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383 240z
08-09-2011, 02:20 PM
I need to put a boring bar on my lathe, I know that the commonly available QCTP's will do this, (look at my QCTP thread) However why spend the coin if I dont have to as pointed out by a few. I thought about making a block of steel with a 1/2" hole in it. and a couple of set screws to hold the bar, then chuck it in my 4 way, use feeler gauges to set the height and start cutting. Is this the best way? Anybody have a photo of what it is supposed to look like? Any tips for a guy who is not a machinist and is kinda clueless as to what I am doing? Keith

HWooldridge
08-09-2011, 02:29 PM
I did something similar on my first lathe and it worked fine. I put a Jacobs chuck in the main 3-jaw and center drilled the block (previously mounted on the compound) then drilled the finished hole. I figured this was the easiest way to get the center lines to match. I bored a lot of holes with this setup until I was able to buy a QCTP.

wheeltapper
08-09-2011, 02:34 PM
Hi.
something like this perhaps.
http://i293.photobucket.com/albums/mm72/wheeltapper_2008/model%20engineering%20stuff/topslidefreeboringbarholder.jpg

cheers
Roy

dockrat
08-09-2011, 03:47 PM
I originally made this double barreled one for my fourway before I got my quick change. It works in both tool holders.For 1/2 and 3/8 boring bars. ( no I dont use both bars at once!!! LOL :p )

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1066Medium.jpg

I made a couple of singles later on for the QCTP

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1518Medium.jpg

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1544Medium.jpg

383 240z
08-09-2011, 03:50 PM
Thanks for the pics, and the tip about drilling it on center. I think I have some 1.5" x 1.5" stock at the house, if not the local steel supply is flush with the stuff. Thanks guys. Keith

Willy
08-09-2011, 04:00 PM
There is also this option sized to fit your boring bars and 4-way.

http://i76.photobucket.com/albums/j31/250willy/c8e79d95.jpg

383 240z
08-09-2011, 05:01 PM
That is a novel approach, I never thought to drill it on size and make a relief cut and use the set screws to hold it, I was worried about the margins but I'm sure that if I have some 1"x1" CRS I will have enough room for what I have in mind. Also I'm only cutting 6061 when I'm done and I can take all day to make the cut I'm in no rush. Not like I am cutting 304SS with a time clock ticking. Thanks again. Keith

vpt
08-09-2011, 09:19 PM
I drilled out a blank tool holder for the boring bar.

http://img254.imageshack.us/img254/9068/boringbar015.jpg

DATo
08-09-2011, 09:32 PM
Those are some nice looking boring bar holders. My compliments to all.

Joel
08-09-2011, 11:34 PM
http://img.photobucket.com/albums/v186/JoelinTX/BoringBar2.jpg

383 240z
08-13-2011, 07:02 AM
Well I did it I came up with a way to hold the tool bit. More on that in a bit. Anyway here are is a pic of the results. http://i1106.photobucket.com/albums/h377/383240z/counterbore.jpg

Now here is how I did it. Please dont kick me out!
I was planning on taking a 2" long x 2.5" CRS mill it to fit my 4 way, bore it to hold a boring bar and do it that way.

Then the red-neck side of me comes out on the walk to the shop. I did tell you I'm nothing more than an educated hill-billy right? Anyway I start thinking about all the work ahead just to make a tool to make a part, not a cool part just a little adapter, and its the only part keeping my Jeep off the trail. So I start thinking, why cant I just bolt the thing down in the 4 way?? I mean Im just cutting AL and they are shallow cuts. Im at the shop now and I am thinking about this plan.

First problem, height, I drop the round pin in the square hole and I'm low real low. So I put an 1.8" shim under the bar and it brought me REAL close to center. Next problem rigidty, So I chuck up a length on 3" thick wall AL tube, same material as my work piece and same dim. So I put it in the tube, run the cross feed out till I make contact, add a few thou and engage the carraige. IT WORKS!!!!! Next up a deeper cut 0.010", works! 0.020" works!!
No chatter, clean even cut.

Now I know that this was not bright, and could have even been danger inducing. However The lock pins set in front of the centerline of the boreing bar locking it into the four war, and it was a brand new bar so it was very sharp and I was, for the first time, using ALL the safty guards, no cuts were made with the shield up, I never stood infront of the work while it was cutting and I always wear eye protection.

Yep its a dumb way to do it, yet it yielded good result with no drama. Is it the way I'm going to do all my boreing operations? Nope! All it did was allow me to move forward with this project until I can afford a proper tool holder, I have decided that a Phase II QCTP is in my near future, just need to add a few more bucks to the tool fund, as I made a decent withdrawl to cover the last batch of HSS tool bits I ordered from ENCO. Keith

Your Old Dog
08-13-2011, 07:12 AM
I made one like Ernies below only I used aluminum and it works fine. Probably wouldn't hold up for commercial duty but for home use it's fine with a 3/4" bar in it.

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1544Medium.jpg

davidwdyer
08-13-2011, 07:15 AM
If you are saying that you just clamped a boring bar in a 4 way tool post holder with a shim under it, I don't think you are the first "red-neck" to do that.
I bet this forum is full of such.

jugs
08-14-2011, 04:22 PM
I originally made this double barreled one for my fourway before I got my quick change. It works in both tool holders.For 1/2 and 3/8 boring bars. ( no I dont use both bars at once!!! LOL )

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1066Medium.jpg
quote]

I imagine that amount of overhang must be prone to chatter except on very light cuts .



[quote]
If you are saying that you just clamped a boring bar in a 4 way tool post holder with a shim under it, I don't think you are the first "red-neck" to do that.
I bet this forum is full of such.

davidwdyerIf you are saying that you just clamped a boring bar in a 4 way tool post holder with a shim under it, I don't think you are the first "red-neck" to do that.
I bet this forum is full of such.

:eek: Isn't that the correct way then :D

john
:)

loose nut
08-14-2011, 05:41 PM
ever tried to bore two holes, at the same time, on your lathe with that.

Give it a try and get back to us.:D :D :D

PixMan
08-14-2011, 05:53 PM
You'd be surprised at how many times I had to fight setup problems like that on CNC Swiss-style machines with back-work tools. The tool centers are usually no more than a few millimeters more than the diameter of the pick-off collet. That means very little room between the tools and the spindle nose.

I really don't miss the days of setting up those machines all that much. ;)

rohart
08-14-2011, 06:11 PM
Depends now what is meant by a boring bar. I have a couple of boring bars that take inserts. From memory, the diameters of the shanks are 16mm and 12mm - that's 5.8" and 23/64" to the 'new world'.

Mine have significant flats on their sides. I have no hesitation in clamping them in a holder for my QCTP, and barring eye protection I don't hold with much of the extra safety features.

If the OP is clamping a cylindrical boring bar, yes, I would stand well back. But one with flats - no problemo.

So, if the OP's boring bar has no flats, and is not hard, milling flats won't take anything like the time to mill holders, and in my book that would be a permanent fix. Grinding flats on hard, well, that would be a more extended project. Might need a fixture for that. Lets see...

383 240z
08-15-2011, 08:08 AM
yep it's a round cutter, ie: no flats. The thought had crossed my mind to cut flats on the BB to be a bit more safe, and make the tool cut better. However the thought of making the cut just a bit off and having the bar be usless for this job. Keith

Mcgyver
08-16-2011, 06:58 PM
this is potentially a great thread, suffering from an bad handle...not knowing or carry much about round or square pegs i ignored it for most of its existence...it would be preferred at least by me to use a more meaningful title in the future (thanks). having stumbled across it, I thought I'd share a few pics on boring bar holders

The baseline is holding the BB right in the QCTP cartridge. Either in a round split sleeve as shown, or without - they often have flats on the top and bottom

http://i20.photobucket.com/albums/b201/michael0100/DSC_9457mod-large.jpg

I made a pile of Dickson holds recently and made two a little over sized and filled them with holes. Between the two they'll 6 difference sizes.

http://i20.photobucket.com/albums/b201/michael0100/DSC_9451mod-large.jpg

The ultimate is this copy of the Williams style. Its the most solid way to hold even the largest of boring bars. It gets mounted right in the T slot. Finished one is for the small lathe, Unfinished is for the DSG...it'll get done next time i screw up the courage to lift the indexing head onto the mill

http://i20.photobucket.com/albums/b201/michael0100/DSC_9453mods-large.jpg

Mcgyver
08-16-2011, 06:58 PM
http://i20.photobucket.com/albums/b201/michael0100/DSC_9454mod-large.jpg



http://i20.photobucket.com/albums/b201/michael0100/DSC_9452-large.jpg

383 240z
08-17-2011, 12:44 AM
Mcgyver, those are some pretty bad ass holders!! I however an interested in those square BB's I've just about saved up the folding money I need to purchase the Phase II QCTP and holders I have sold myself on. Here is a link to the link of the finished part with photos. http://bbs.homeshopmachinist.net/showthread.php?t=49332 Thanks again Keith

jack3140
09-29-2011, 09:04 PM
http://i20.photobucket.com/albums/b201/michael0100/DSC_9454mod-large.jpg



http://i20.photobucket.com/albums/b201/michael0100/DSC_9452-large.jpg
many thanks for the pics i will now make one for myself could,nt be clearer jack

Don Young
09-30-2011, 12:10 AM
If you are saying that you just clamped a boring bar in a 4 way tool post holder with a shim under it, I don't think you are the first "red-neck" to do that.
I bet this forum is full of such.

My first lathe job was boring an aluminum block cast with a pattern made from a piece of 4X4" wood. I didn't do the casting. I cut a 3/4" hole thru it using a hole saw from both sides and bolted it to the faceplate of my AA Products lathe with some washers behind for clearance. I clamped a 3/8" drill bit in the lantern tool post, rotated and angled it so one lip had some sort of clearance and a some sort of rake. I then bored the hole out to match some bent fork tubes and split the block apart with a hacksaw. It worked!

boslab
09-30-2011, 07:38 AM
all you guys, nice work, i like the double barrel purdy 12 guage/410 combo!
regards
mark