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- Jan 11, 2013
- Messages
- 1,834
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2017 POTD Thread Archive
- Thread starter jpfabricator
- Start date
Made a funny-car style header pipe for my large lawnmower, because, well, who doesn't want a funny-car style header on their lawnmower?
Actually, I made it because the original exhaust pipe was just the short 90 degree angle rusty part that you see, which was pointed forward, but because of the bagger mount, I turned it around. However, this caused the exhaust to heat up the tire, which then appears to cause brown spots in lawns, particularly where the mower sits (say, when I empty the bags). This should solve that problem. Hopefully.
Actually, I made it because the original exhaust pipe was just the short 90 degree angle rusty part that you see, which was pointed forward, but because of the bagger mount, I turned it around. However, this caused the exhaust to heat up the tire, which then appears to cause brown spots in lawns, particularly where the mower sits (say, when I empty the bags). This should solve that problem. Hopefully.
- Joined
- Oct 20, 2014
- Messages
- 133
- Joined
- Oct 20, 2014
- Messages
- 133
A friend had fitted some wheels from a different model to his motorcycle. The width of the hub was 5mm less so he needed 2.5mm thick spacers made up to go between the hub and the brake disc carriers on either side.
There were two of these spacers from his original wheel that he gave me to reduce the thickness from ~7.6mm to 2.5mm and open up the internal diameter from ~73mm to 80mm, removing the boss.
I skimmed the plain face.
flipped it around and secured it with some some copper shims on the inside bore.
reduced the thickness to 2.5mm and carefully started removing the centre boss.
and did the same to the other item.
Then I had to work out how to hold the pieces to bore the internal diameter out to 80mm.
The first cunning plan didn't work, with the piece ending up on the other side of the shop.
This was Plan B. I clamped both pieces onto a brake disc carrier.
and then mounted the brake disc carrier onto the chuck.
and bored the internal diameter.
some deburring and tidy up and the job was done.
pete
There were two of these spacers from his original wheel that he gave me to reduce the thickness from ~7.6mm to 2.5mm and open up the internal diameter from ~73mm to 80mm, removing the boss.
I skimmed the plain face.
flipped it around and secured it with some some copper shims on the inside bore.
reduced the thickness to 2.5mm and carefully started removing the centre boss.
and did the same to the other item.
Then I had to work out how to hold the pieces to bore the internal diameter out to 80mm.
The first cunning plan didn't work, with the piece ending up on the other side of the shop.
This was Plan B. I clamped both pieces onto a brake disc carrier.
and then mounted the brake disc carrier onto the chuck.
and bored the internal diameter.
some deburring and tidy up and the job was done.
pete
- Joined
- Nov 23, 2014
- Messages
- 2,632
POTD was helping out a buddy at work with a broken hay rake. Don’t know where the part works on the machine, but a threaded tube and a threaded crank are run together. There’s a clevis at the end of the tube, so must be some sort of height adjustment on the rake. Regardless, the tube was stripped.
Measured the thread at a 7/8” x 6 tpi Acme thread. This is the first time I can recall turning an Acme thread, so no “cheating” by using 60 deg. carbide inserts. I bought an Acme thread gauge from Enco over 30 years ago that got to see its first use. Ground a HSS bit to 29 deg. and dusted the tip until it fit into the gauge’s “6” groove.
I bored out a piece of CRS to Machinery Handbooks ID for 7/8” x 6 Acme, but went a little deeper because the hay rake shaft was bent. I straightened it out the best I could with a 12-ton press, but could see some pretty rough threads.
After that, mounted a boring bar with the bit on center and adjusted the angle using the Acme gauge held on the side of the bushing to set the tool bit at the proper angle. Got to do this twice as someone forgot to set the compound rest angle first . . . I went with 14 deg. to cut mainly on the lead side and scrape on the trailing side of the tool bit.
Verified the thread when I was getting close with the hay rake threaded rod. Went another 0.015” deep because of the damage to the rod. Didn’t show the operation, but milled a couple of flats on the bushing to get a wrench on it. Frankly, got tired of trying to clean up the damaged threads with a file and went the brute force method.
Bushing was welded onto the end of the (formerly) threaded tube. I’ll let my buddy do the painting. Looks like donuts at work!
Bruce
Measured the thread at a 7/8” x 6 tpi Acme thread. This is the first time I can recall turning an Acme thread, so no “cheating” by using 60 deg. carbide inserts. I bought an Acme thread gauge from Enco over 30 years ago that got to see its first use. Ground a HSS bit to 29 deg. and dusted the tip until it fit into the gauge’s “6” groove.
I bored out a piece of CRS to Machinery Handbooks ID for 7/8” x 6 Acme, but went a little deeper because the hay rake shaft was bent. I straightened it out the best I could with a 12-ton press, but could see some pretty rough threads.
After that, mounted a boring bar with the bit on center and adjusted the angle using the Acme gauge held on the side of the bushing to set the tool bit at the proper angle. Got to do this twice as someone forgot to set the compound rest angle first . . . I went with 14 deg. to cut mainly on the lead side and scrape on the trailing side of the tool bit.
Verified the thread when I was getting close with the hay rake threaded rod. Went another 0.015” deep because of the damage to the rod. Didn’t show the operation, but milled a couple of flats on the bushing to get a wrench on it. Frankly, got tired of trying to clean up the damaged threads with a file and went the brute force method.
Bushing was welded onto the end of the (formerly) threaded tube. I’ll let my buddy do the painting. Looks like donuts at work!
Bruce
- Joined
- Nov 23, 2014
- Messages
- 2,632
Hi John,
Good thought, I have a set of 60 deg. files and they work pretty well. I did some Google searching and didn't find anything at MSC, Grainger or Nicholson, but could be my search text is off. It got to the point where I was thinking of making something to clamp the file at the correct angle. Was contemplating a flat plate with a 14 1/2 deg. bevel cut on the end, clamp the file to that with the file extended just below the bottom side of the plate. Then run the file back/forth on the thread with the plate up hard on the rod. Also thought about having my buddy buy a 7/8" x 6 nut and rod. Found a 3' length of rod for $19, nut for $4.25.
Best regards, Bruce
- Joined
- Apr 1, 2013
- Messages
- 1,142
Nice job ! just wonder why you could not chuck them up from the out side to bore. Was it lack of reversible jaws?A friend had fitted some wheels from a different model to his motorcycle. The width of the hub was 5mm less so he needed 2.5mm thick spacers made up to go between the hub and the brake disc carriers on either side.
There were two of these spacers from his original wheel that he gave me to reduce the thickness from ~7.6mm to 2.5mm and open up the internal diameter from ~73mm to 80mm, removing the boss.
I skimmed the plain face.
flipped it around and secured it with some some copper shims on the inside bore.
reduced the thickness to 2.5mm and carefully started removing the centre boss.
and did the same to the other item.
Then I had to work out how to hold the pieces to bore the internal diameter out to 80mm.
The first cunning plan didn't work, with the piece ending up on the other side of the shop.
This was Plan B. I clamped both pieces onto a brake disc carrier.
and then mounted the brake disc carrier onto the chuck.
and bored the internal diameter.
some deburring and tidy up and the job was done.
pete
- Joined
- Feb 2, 2014
- Messages
- 1,212
I saw this idea on the forum a while back but can't find it now. They gave some good reasons why this configuration would help with your cut-off issues.
I started with a used piece of steel that already had a hole drilled in it so just disregard the hole.
An upside down parting tool holder. The lathe is run in reverse so not a great idea if you have a screw on chuck.
This should help to eliminate the tool digging into the work and jamming up.
Also the swarf falls off instead of piling up on the blade.
I would like to reread that original post if anyone knows I can find it.
Ray
I started with a used piece of steel that already had a hole drilled in it so just disregard the hole.
An upside down parting tool holder. The lathe is run in reverse so not a great idea if you have a screw on chuck.
This should help to eliminate the tool digging into the work and jamming up.
Also the swarf falls off instead of piling up on the blade.
I would like to reread that original post if anyone knows I can find it.
Ray
