2020 POTD Thread Archive

Also, I ran some beads with my new Everlast 210 EXT at 160 amps and it does a fine job. Also, I am wondering if anyone
knows if one could TIG weld in the imperfections caused by the stick welding. There is slag in those black areas so
hoping to clean up my welds.


Grind it out a little and fill it back in..... Clean it with solvents before welding.....
 
I finally finished the chuck adapter for the dividing head. All I needed to do was part it off so it wasn't so long, then face it and clearance the thread. Yes, I chucked up a rod in the lathe chuck, then bore down on that rod with this dividing head chuck like the noogies we all endured in high school :

20200212_200047.jpg


20200212_201003.jpg


Then I could install it :

20200212_201630.jpg


I'm excited! If my table is big enough and I can drop the tailstock, dividing head, and the gear blank, I'm ready to start cutting gears!
 
POTD was making a couple of bushings for the suspension of a buddy's snowmobile. The suspension looks from a photo to be a large swing arm with a pair of torsion springs reacting between the frame and arm. My buddy enjoys his Old Milwaukee and Twinkies and needed to beef up the springs which have a much larger ID/OD. There are isolating bushings between the pivoting axle and the ID of the springs so there’s no metal to metal contact; new springs take larger bushings. He bought a couple of 3-D printed isolators that ran about $100 for the pair. That cut substantially into his Old Milwaukee and Twinkie budget, so asked if I could make something similar.


Buddy's snowmobile's suspension uses a couple of bushings to isolate the torsion springs from an axle.
1rearcomponents.jpg
s-l225.jpg


Pretty simple lathe job though I used different methods for each bushing. Kind of chicken and the egg thing; bore out the center then work the OD, or work the OD then bore out the center. Did the first one using the former method.

Faced, center drilled and drilled a 1” starter hole. The ID was something like 1.389” off the 3-D printed part, but he wanted a little extra clearance so bored to 1.400”. I’d typically stick as much material as possible into the chuck jaws but purposely left a gap for easier removal of swarf. The boring bar pushes everything towards the chuck so I left some room to pull the chips instead of using a ram rod to push them through the spindle or a hook to pull them from the opposite side. I was using Delrin which is really easy turning so wasn’t too worried about knocking the work out of the chuck. If it was steel or aluminum, I’d have pushed the work all the way into the chuck.


Faced and center drilled
20200208_123859.jpg

Drilled a clearance hole for boring
20200208_124829.jpg

Set the boring bar to make it through the stock ahead of time
20200208_125352.jpg

Boring the center hole to size
20200208_130648.jpg

20200208_132345.jpg



After boring to size, slid the work out of the chuck and supported the end with a bull-nose center. From there it was just turn to diameter.


Turing the OD while supporting the tail stock end with a bull-nose center
20200208_134755.jpg


There’s a taper on either end of the 3-D part. Chucked up the 3-D part and matched the face of the taper with a tool bit and made the cut on the new part. Then bored the countersunk the hole in the end.


Chucked up the 3-D printed part and rotated a tool bit to match the taper.
20200208_135012.jpg

Cutting the tapered end on the new part
20200208_135327.jpg

Parting off
20200208_135515.jpg

Boring the countersunk hole
20200208_140428.jpg


Pulled the work and faced the opposite end so each end was smooth. I didn’t show it but measured the overall length of the 3-D printed part with a height gauge on my surface plate. Pulled the faced part from the chuck and repeated the height check to get its overall length. No calculator needed to know how much to knock off the end when you have a DRO. Chucked up the work, touched the tool to the face and punched in the measured length. Then faced to the target number to match the length of the 3-D part.


Facing to overall length. Measured the new part length on a surface plate and dialed that length into the DRO. Then simply face to the target number.
20200208_141106.jpg



The opposite end has a longer taper, so matched that by sweeping along the part while adjusting the compound rest to set the angle.


Chucked up the 3-D printed part and moved the compound to match the taper.
20200208_141406.jpg

Cutting the taper on the new bushing
20200208_141845.jpg


I made the second one by first turning the OD’s, then bored the center hole. In retrospect, this was the better method as I could see a bit of run-out on the first part with the bull-nose center.



Finished bushing and one of the two $100 pair headed back to the seller. . .
20200209_194612.jpg


Thanks for looking,

Bruce
 
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Very nice Bruce! May I ask exactly what the material is? I am planning a similar job on my 1978 Corvette. I'm thinking of using Delrin. Is that a suitable material to use for bushings?
 
POTD was making a couple of bushings for the suspension of a buddy's snowmobile. The suspension looks from a photo to be a large swing arm with a pair of torsion springs reacting between the frame and arm. My buddy enjoys his Old Milwaukee and Twinkies and needed to beef up the springs which have a much larger ID/OD. There’s are isolating bushings between the pivoting axle and the ID of the springs so there’s no metal to metal contact; new springs take larger bushings. He bought a couple of 3-D printed isolators that ran about $100 for the pair. That cut substantially into his Old Milwaukee and Twinkie budget, so asked if I could make something similar.


Buddy's snowmobile's suspension uses a couple of bushing to isolate torsion springs from an axle.
View attachment 313501
View attachment 313502


Pretty simple lathe job though I used different methods for each bushing. Kind of chicken and the egg thing; bore out the center then work the OD, or work the OD then bore out the center. Did the first one using the former method.

Faced, center drilled and drilled a 1” starter hole. The ID was something like 1.389” off the 3-D printed part, but he wanted a little extra clearance so bored to 1.400”. I’d typically stick as much material as possible into the chuck jaws but purposely left a gap for easier removal of swarf. The boring bar pushes everything towards the chuck so I left some room to pull the chips instead of using a ram rod to push them through the spindle or a hook to pull them from the opposite side. I was using Delrin which is really easy turning so wasn’t too worried about knocking the work out of the chuck. If it was steel or aluminum, I’d have pushed the work all the way into the chuck.


Faced and center drilled
View attachment 313503

Drilled a clearance hole for boring
View attachment 313504

Set the boring bar to make it through the stock ahead of time
View attachment 313505

Boring the center hole to size
View attachment 313506

View attachment 313507



After boring to size, slide the work out of the chuck and supported the end with a bull-nose center. From there it was just turn to diameter.


Turing the OD while supporting the tail stock end with a bull-nose center
View attachment 313508


There’s a taper on either end of the 3-D part. Chucked up the 3-D part and matched the face of the taper with a tool bit and made the cut on the new part. Then bored the countersunk hole in the end.


Chucked up the 3-D printed part and rotated a tool bit to match the taper.
View attachment 313509

Cutting the tapered end on the new part
View attachment 313510

Parting off
View attachment 313511

Boring the countersunk hole
View attachment 313512


Pulled the work and faced the opposite end so each end was smooth. I didn’t show it but measured the overall length of the 3-D printed part with a height gauge on my surface plate. Pulled the faced part from the chuck and repeated the height check to get its overall length. No calculator needed to know how much to knock off the end when you have a DRO. Chucked up the work, touched the tool to the face and punched in the measured length. Then faced to the target number to match the length of the 3-D part.


Facing to overall length. Measured the new part length on a surface plate and dialed that length into the DRO. Then simply face to the target number.
View attachment 313513



The opposite end has a longer taper, so matched that by sweeping along the part while adjusting the compound rest to set the angle.


Chucked up the 3-D printed part and moved the compound to match the taper.
View attachment 313514

Cutting the taper on the new bushing
View attachment 313515


I made the second one by first turning the OD’s, then bored the center hole. In retrospect, this was the better method as I could see a bit of run-out on the first part with the bull-nose center.



Finished bushing and one of the two $100 pair headed back to the seller. . .
View attachment 313516


Thanks for looking,

Bruce
Typically nice work, Bruce. But of equal value is your informative and logical description of how you approached the project. I think I'm remembering correctly from one of your prior posts that your Dad was a shop teacher? I'm sure he's very proud.

Regards,
Terry
 
Very nice Bruce! May I ask exactly what the material is? I am planning a similar job on my 1978 Corvette. I'm thinking of using Delrin. Is that a suitable material to use for bushings?
These are Delrin and might work on your Vette. On the snowmobile suspension, the springs are torsional so they tighten up or open up the coil when jouncing (winding tighter or looser). The wear/contact will be a squeezing action more than dragging across the surface if they were isolating compression springs. They are under-sized to the fully jounced spring ID. Of course, that's a static look at the use. You'd have to think running down a trail at 70 mph over bumps would move things a little differently than my buddy jumping up/down at a stop. The 3-D printed ones were polyethylene which is more flexible than Delrin, but not nearly as tough. I'm hoping for my buddy's sake that whoever engineered the 3-D printed ones did some actual testing on sleds to confirm PE works!

Bruce
 
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Typically nice work, Bruce. But of equal value is your informative and logical description of how you approached the project. I think I'm remembering correctly from one of your prior posts that your Dad was a shop teacher? I'm sure he's very proud.

Regards,
Terry
Thanks Terry. I can tend to get a little wordy, maybe watched too many Mr. Pete videos and caught something. . . This forum has all levels of experience on it, so might give a tip or technique to someone with less experience or get a better idea from someone with more.

Bruce
 
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