Well poo. Thought I was almost done with this restoration. WIred it up and when I turned it on, with the belt engaged on the bottom wheel, it was very LOUD when it got up to speed. Decided that I was going to need to replace the bearing on the bottom wheel after all. Used my gear puller to push the shaft through the bearing and it was a little tough going. Then found out that there are 2 bearings on the bottom wheel! Should have anticipated that. Also tons of corrosion in between them.
Got a set of 4 new bearings coming from Amazon, fortunately bearings are relatively inexpensive so I’ll go ahead and replace the top wheel bearings as well. Going to be interesting resetting the double bearings on the bottom wheel. So glad I’m doing this for fun?
Bearings arrived today, boy that was quick (thank you Amazon) Installed the bearings on the lower wheel and it went so smoothly. First cleaned all mating surfaces with acetone to remove any oil residue. Then evenly heated the wheel on both sides with my heat gun, Al has about a 2x greater linear thermal expansion coefficient over steel. When it was relatively hot to the touch I inserted the bearings on both sides and they just dropped right in with almost no effort. Waited a few minutes for the wheel to transfer some of it’s excess heat to the bearings and then inserted the axle with, again, almost no effort. Let everything cool and it was lock together tight. Spins so smoothly now. Repeated for the top wheel.
One of the last things I need to do is to recreate the table tilt adjustment knob. I had made the grip part of the knob in a previous post above. Below is a picture of the knob from my bandsaw. Making the knob in 3 parts: grip end, middle and gear end.
Created the gear vector outline using the free web app that @HalfNormal had mentioned in another post. Laser cut the gear from 1/8" ply and glued 3 gears together to get the thickness i needed. Making the gear from 3 layers allowed me to minimise the effect of focal point spread of the laser cut. Also allowed me to rotate each layer 90deg, grain wise, to the previous one for added strength.
The middle stepped section I turned on my lathe from a piece of maple. Drilled the appropriate holes in the end and middle pieces and glued everything together. Finished with some wipe on poly.
The attaching bolt has a spring that goes inside the knob that allows you to disengage the knob from the table to make big course adjustments. So hopefully the gears will hold up for just doing fine adjustments.
I would say a VERY good match.
Do you think those wood gears will wear ok?
If not, You can coat the gear faces in CA or maybe make the gears from acrylic.
I did your suggestion of CA on the gear teeth. Did a couple of coats with a thin CA so it would soak in good. The teeth definitely feel harder, by the thumbnail test, so hopefully that will increase the lifespan of the teeth. Thanks again for the suggestion.
The last thing I need to do, fingers crossed, is to fix the broken bottom door latch. The plastic hinge points had broken off.
I didn’t have much confidence that I could recreate the hinge points on the plastic door and have it be robust. One option would have been to create a similar type internal latching system from 1/8" ply. After thinking about it for a bit I decided I could probably do it, but it would be fiddly to get right and would have numerous potential points of failure. Another option would be an external latching system, which would, theoretically, be much easier to do and probably more robust. This last option is what I decided to do.
The design I did was a basic swinging arm latch. The arm would pivot from the door side and latch onto a post on the body side. I found some aluminium binding posts, which are basically long chicago screws, to be the pivot point and the latching post. The parts are laser cut from 1/8" ply. I also cut a couple of PTFE washers to sandwich the arm to prevent wear.