Line boring machine

[motorworks]

A few weeks back John posted a drawing of a self-feeding boring bar.
I built one using the bases of his idea.
I Used 1" AL flat bar for the frame (left over from a job) AL bar for the "red" adapter and 6203-3/4" 2RS bearings.
3/4" cf bar for the stands offs and boring bar.
Most of the pin holes I do are of the 25 to 35mm range.
The boring bar is threaded and keyed.One of the large (40t) sprockets has a key slot and the other is tapped for 3/4-16 thread.
As it turn out it was not that heavy.

Pic 1 shows machine layed out. Note there are no cross holes for the tool bits yet in the 3/4"
boring bar as I am waiting for the first forklift job later this week.I will mark and put them in place then.

http://img.photobucket.com/albums/v22/motorworks/Picture061.jpg

Here is the 1/2'' drill mounted the main body.I have an anti-rotate bar to save me wrists!

http://img.photobucket.com/albums/v22/motorworks/Picture062.jpg

The RED piece bolts to the main frame and then to the steel sacrificial plate(not shown) that is welded to the frame.The tapered cones are used to line up the bar.
The 2 bolt 3/4" flange block bearing goes on the opposite of the drive end.
I am using a #40 chain drive with a 3:1 ratio so with the drill running at 550 the bar turns at 184 RPM.
The difference sprocket is 12/13 and using a 3/4-16 thread I am getting a 0.004"/rev feed
I will post pics and or a video of it working if I get time.
I also plan on putting a limit switch on it so that it will shut off
at a set point.
One other small change will be one of the smaller sprockets will have
the key removed and be held to the shaft via a quick release pin to speed set up.

http://img.photobucket.com/albums/v22/motorworks/Picture067.jpg

eddie

[John Stevenson]

But does it work when you press go ?

.

[motorworks]

"But does it work when you press go ?"

Yes, and it is just like an old girlfriend I had,
sometimes it starts without me... :)

[trap]

If I understand this correctly for every turn of the boring bar it will feed in .0625. You will be cutting threads the same as what's on the boring bar.
Hopefully I am thing wrong.

trap

[motorcyclemac]

[QUOTE=

Yes, and it is just like an old girlfriend I had,
sometimes it starts without me... :)[/QUOTE]

Sounds wonderful.... Do you happen to still have her number?

Cheers
Mac.

[John Stevenson]

If I understand this correctly for every turn of the boring bar it will feed in .0625. You will be cutting threads the same as what's on the boring bar.
Hopefully I am thing wrong.

trap

Yup, you are not taking the 12/36 x 13/36 differential gear into account.

.

[motorworks]

trap
No
The bar will advance 0.0048" per revolution

12/13 x .0625= 0.0577"
1/16= 0.0625"
Because of the differerential you get 0.0625-0.0577=0.0048

[motorworks]

"Sounds wonderful.... Do you happen to still have her number?"

I was no fool.... I married her,..... but then she stopped :)

[John Stevenson]

Tell me about it.

Life sucks.

the job sucks.

The wife doesn't...............................

.

[wierdscience]

Nice setup Eddie,what size bores do you expect it can handle?

[motorworks]

"wierdscience
Nice setup Eddie,what size bores do you expect it can handle? "

Thanks!!

I will use it mostly for king pins on forklifts.
They are usually 25- 35mm pin holes "egged shaped out" .
I pretty sure I can fit a larger bar if needed via a screw on coupling.

[motorworks]

"The wife doesn't..............................."
John
Heard today that the Government is working on a Vaccination to cure
this. Right after they fix this H1N1 :D

[doctor demo]

Eddie, that is a nice compact set up! How big of a tool bit do You think You are going to use? Instead of a hole through the bar for the bit , could a shaft collar be used so as not to weaken the bar, and make tool location more adjustable ?


Steve

[motorworks]

Thanks Doc
I have used a 3/4" bar in the past on forklifts king pin bushing holes.
The hole are usually 25-35 mm in diameter, the reason for the smaller bar.
I use 1/4" carbide tools and sometimes 5/16"
I usually round the corners so they fit in a round hole.
Never broke one yet, "knock on wood".

"Instead of a hole through the bar for the bit , could a shaft collar.."

Nice idea Doc ;)

[boslab]

i must say it is simple, robust and well made. in simple engineering terms the word 'elegant' springs to mind, i'm inspired to copy what i see and thats rare, well done
mark

[John Stevenson]

i must say it is simple, robust and well made. in simple engineering terms the word 'elegant' springs to mind, i'm inspired to copy what i see and thats rare, well done
mark

You can't, it's still under John Wilkinsons patent of 1775

http://www.makingthemodernworld.org.uk/stories/manufacture_by_machine/03.ST.01/img/IM.0429_zl.jpg

:rolleyes:

.

[boslab]

You can't, it's still under John Wilkinsons patent of 1775

http://www.makingthemodernworld.org.uk/stories/manufacture_by_machine/03.ST.01/img/IM.0429_zl.jpg

:rolleyes:

.
i'm sure he wont mind, theres more to learn in this world than theres time to do it crosses my mind.
still i liked the chaindrive it looked so buisnesslike, not a bloody stepper in sight
regards
mark

[luthor]

Very nice work Eddie, I have often thought of building something like this for repairs to my Bobcat. I am having trouble understanding the actual drive mechanism, any chance you could post pictures of the actual components and a short explanation of how the differential drive actually works.

[motorworks]

luthor:
Below is the OEM drawing from Super John of the UK.
I will use it to try and explain how the differential drive works.
The boring is threaded and keyed. In my case I used 3/4-16 threads.
Gear A is keyed with a slide fit to the boring and Gear D is threaded to fit the boring:3/4-16. Gears B and C are what mades the differenital.They are keyed together on the shaft.
As the boring bar turns, A drives B which in turn drive C that drives D
If B and C had the same number of teeth then the bar would rotate but not
move a head. If the gear C was no longer keyed to the shaft then the feed would be equal to the pitch of the thread. In this case 1/16''/rev or 0.0625''/rev. A much to high a feed for a boring bar of this type.
Through the differenital gears (B and C) the feed becomes less/rev.
As the bars turns ahead so does the tapped gear.Just picture a rod screwing into a nut and the nut turning at almost the same rate and direction as the bar.The bar will move a head but not as far.
In the drawing we got from John the Differenital thread movement is as follows:
Since both drive gears A and D are the same size they cancel each other out.
Assume a 3/4-16 threaded bar;

1/16= 0.0625'' without the differenital the feed would be 0.0625"/revolution

Factor in the differenital;
19/20 x 1/16= 0.0594''
Because both nut and bar are turning in the same direction BUT at a different
rate we get a finer feed
The new feed will be 0.0625"/rev - 0.0594"/rev = 0.003"/rev

clear as mud ;)
eddie


http://img.photobucket.com/albums/v22/motorworks/Boring20bar.png

[Rich Carlstedt]

When we line-bored the journals on our punch presses ( 6" to 8 " bearings),
The boring bar 3-4" diameter was turned on a lathe with a fine feed using a "V" tool bit. The bar was quite long to span both journals and then some.
A pulley was placed on one end to drive, and then two hardwood blocks were clamped on the shaft and locked to the frame.
The result was the shaft feeding at about .003" per turn , using the wood blocks as nuts and the surface of the bar became a thread.
Worked great and is very simple to duplicate.
not my idea..
Rich

[luthor]

Thanks for the explanation Eddie.

[luthor]

1. Have you tried it out yet?

2. What type of bearing arrangement do you have for the sprocket drive?

[motorworks]

"Have you tried it out yet?"

No not yet. Two rear ends in this week but no king pin work

" What type of bearing arrangement do you have for the sprocket drive?"

I am using two 6203-3/4" 2RS bearings mounted in each AL plate end

e2die

[lazlo]

Great work Eddie -- very impressive!

We all want to see it bore! :)