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- Nov 23, 2017
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Grind it out a little and fill it back in..... Clean it with solvents before welding.....
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2020 POTD Thread Archive
- Thread starter eugene13
- Start date
Grind it out a little and fill it back in..... Clean it with solvents before welding.....
- Joined
- Mar 26, 2018
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- 8,664
They are great for marking your stock on the lathe!
- Joined
- Mar 17, 2018
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- 1,400
The bottom die of my press brake, ready for welding.
- Joined
- Dec 6, 2015
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- 829
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 :
Then I could install it :
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!
Then I could install it :
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!
- Joined
- Nov 23, 2014
- Messages
- 2,634
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.
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
Drilled a clearance hole for boring
Set the boring bar to make it through the stock ahead of time
Boring the center hole to size
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
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.
Cutting the tapered end on the new part
Parting off
Boring the countersunk hole
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.
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.
Cutting the taper on the new bushing
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. . .
Thanks for looking,
Bruce
Buddy's snowmobile's suspension uses a couple of bushings to isolate the torsion springs from an axle.
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
Drilled a clearance hole for boring
Set the boring bar to make it through the stock ahead of time
Boring the center hole to size
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
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.
Cutting the tapered end on the new part
Parting off
Boring the countersunk hole
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.
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.
Cutting the taper on the new bushing
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. . .
Thanks for looking,
Bruce
Last edited:
- Joined
- Mar 17, 2018
- Messages
- 1,400
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?
- Joined
- May 3, 2017
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- 2,026
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
- Joined
- Nov 23, 2014
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- 2,634
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
Last edited:
- Joined
- Nov 23, 2014
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