Making these "stock nuts" is based on an article seen in Model Engineering Workshop, Vol. 44, pg. 20. The nuts are made to hold split nuts so a screw shaft can be held in the lathe and trimmed to length. A table with the stock nuts made and some critical parameters for their construction is shown below.
| Stock Nut | Clearance Drill | Bore Depth | Bore Diameter | Nut Diameter |
|---|---|---|---|---|
| 6-32/40 | 19 | 0.109 | 0.360 | 0.312 |
| 8-32/36 | 10 | 0.125 | 0.397 | 0.344 |
| 10-24/32 | 7/32 | 0.125 | 0.433 | 0.375 |
| 1/4-20/28 | 9/32 | 0.125 | 0.505 | 0.438 |
| 5/16-18/24 | 11/32 | 0.156 | 0.577 | 0.500 |
Three of the stock nuts were made from 5/8" hex steel bar. A 1 1/4" length was cut off with a hacksaw and one end faced in the lathe. The part was drilled through and then bored according to the dimensions given in the table starting with the smallest stock nut. The completed nut was parted off at 0.25". This process was repeated for the next two stock nuts enlarging the drilled through hole as needed.
3/4" hex stock was used for the two larger stock nuts. These were parted off at 1/4" and 3/8" for the 1/4" and 5/16" sizes respectively. The 1/4" and 5/16" nut bore depths were increased from those in the table as the standard nuts in these sizes are 0.22" and 0.27" thick. Both were bored about 0.1" deeper.
All of the stock nuts were marked, center drilled, drilled (#36), and tapped 6-32 for set screws. Matching standard nuts were slotted. The stock nuts were labeled with number punches according to their respective sizes. A block of wood was selected to function as holder for the set. Holes were drilled with Forstner bits for the stock nuts and slots were milled for the slotted nuts. Set screws were installed in the stock nuts and an Allen wrench to fit was included in the final set.
