Die Head Universal Lock Screw Replaces RIDGID&reg; Part 39860 Fits RIDGID&reg; 811A Replaces RIDGID Part 39860 E933 Lock Screw Fits RIDGID 811A Universal Die Head. Restore the Die Head on your Ridgid Pipe Threader. PT Parts are an after-market alternative to ridgid parts. Vast selection of ridgid tool parts and Ridgid 300 parts. For best results, rebuild your die head at the same time you replace ridgid pipe dies.