Wadkin PK Crown Guard.

I was looking at a photo of Auscab's crown guard column - the column with the crank handle at the top to raise/lower the crown guard.

It seemed odd - or at least the mounting hole at the bottom seemed odd.

Attachment 494718 Auscab's column (PK 1857 of 1956).

Odd? Yes it's ~9/16" or so diameter. The column is held on by two 1/2" BSW (12tpi) bolts. One goes through the hole, the other in the curved slot (to allow the guard to be pivoted clear of the saw blade). So a ~9/16" hole would be appropriate - but I'm used to the massive hole in mine. 7/8" diameter to be precise.

Attachment 494720 My column (PKA 800 of 1945).
So I searched and found a restoration wallace did in 2019. It looks to also be ~9/16" - so I guess mine is the odd hole size :doh:.

Attachment 494719 Wallace's column (PKA 628 of 1941).

A friend offered to make me a new pin - with a 7/8" shank and a 1/2" BSW threaded end. But we had no way of machining a hex head, so we opted for a bush - with the head shaped like a Wadkin washer (turned not stamped, and with a chamfer on one edge). OD = 7/8"; ID = 1/2"; flange 1 3/8" x 5/16" thick.

Attachment 494721

Trial fit in the hole.

Attachment 494722 Attachment 494723

Remove, coat with oil, reinsert and apply bolt.

Attachment 494724

And while we were at it, a matching washer for the slotted side.

Attachment 494725

Note: the slot is 5/8" wide, which looks to be consistent over the three column bases I looked at.

One disappointing thing is: the bolt isn't OEM Wadkin and out of curiosity I measured the thread. It 1/2" 13 tpi - which means it's been tapped UNC. And I suspect that tapping out a 1/2" 12tpi hole with a 1/2" 13tpi tap is going to leave a bastardised threaded hole :C:~. It's holding so far, with no sign of impending failure.

Lucky we didn't make a new pin - with a 1/2" BSW 12 tpi thread !!

Cheers, Vann.

Nice fix Vann .
The older BSW English bolts are a lot nicer than the new stuff we get to choose from now at hardware stores aren't they .
There's about an extra 30% more meat to the head with some of them .
I remade a set screw for the Robinson Thicky the other day by re heating and hammering out a bolt head square then grinding . worked well . I may have to do some bolt heads too for one section of the Robinson but its a bit more involved with having to add weld .

I had a hideous time pulling the whole crown guard assemble apart. The solid shafts/steel bars were so tight on the castings it took a lot hammering (carefully and not so carefully) them through the castings. I did discover the tapered pins mind you which took my dad's 6 ton press to remove. This was by the far the hardest disassemble of parts on the saw.

Has anyone else found them parts to be so tight?
Is it supposed to be so tight? Or is it supposed to be free so you can make adjustments (can't actually see why you would want to adjust them once it's setup)?

Been awhile since I had time to do anything but did a bit of restore on mine this weekend...

Attachment 537534 Attachment 537535 Attachment 537539