Author Topic: Just Some Boring Work  (Read 869 times)

Offline gtermini

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Just Some Boring Work
« on: December 16, 2022, 12:04:42 AM »
Been helping a local one-man repair/job machine shop out. He has a 4"/100mm boring mill and got put on it for a few jobs.

Re-bored a 3-1/2 bore hyd cyl out of a log grapple to 4" because the mfg updated the design and the owner only wants to stock 4" packing kits, as he trashes these on a regular basis. Used a Devlieg micro-set intergrated shank tool and had to stick the spindle out a bit to get 19" to the bottom. There's supposed to be like 4 more of these to do soemtime. Takes about 4 hrs to setup and bore.



This is the link the goes between the stick and a processor head on a log shovel. About 6" sq section solid. End bore was trashed. Bushings had turned to gravel and gotten beaten in the bore. Supposed to be 3". Had to overbore to about 3-5/8 to clean it all up before welding up to about 2.5, then bored back to 3.000 for a 3 thou press on new cat hard bushings. Cat bushings are nice because they cut them to press fit size for an on-nominal bore, so you don't have to figure fit out. These measured 3.0025 out of the box.







Here's the swing tower off a cat 305cr mini excavator. Bored the un-bushed pivot holes from a ovaled out 90mm to 3.625 to clean them up. A new, larger pin was made up.



Offline goodfellow

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Re: Just Some Boring Work
« Reply #1 on: December 16, 2022, 07:31:29 AM »
Pretty nice setup work. The time it takes to do it right the first time is worth it.


Offline jabberwoki

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Re: Just Some Boring Work
« Reply #2 on: December 16, 2022, 10:59:23 AM »
I like that little welding jig on the table.
Is the need enough? Or does the want suffice?

Offline Uncle Buck

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Re: Just Some Boring Work
« Reply #3 on: December 18, 2022, 06:03:51 PM »
Shop made answer to a tail stock, very cool. When I worked at Wenger they were turning on shafts 10' or more between the chuck and the tailstock. Given the length of the work the pressure against the shaft at the cutter was actually great enough to cause material as large as 3-5" in diameter to flex and bend  during machining. One of their bright engineers designed what he called a floating chuck. The setup looked like a steady rest, but employed the use of a standard lathe chuck that while secured to the material being machined also spun freely with the material that was chucked into it. I recall asking why this was needed instead of simply using the steady rest. The reply was the steady rest left evidence of its use while the floating chuck did not. It was a very cool device and though I have probably been through several hundred machine shops in my career I have never seen another device like it.
You boys better hold on cause I'm gonna have to stand on it!

Offline gtermini

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Re: Just Some Boring Work
« Reply #4 on: December 18, 2022, 06:37:17 PM »
Long shafts start doing weird things in the lathe and that sounds like a great solution to the problem. Just the thermal expansion on a 10 ft shaft can make it bow like a banana  between centers.

There's a tailstock and a couple larger boring bars (3" and 5") but I didn't want to wrestle the 10 ft bars for that little job. It was nice having enough table travel to be able to move to clear the bar for measurement.