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Small homemade portable line boring tool

Vince D

Aluminum
Joined
Aug 25, 2007
Location
central wisconsin
Has anyone built or have an idea of how to build a small (3" bore and under) portable line boring tool. I'm rebuilding an old Ford backhoe and the boom pivot pins need work. Someone did a poor repair job and installed overrsize pins with no bushings. This backhoe is for playing around on my land not commercial use, so I wound like to do it has cheaply has possible. I know there are people that do this in my area but they get big bucks to come out and do it. I also have seen Earl Hanson's website, but his info and instructions cost alot. Has anyone ever purchased his books or CDs? Is it worth the money?? I know if I saw one setup and operated I could make my own. Any thoughts...
 
I'd make a couple of match bored plates to tack onto either side, then make a boring bar to fit inside. You'll have to stand them off enough to get the cutter inside there and adjust it. Just a rough idea for you.
 
Thanks for the links to the threads guys, but I had already did a search on this and read those threads. My opinion is they briefly touched on the tooling and setup and mostly told about how it was a tough line of work to be in. Also most of it was larger bore line boring 6" and bigger with 1.5"-2" bars. I'm looking for a smaller scale setup under 3". Any pictures videos and explainations would be great. I kind of understand that basically your just centering a bearing on each end of the bores and running a boring bar through it.
 
I don't have any info as to make your own but if you go to www.youtube.com and search "York 4-14ET line boring Machine" you'll find an actual commercial one in use and the setup used to center the machine. It's not "build your own" of course but it will give a good idea of exactly what it takes. Hope this helps.
 
I can not see a backhoe pivot pins needing precision alignment, if they are anything like my forklift mast pivots. I just machined some new bushes and pins and used a die grinder to clean up the un bushed bores till the over sized pin had good bearing. If the machine is not in commercial service and your pins have a grease nipple which is used to lubricate them regularly then they should give good service.

FWIW I made line boring bar for machining some engine mains but I used a mill to supply the feed and rotation, while the bar ran in bronze bushes.
 
I had similar questions about portable line boring some time back and talked to a guy doing some fab work for our company who had one and told me about the video. I don't have any need for one but would sure like to have one lying around to play with. Glad I could help
 
And when you make the boring bar you don't have to broach square holes for the tool bit. Round holes work OK with square tool bits for occasional use. Don't put the hole through the center of the bar, you want the cutting edge on center.
 
This is the general idea of a line bore. The crank is used to feed. Some kind of motor is required to rotate the spindle. Adjust bore diameter by moving the tool farther from center.

lineborejpg.jpg


Jim
 
hi
look at all portable inline boring bars and you will find all tool holes are on centre line of the bar

True, but I'll bet you'll also find they've got a line of grossly overpriced cutting tools they'll sell you for use with the on-center holes.

If a person is making their own, it makes the most sense to put the hole off center sufficiently to put the cutting edge on center such that standard tooling can be used.
 
boring bar

hello all, we set up to restore the lower pin holes on 520 dresser using 1.5 inch ground+polished line shafting 7 ft $70, 2 flange bearings $ $80 1/2 square broach $135 1.5 hyd rod wiper set in alumn plate spring loaded to lower bearig bracket to keep the chip from interfering w/smooth shaft to bearing fit. we turned top of bar to fit hougan mag drill,gave it a flat, located w/ cones from alunm round heavy tack welds on the bearing brackets and done. drill+broach 1/2 squares as needed. we stick welded worn holes. we did 2 pads 4 inches apart 1.125 thick. we used hss w/no problems, just a little bumpy to start. not enough work on LI to warrant spending on or even renting climax or the equivelant set up. surf
 
True, but I'll bet you'll also find they've got a line of grossly overpriced cutting tools they'll sell you for use with the on-center holes.

If a person is making their own, it makes the most sense to put the hole off center sufficiently to put the cutting edge on center such that standard tooling can be used.


The validity here is with holes on the center. you need to grind away
nearly half the thickness of the tool bit.
Or work above center, but the draw-back there is if you need to cut say
another 3 thou/side out you can't just slide the bit the .003".
The math won't work-out.

Realise too that with bit-holes offset, the set-screws press against
the bottom of the tool-bit, bringing the top level of the bit-nose to shaft-center.
Minimal grinding now does the trick.
M1M
 








 
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