Using the lathe and a 4j chuck as a boring head?
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  1. #1
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    Default Using the lathe and a 4j chuck as a boring head?

    I have a part I need to bore a very accurate hole in. I can't mount it in a 4j, and I dont have a mill. I can, however, get it mounted to the cross slide. The easiest solution would obviously be to mount a boring head in the headstock and do it that way, but I don't have one. I do have boring bars and a 4 jaw, so i'm thinking I can use that to dial in an offset. Does anyone have any experience with this, or any suggestions for me? Hole is about 1.375" for reference.

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    Quote Originally Posted by Domodude17 View Post
    I have a part I need to bore a very accurate hole in. I can't mount it in a 4j, and I dont have a mill. I can, however, get it mounted to the cross slide. The easiest solution would obviously be to mount a boring head in the headstock and do it that way, but I don't have one. I do have boring bars and a 4 jaw, so i'm thinking I can use that to dial in an offset. Does anyone have any experience with this, or any suggestions for me? Hole is about 1.375" for reference.
    This would work but the chuck screws are not really calibrated in travel so you will have a tough time of it. Buy an inexpensive boring head with a straight
    shank and put that in a collet. Numbers on boring head, *are* calibrated for travel.

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    If you try this, use a boring bar with a movable bit. Make you an adjustment fixture like jockotheveld did in this post.

    It will take time, but you can accurately move your bit to sneak up on your final dimension.

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    What they said, but with a caveat.

    You are re-inventing the "HBL" or Horizontal Boring Lathe, a stock Niles Tool Works critter in the years between the US Civil War and 1900, "HBM" or Horizontal Boring MILL taking over already and thereafter, up to still-yet-today.

    This will work BETTER if you can run your boring bar clear through the part, support it on center, RUN it on-center, and do your hole sizing with an offset attachment and/or tedious-tiny moves of the toolbit.

    Boring heads, such as the two sizes of Chandler-Duplex I favor, have a ton of "stick out". If you cannot support BOTH ends, a naked boring bar can be shorter and stiffer, tedious adjustment worth it.

    Not to forget, a South Bent utralight airliner or kid's dog or pony cart - wotever the market niche it was aimed at - just ain't the best all-around mount to saddle for single-ending a bore in any case.

    Iron Deficiency Anemia thing. Even if the spaghetti for its bed is made from enriched wheat flour, you run the risk of unwanted taper.

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    Look--you can make almost anything work on a lathe IF you're careful you don't set yourself up for injury or to damage the lathe. What you propose should work just fine if you realize the problems you might have with flexing of the boring bar. You'll probably require a lot of fine cuts to allow you to "sneak up" on the final dimension. The boring tool in a mill boring head isn't supported any better than you can support it in a 4-jaw chuck. You should have success but be careful!

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    faceplate.
    you can even take the jaws out of your chuck and use the slots to rig something up.

    not sure if thats feasible for your particular piece...just a thought.

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    Quote Originally Posted by iwananew10K View Post
    faceplate.
    .. about four feet in diameter. Wedge-shaped flame-cut steel plate bolted flat to it hung a compound rest borrowed off a pre-War One Niles lathe built "City of Allegheny" PA a tad further out.

    Common Armstrong/Williams in classical lantern toolpost and go to cutting stick-weld build-up off a 46" diameter ring about 4 1/2" tall for a Timken bearing, body of a 100-ton crane set on its side, lined up good, beams holding it stick-welded to Ells on the Tee-slotted table.

    Table didn't move when in the cut on a Niles Tool Works boring lathe of that age.

    The spindle was an advancing quill about 11" in diameter - sorta like a drillpress laid-over.

    Two places the operator could choose to stand. A step plate in the casting fore side or rear side, just back of the faceplate. ISTR there were three steel steps up to the catwalk along each side of the headstock that led to those exalted thrones of honour. Or messy suicide. Take yer pick. It was still a free country back in the day.

    The handwheel feed was about the size of the quartermaster's helm on a War One "four stacker" flush-deck US Navy destroyer.

    Pick the back side step, eyeball the compound coming up, reach out, match speed, click in a thou on the dial. Ready for a pass.

    Now advance that quill by hand steady as can be, at around 6 RPM 'til you've traversed the 4+ inches. Retract, power-down. Go get the other hand assigned to hold the far-end of a 60-inch B&S vernier caliper and take the measure.

    Lather, rinse, repeat each 8-hour shift for three days, hit the mark dead nuts, and fit twelve thouand 1963 dollars worth of REBUILT Timken bearing.

    Tell yah one damn thing. Foreman George Armstrong "the Eagle" never said a word to me about HOW, just gave me the print. He also never said another f***king word about my walking in the door three days earlier, the only mic to my 18-year-old name a B&S zero to 3/8".

    Virgin no longer, he just sent me off to an 8-foot Niles VERTICAL Turning Lathe to make the fool hold-down ring. Gravy job. "virgin" plate, no corn-cob stick-weld.

    Which wasn't the same piece of cake, even so, given it was thin enough "relatively" to need a reglar Stonehenge on steroids of studs to keep it flat whilst a slope and step was cut into it by hand and eyeball and vernier. Micrometers were, after all, clearly meant only for "small shit". Felt CHEATED the other two shifts worked on that one. Time I came back, second day, the bugger was done.

    "Outsourcing to low-cost labour China" being as close as barefoot-poor West By God Virginia those days?

    Well... OSHA weren't around, but I figure they'd have shit fired red clay brick enough retroactively to have duplicated Philahooliga's Independence Hall had they only known what we did every day all day with what and how!

    Union shop, too, and proud of it. "Featherbedding" was where you shagged yer lady. Everybody just worked when on the clock.

    Yah wanted a USWA Steel Worker to "strike"? Yah hadda go up the road to Pittsburgh. Where they had earned enough money to AFFORD that silly shit and still eat.



    End of the day? It's only steel. It's all "relative". Person could do this s**t on a Levin or a Derbyshire just as well as on a Niles Tool Works dinosaurian as might have seemed already old when Adam still had hair and Eve still trusted snakes.

    Even a Southbent can do it, operator don't chicken-out.


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    I've used a boring head in the spindle of my Heavy 10 and it worked fine.

    My only concern with the proposed operation is whether the four jaw Chuck has enough travel. You don't want to move the boring bar so far of center that its only held by two jaws. (If you must I think you could add a small v- block and grip that with the other two jaws.)

    It doesn't matter that the chuck jaws are not marked for travel. You can measure the movement of the tool with an indicator. If you choose to use a bar with any adjustable tool bit you can mic the bar plus the tool extension and adjust from there.

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    Quote Originally Posted by fciron View Post
    If you choose to use a bar with any adjustable tool bit you can mic the bar plus the tool extension and adjust from there.
    Prezactly. Our king of the 5" bar (the others were but 3") did this every shift, many times to the hour in boring - for example - gearcases for mining machinery.

    Mind - twenty or thirty years at it, he may have made it look easier than it actually was - I did only get three days of his serious-useful training.

    But the con-cept didn't make yer brain sweat even as much as a fat lady climbing into the upper bunk of a Pullman sleeper car.


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    I've seen the set-up in old books, but don't have any scanned images. IMO it was an option around the turn of the century for engine shops to use a large lathe as an HBM in a pinch. It's one reason why bigger lathes have T-nut slots on top of the saddle. I've always wanted to do it, but also get the impression that it's in the same league as using a milling attachment on a lathe. It works fine but is limited in capacity and isn't near as easy as doing the same job on an appropriate machine. That said, The actual boring motion in Z should be the easy part, but I think the biggest hassle is setting your X-Y position as it's all in how you set-up the part. It'll be along the same lines as boring a hole in a precision location using a standard drill press.

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    A piece of bar stock held in a 4jaw and a boring bar coming from that allows the side jaws holding the bar centered and the up and down jaws adjusting size.. The last fine adjustment can be micrometer over the held bit.. or moving the whole bar under an indicator...perhaps for .0005 with a sharp bit.
    This bar can also hold the indicator to tram the part.

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    Thermite,
    You should write a book.
    Seriously, I'd buy it.
    With pictures of the old shops, please.


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    Should have known Harold Hall would have valuable information on his website! Looks like he's done this exact thing, but he held the boring bar in a square block and had the square block in the 4 jaw, to keep a better grip on it. Looks like it's probably the way to go.

    Special Quadrant for a Myford S7 with gear box 02

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    A lathe can be thought of as pretty much a vertical mill or tiny HBM laid on it's back. And you'd have to have a fairly large mill to equal the tool holding rigidity even a 9" - 11" South Bend lathes head stock will have. I searched for and bought my last lathe due to it having an important feature I wasn't willing to do without. A tee slotted cross slide. As long as any hole C/L falls within the part edge and the head stocks C/L I can drill / bore it by setting the part elevation on spacers and clamping it down, or use a good heavy milling attachment. While I've got shanks that fit my head stocks MT and either of my boring heads or the B&F head, but if I didn't have any of that? I've bored holes with a lathe by using a specially sharpened (for cutting tool edge clearance)lathe tool in a shop made fly cutter body and setting it's final diameter to the finished hole size with a dial indicator. It just takes longer and is a bit fussier to set up than with the better and more sophisticated tooling. A boring bar locked in a tool block and used on a 4 jaw or even the face plate and again set with that indicator as others have said will do the same. For some tooling and I'd use machining the G.H. Thomas versatile dividing head castings as a prime example, you want the tools spindle C/L that your machining exactly the same as the lathes head stock C/L. So even having a vertical mill you'd still chose to do the finish boring on the lathe.

    There is an even better and still fairly cheap method for through holes above 3/4" - 1" diameter or larger and work mounted on the cross slide. A between centers boring bar. It's an extremely accurate and much more rigid method than any proper boring head and a well proven technique used with HBM's on high precision work. For some reason few in the hobby seem to want to spend a few bucks and have at there finger tips some of the information available that was specifically written for people like us. One book that would directly relate to this thread would be https://www.teepublishing.co.uk/book...rkshop-manual/ and directly ordered from that location in the UK since it will be much cheaper than the re-seller bandits on Ebay want for the exact same thing. The design within that book for a between centers boring bar is worth the price of the book all on it's own. And there's a hell of a lot within it's two covers that's well worth learning for high quality and precision machining.Even more so for those without a mill. I doubt few professional machinist's couldn't pick up a trick or two from it.


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