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9 x 20 half nut problem
- Thread starter savarin
- Start date
- Joined
- Aug 22, 2012
- Messages
- 4,292
Started milling the waste material with an end mill but it was very rough finish.
So I ground a broken tap to a small raked flat tip cutter and used a small boring bar to remove the rest.
Now its being filed down for the final fit.
Meanwhile -
can anyone see a reason as to why I cannot cut a channel or drill a hole for the extended cross slide lead screw at the end of the cross slide so the nut can travel a bit further?
Would a channel weaken the saddle too much?
As its in bits to do all this plus replacing the headstock bearings I thought why not go here as well.
If I was designing this I would have placed a roller bearing there for the end of the lead screw but thats probably a bit of overkill.
So I ground a broken tap to a small raked flat tip cutter and used a small boring bar to remove the rest.
Now its being filed down for the final fit.
Meanwhile -
can anyone see a reason as to why I cannot cut a channel or drill a hole for the extended cross slide lead screw at the end of the cross slide so the nut can travel a bit further?
Would a channel weaken the saddle too much?
As its in bits to do all this plus replacing the headstock bearings I thought why not go here as well.
If I was designing this I would have placed a roller bearing there for the end of the lead screw but thats probably a bit of overkill.
- Joined
- Aug 22, 2012
- Messages
- 4,292
I decided I needed a key for the handle so thought a woodruff type would be the easiest to make.
I ground a thin cutter and fixed it into a boring bar.
The bar was held in the chuck and the shaft I wanted to keyway cut was held in a wedge type QCTP holder.
I set the height so the cutter was centered on the shaft and just kissing it.
Locked the saddle and cross slide.
Then the cringe bit.
Gently loosened the holder and adjusted its height so the cutter started cutting, gently tightened the holder which had the propensity to raise the shaft parallel again and cut a little more. Repeat untill the slot is deep enough.
Not a brilliant photo but hopefully you can get the drift.
I ground a thin cutter and fixed it into a boring bar.
The bar was held in the chuck and the shaft I wanted to keyway cut was held in a wedge type QCTP holder.
I set the height so the cutter was centered on the shaft and just kissing it.
Locked the saddle and cross slide.
Then the cringe bit.
Gently loosened the holder and adjusted its height so the cutter started cutting, gently tightened the holder which had the propensity to raise the shaft parallel again and cut a little more. Repeat untill the slot is deep enough.
Not a brilliant photo but hopefully you can get the drift.
- Joined
- May 16, 2016
- Messages
- 1,704
G'day Charles, I'm still constantly amazed at the new ways you can create to do the impossible with next to nothing. Your continued use of excessive overhang to get good results is mind boggling as always.
Carry on you've got me beat. I look forward to the day when I'm next in Qld, and I can see some of your toys.
Carry on you've got me beat. I look forward to the day when I'm next in Qld, and I can see some of your toys.
- Joined
- Aug 22, 2012
- Messages
- 4,292
as you can see there is a brass shim under the holding screws.
The test bar didnt use the shim and a too heavy a cut actually spit the shaft out of the holder making a neat row of divots along its length.
The cutter touched, gripped and levered the shaft out one rotation at a time.
All good fun.
The test bar didnt use the shim and a too heavy a cut actually spit the shaft out of the holder making a neat row of divots along its length.
The cutter touched, gripped and levered the shaft out one rotation at a time.
All good fun.
- Joined
- Nov 29, 2017
- Messages
- 556
"The test bar didnt use the shim and a too heavy a cut actually spit the shaft out of the holder making a neat row of divots along its length.
The cutter touched, gripped and levered the shaft out one rotation at a time."
Saw this happen in the shop where I worked. Operator was cutting key seats in a 2 7/16ths x 12' shaft. Machine was a Summit universal mill with a 10 x 54 table set up in horizontal arrangement. Hold down clamping was inadequate and pulled the shaft into the cutter. Amazingly the cutter didn't break. Pulled the entire length of shaft past the cutter. It did trash the cutter mandrel.
The cutter touched, gripped and levered the shaft out one rotation at a time."
Saw this happen in the shop where I worked. Operator was cutting key seats in a 2 7/16ths x 12' shaft. Machine was a Summit universal mill with a 10 x 54 table set up in horizontal arrangement. Hold down clamping was inadequate and pulled the shaft into the cutter. Amazingly the cutter didn't break. Pulled the entire length of shaft past the cutter. It did trash the cutter mandrel.
- Joined
- Aug 22, 2012
- Messages
- 4,292
Cut the keyway in the handle by grinding a carbide (horrible) small boring tool thinner and used the saddle handle to gently cut away the slot.
I used the same process of lowering the tool holder after every pass.
To stop the chuck rotating I locked it with my indexing system.
I have got to get my act together and clean, polish and blue all my made tools in a forlorn attempt at beating the humidity rust bug.
I used the same process of lowering the tool holder after every pass.
To stop the chuck rotating I locked it with my indexing system.
I have got to get my act together and clean, polish and blue all my made tools in a forlorn attempt at beating the humidity rust bug.
Here in Louisiana, humidity is a given. Yet with a gas fueled water heater for the house actually located in the garage where I do my machining, no worries of rust at all. I also periodically spray WD on bare surfaces & run a small electric heater while working. Your project is looking good!
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