Emco V13 Taper attachment build

dfloen

Active Member
#21
Its 1018. Its typical for cold rolled to do that when machining. You deal with it similar to dealing with welding warpage/shrinkage. It will be fine for what it is. If i could have found a cast iron bar the correct size for less than a first born, i would have used that for sure. Hot rolled is usually pretty good as far as stress goes too. I didn't have the right size in stock and just wanted to keep moving on this project. The next one will be all cast iron.
 
#22
Some recent progress pics


Tee slots.


Yup, I screwed up. Forgot to move over the radius of the 5/16" endmill on the second one. Dammit


Since I didn't radius cut the tee slots in the lower bar, I oblonged the slots in the upper bar. I don't think my 6" rotary table would have liked a radius cut of 6.9". New 12" Yuasa rotary table is still a week away.




Pivot pin is a hardened 0.500" dowel pin. Drilled and reamed the lower bar for a half thou press, 0.000 fit into the upper bar.

Going to grind everything to size and make the guide shoe and linkage, and a tool holder and it'll be done.
 
#23
Bit more work today


Making the slider block. Started off by slicing up some cast iron from a tractor weight.









roughing out the bearing pockets.


I set the bearings about 5 thou tight on the bar and surface ground the bar to fit. The bar was ground with a paper shim to tilt it So the top of the bar is 3 thou wider than the bottom. This keeps the block seated on the bar all the time. It slides really nicely



I lubed it up to see the "in use" friction



More to come....
 
#25
They are not adjustable. I adjusted the fit by purposely making them too tight then surface grinding the bar till it was a nice fit with no play. I think it will be fine. If not, i can make another, or add cams or something.

I was going to use a linear rail and bearing block, but all the ones i have are matched pairs. Doing it over I might use linear rails and bearing blocks for both upper and lower bars, with a 1/2"x 3" plate sandwiched between, instead of cutting that long dovetail, but what fun would that be?