Chapter 22.2 – Grate SupportsThe shop happening this week is the Grate Supports. A seemingly simple pair of parts, but really, there was a lot of work in these!
But before I started them I decided it was time to tram the mill. I’ve been meaning to do this for some time and before I started this part seemed like a reasonable time.
So, using my magical retirement gift, I went to work and got it all trammed up. Yay!
Then I checked the tram in the reverse direction and realized that I needed to calibrate the tramming tool. Oh no!
So, after calibrating the tool, I re-trammed the mill. And got it pretty close! Yay.
I also trammed it in the Y-direction. But to do that I had to add a little shim to the column since my mill has no ‘nod’ adjustment. If you look closely, you can see a 0.004” feeler gauge sticking in the back of the mill column. I was surprised it took this much to tram in the y-direction, but it did. And it’s pretty good now.
OK, with that excitement behind me, I started on the supports, which were cut from 1/4" x 5/8” 1018 steel. They were first taken down from 5/8” to the specified 19/32”. Odd dimension, but that’s what it calls for. Next, I stacked them together and, after trimming the ends to length, I drilled the mounting holes (which will be threaded 3-48) and the pivot hole for the ash pan (the hole on the right).
There is a support on each side – right and left. So that was about all I could do with the two parts stacked like that since they are mirror images of each other. I marked them up to help me be sure to keep their orientation straight.
First, I clamped them together, flat-wise in the mill vise, making sure they were in the correct orientation and proceeded to carve out the shelf that the grate will slide into.
And, without moving the parts, I cut a slightly deeper groove all along the top of each of the parts as indicated in the drawings. Remember, these parts are mirror images, so the top of each part is facing the middle of the vise.
Now to focus on the right support. It has a few additional features for mounting the latch and spring holder. I marked those on the part (not for accuracy, but to make sure I was putting them in the right place!) and then drilled the mounting holes.
And cut some 1/4" wide notches for these two parts (grate latch and spring holder).
The leftmost notch is for the latch and it needs some additional room so that the latch can move back and forth. Kozo shows cutting a 15
o angle on that notch. To do this, I rigged up some angle blocks to hold the part at the specified angle. Note, the part is upside down in this picture - I was holding it between my 15
o angle blocks by the skinny rail along the bottom of the part.
And clamped it in the mill vice. Then after finding the center of the notch, I proceeded to widen it to the 15
o angle.
Next, we need to cut a relief in the end where the ashpan will attach. This needed to be done at a 45
o angle. I used an angle block to set this up but then slid it out of the way after clamping to avoid damaging the angle block. The angled cut doesn’t go all the way through the part – slightly less than half. It just has to be deep enough to allow the ashpan to pivot.
And finally, to the rounding jig on the sander where I rounded the end and put the specified 25
o angle on the part.
And here are the completed grate supports:
In situ on the back of the engine, under where the firebox will eventually be.
Looks pretty grate, doesn’t it, CNR and Chris! (See, I can do it too!)
Thanks for looking in,
Kim