Delta Jointer Screw Question?

[Scott Rychnovsky]

I am cleaning up an old Delta jointer and I want to replace missing screws that hold on the sheet-metal sides. Unfortunately, I have not been able to match it. I have enclosed a picture of the screw (right) and one of the ones I have tried as a replacement. It is listed in the diagram as a 10-32 x 5/8 screw, but that is not correct. (I have pulled more than one to check.) It appears to match threads with a 10-24 screw (left). However, the 10/24 screw does not fit in the hole--it locks after about 1/8". The thread diameter on the 10-24 screw is about 0.190", but on the Delta screw it is 0.177". It appears to be a "hex washer" screw, but the lower threads have a gap--is that some type of lock-thread adaptation? I have looked on McMaster Carr, but I am not sure of the type or size. Any advice would be appreciated.

The obvious metric screws appear to be the wrong size.

Thank you.

Scott

[Julian Tracy]

The metal is thin enough - why not simply tap a new hole one size larger to fit whatever screws you have on hand?

If you don't have taps - you can use a screw thread as a makeshift tap by filing a couple angular grooves to give the threads a cutting action.

JT

[Scott Rychnovsky]

I need two screws out of 12. I can tap two of the holes to the larger size. Then I need to use two different types of screws. I can tap all the holes and switch to new screws. Both of these are possible, but I was trying to keep it simple. I will pull out my taps if I cannot just purchase a replacement screw.

[Charles Lent]

Lowes has a plate on their bolt shelves where you can check your bolt to see what size it is. The plate contains threaded holes for all sizes including metric and I use it often. Home Depot likely has the same, but I rarely go there. The bolts in your photo show a groove in the threads, so they are designed to be self-threading. Bolts like this do not thread holes as perfectly as a tap since the thread only has to fit the bolt that is being installed so don't expect to find a perfect fit in the plate at Lowes, but you should find one that is very close to that size, at least better than the 1/8 turn fit that you had.

Charley

[Scott Rychnovsky]

I ended up tapping holes on one side (to 10-24) and replacing half the screws with new ones (shown in the picture.) It took very little time. Thank you for the explanation that the original screws were self-tapping (but they did not tap to normal dimensions.)

Scott