric it can be cheaper.

Thanks Chris Evans - I think I will go this route. The screw is almost exactly 1 M long, and as you say, pitch is not critical, it just has two bevel gears and a winding handle. I am tempted to go for a ball screw and lead, and an electric motor, with an up/down switch, just for fun. Also I am not certain it is an Acme thread, looks like a square thread, but its difficult to see clearly until I pull it out. And it weighs a lot!, must be > 150kg.

.

Presumably this is the drill pictured in your Album, and nicely illustrated here: **LINK**

http://lathes.co.uk/denbigh-drills-page2/

... If so, I am sure you are thinking along the right lines

MichaelG.

What a great illustration. Mine is newer than that with the motor behind the column and modern style multi-sized V pulley, but the main column and the table adjust are exactly the same.

Chinese balls screws are remarkably cheap and I have a windscreen washer motor that will probably do, I will post a photo when complete.

In fact, looking at the lathes site, mine is the K.1.A series 2 on page 2 here