??? Reamer Holder ????

Discussion in 'Gunsmithing' started by bigngreen, Jun 12, 2010.

  1. bigngreen

    bigngreen Well-Known Member

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    OK, I've read everything I can find on the internet about reamer holders so now I'm in need of more help than I was before!:D

    Here's what I'm know so far, I need some kind of reamer holder, I want to get or build a quality one as I don't like screwing around, do it once do it right!

    I have gone over the lathe that I'm using and I'm thinking the best thing for me to do is to get a 3MT tool holder and chamber with the tool post instead of dealing with the tail stock which is way out of wack. I used a ground rod and put it into a tool holder and centered it to the spindle bore then moved the carriage several inches and I could see no movement on a .001 dial indicator, so it looks like it's movement is real good to me. By the way I have a .0005 test indicator en route.

    Any links or advice would be greatly appreciated!
     
  2. J E Custom

    J E Custom Well-Known Member

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    I would recomend using the tail stock because most reamer holders use the tail stock.

    You need to correct the tail stock anyway . I had the same problem and bought a precision
    alignment bar 1"x 12" from PTG and straightened the tail stock.

    I am sure there are some that use the carriage for chambering but I like to use the tail stock
    And as I said it needs to be centered/aligned anyway.

    Just my opinion

    J E CUSTOM
     

  3. shortgrass

    shortgrass Well-Known Member

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    I have found, over the years, that there is not too much that hasn't been tried, at one time or another, when it comes to gunsmithing. I suspect there's a reason why most use the tail stock. It seems the natural way to do the job (the end slide or tail stock). I never remember using a 'round' tool mounted on a 'side' slide, in the years I worked in job shops, not that it couldn't be done on the right machine, I guess. I'd make sure the lathe is level (with an engineers level) and then straighten out that tail stock. That's part of owning a machine, knowing how to adjust it when it gets 'out of wack'.I know, it takes time, but, you'll want to use that tail stock for other jobs too, and it will need to be true to the spindle. And, you will learn more about your lathe in the process. No need to over complicate what should be a straight forward machining operation. Think about it for a minute,,,,,, if you are going to make a reamer holder the tail stock needs to be trued to the spindle anyway! Just my 2 cents
     
    Last edited: Jun 13, 2010
  4. Fitch

    Fitch Well-Known Member

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    This is a shamless copy of some I saw on one forum or another, or maybe more than one. I'm not sure who made the first one or I'd give them credit for it right here. The bottom line, it was free because I made it out of metal I had in my "metal archive", and it works essentially perfectly for chambering barrels.

    This piece in the tail stock pushes on face of the collar that holds the reamer. That face of the collar that holds the reamer was machined in the same setup where the center hole was bored so the plane of the collar face is dead nuts orthogonal to the bore axis, which means it is also as perfectly orthogonal to the axis of the reamer as I can practically make it. I made a collar instead of a tap holder type because I couldn't see any way to guarantee both faces of the tap holder were in exactly the same plane, which as is discussed below, is key to how a pusher like this functions.

    The pusher itself is a piece of mystery metal, from a drop rack in a metal yard far away, machined to have a MT #3 taper on the back end. This was then put in the headstock of my 9" SB, parted, faced and drilled out 29/64". The important point is that the plane of the pushing face is dead nuts orthogonal to the axis of the pusher. As will become evident, this is key to why it works well.

    [​IMG]

    While I've seen the pictures, I've never seen an explanation of why this design works so well, so I thought about it a while before I made this one. I wanted to machine it controlling as exactly as I could what ever the critical parameters were that made it work. I came up with the following hypothesis to explain why I think it works as well as it does.

    It, and the Manson my friend the "real" gunsmith with the borescope has, work on pretty much the same principle, and tend to create forces that react against the pilot to drive the back end of the reamer in the direction to correct for parallel axis misalignment between the spindle centerline and the reamer centerline.

    My tail stock ram CL is right in line with the lathe spindle front to back as close as I can measure it. It is about 0.002" high with the tail stock clamp torqued down as tight as I can reasonably get it using the handle it came with (I plan to take it apart and weld a square drive socket on it so I can use a torque wrench - but it won't get any closer even with a cheater bar, I tried, but didn't over do it). The important part is that the tail stock spindle axis is "parallel" to the spindle axis, but offset ~0.002" above it. This parallel offset is probably found to one degree or another on most of the lathes used for chambering. That being the case, if the reamer is pushed square to the axis it will self center parallel with the lathe axis.

    Why will it self center?

    If you had a pencil lying on the desk with a cross stick glued to it, you could push it with two fingers and it would stay pointed in the direction you are pushing. If you push on the eraser with one finger, when the pencil gets a little off line, it will tend to go further off line.

    The first case applies to this and the Manson pushers. The pushed surface on the collar is orthogonal to the reamer centerline, and the push surface of the annular ring that does the pushing is orthogonal to the tail stock centerline. If the reamer tries to tilt out of parallel with the centerlines, the ring acts on the side opposite to the direction of tilt and tries to push it back to parallel. This moves the back of the reamer to stay in line with the pilot so it remains parallel to the spindle centerline.

    Even though a reamer cuts on the side, it seems to want to be inherently self centering on the bore left to it's own devices. My theory for thi is that for small deviations from parallel with the bore, the reamer presents a greater frontal area off set on the side in which it is out of alignment. This greater frontal area will tend to react against the pilot to push the back end of the reamer back into into alignment with the axis of rotation. This correcting force from the front of the reamer is apparently stronger than the destabilizing force from the offset push at the back, (for small deviations - it isn't for large ones), so within limitations of small deviations it overcomes the inherent instability of the pushing scheme. And that is why I think the Bald Eagle reamer holder works (and I proved to myself that a pusher based on that principle does work just fine) inspite of the inherent instability of it's design.

    With the correcting force from the front of the reamer, and the inherent correcting force on the back of the reamer from the annular (or planer in the case of the Manson unit) pusher, the reamer should follow right along a path parallel to the lathe axis if the bore is centered on the lathe axis. This emphasizes why it is so extremely important to have very precise bore alignment with the spindle axis in the area where the chamberi is being cut. This may seem obvious but it is important because it means the floating holder will "not" compensate for the bore being misaligned with the axis, on only compensates for the reamer being misaligned with the bore.

    Given the principles involved I could have made the annular pushing surface larger in diameter (keeping the center hole the same size - 29/64" for a 7/16" reamer shank) but it seemed to me the increased surface area might somehow add friction to the system, make it sticky, and impede it's operation, so I didn't do that. As it is, it works just fine.

    I've seen no indication that I need to add a second handle on the other side to maybe get a more symmetrical torque reaction, but I could do that if I had to. I didn't use shoulder bolts in the collar and slots in the pusher for torque reaction like the Manson holder has because I think that if the bolts and slots were not precisely aligned on a diameter that would tend to push the reamer off center. I wasn't sure how to do that as precisely as I needed to so I stuck with the handle.

    Finally, when I hold the handle my thumb is right over the set screw that is tightened on the reamer, my fingers under the handle to resist torque reastion. This "grip" effectively eliminates side force because it is a torque couple. You can demonstrate this to your self if you use a long extension on a socket wrench. If you just pull on the handle the thing will move sideways. if you put your thumb on the rachet head and counteract the finger pull on the handle you can apply torque to the wrench with no side force. That's how I hold this reamer holder. It works just fine and the torque couple is why.

    In know, I know, I'm putting some to sleep, and others think I'm regrinding flour into molecule sized dust particles (the smallest particles that are still flour), but I like to know why things work. I don't seem to be able to resist trying to figure things out. My engineering gene made me do it.

    That's my story and I'm sticking to it.

    Let me add, I've no indispensible ego attached to any of this, I'm just looking for the truth of it, so if you have a different view of the physics at work, please share it.

    Fitch
     
  5. bigngreen

    bigngreen Well-Known Member

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    Thanks for the replies guys!!!! Double that for Fitch, I hope your fingers stop cramping soon :D:D

    The was a great write up, I'm very inclined to make a holder/pusher like you have. I like real clean and simple things as they usually work the best. The extra why it works and how it works really helps.
    The reason I want to use the tool holder over the tail stock is that I get .004 of up movement in a 4in movement of the tails stock spindle. I have also check how repeatable it is and I'm not liking it, granted it is probably better than I think and I'm being nit picky.
    My other reasoning is the fact that when I was building my action truing jig I was able to turn the outside and bore the inside very accurately, actually surprisingly so. So why wouldn't I want to use the most accurate, repeatable means of holding a reamer that I'm trying to run perfectly down the barrel? I check the repeatability of the carriage to come back to an exact position by recreating the movement that would be happening with removing the reamer,cleaning and lubing then going back and take another cut and I was able to easily return to that spot with accuracy that I couldn't even see on my .001 indicator.
    That and I think Chad Dixon has said a couple times to do it with the tool holder. This may not even require a floating holder but an adjustable fixed holder.
    I'll tinker with it more today!! A lathe is one of the best big boy things ever :D:D
     
  6. J E Custom

    J E Custom Well-Known Member

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    Very good information.

    I took a different approach (One of many) and instead of building a different Mouse trap I
    just fixed the one that I had, by truing the lathe with as near perfect alignment as possible.
    with the instruments on hand ,(they read to .00005) I have been very happy with the
    Manson reamer holder.

    I have found that the tail stock requires consistant torque to reach zero. (It always started
    out .001 to .002 thousandths high)until I found a torque value that brought it in perfect.

    Sense aligning the tail stock, chamber run out has been immeasurable using the Manson
    reamer holder. also there is another one that uses a ball socket but I dont know much
    about it I think Specweldtom has one and maybe he can add to this post.

    I make a lot of my special tools also but this one worked so well I decided to go with it,

    It is a very good place to start if the lathe is true.

    Just some more information.

    J E CUSTOM
     
    Last edited: Jun 13, 2010
  7. Fitch

    Fitch Well-Known Member

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    Thanks guys.

    While I'm at it I should include some critical data on the pusher and how I use it.

    The hole in the pusher in the tail stock is about .020" larger in diameter than the reamer shank and deep enough that the end of the reamer won't bottom in it. I didn't want anything but the front face to contact the reamer assy. This gives me enough play to accomodate the hight variation between my tail stock and the spindle, yet limits the reamer's movement which makes it easier to get it started.

    I feed with the tailstock wheel and use a dial indicator mounted like this to watch the depth:

    [​IMG]

    I've found that by doing some "practice landings" where I use the go gage, pick a new depth, mic it, then try to hit that new depth using the dial indicator, I have no trouble hitting the mark within the line width on the indicator face, and it will mic at the desired depth will within half a division.

    Making cutting passes:

    I can feel the torque and regulate the feed to keep it smooth - holding the reamer handle in my left hand, turning the tail stock feed wheel with my right hand. Normally the feed is smooth, there is no jerking to speak of, and I can easily regulate the feed to maintain a constant torque. I can tell essentially instantly if anything is amiss in the chamber. The one time I had chatter begin to start I was able to immediately let go of the handle, back off the tail stock, turn off the spindle, clean the reamer, relube it, and use a couple of patch restarts which corrected the chatter problem before it turned into a real problem. Chatter won't self correct, it will just get worse.

    When I see chips show up, or I've gone about .025" in depth of cut (which ever come first), I let go of the handle, back off the tail stock quill enough turns (the same every time) to clear the reamer shank, turn off the lathe spindle, and remove the reamer. Letting go of the handle and letting it spin avoids galling from a chip getting under a reamer flute that might happen if I tried to remove the reamer with the spindle still turning. Removing it with the spindle stopped makes that a complete non issue.

    Note: It's important to have a short enough handle that it can spin clear of the cross slide and compound if the compound is in place when chambering. Mine is.

    I use the lathe carriage as a tail stock stop - i.e. I position it against the tailstock and tighten the clamp to lock it in place when I know where the tailstock is to be located. That way I can pull the tail stock back after retracting the tail stock spindle half an inch or so and withdraw the reamer straight out of the chamber and easily move the tailstock back to the same location.

    Once the reamer is out I use a rubber tipped air nozzle to blow the chips out of the chamber (and look in there to be sure they are gone), rinse chips off the reamer in a container of paint thinner, blow it dry with compressed air, dip it in the cutting oil, and reinsert it into the chamber. Then I run the tail stock back up, clamp it, then advance the tail stock quill with the hand crank to get it back over the shank of the reamer. I can tell from the dial indicator almost 'exactly" when the reamer will start cutting again. When I'm close I start the spindle and begin the next cut.

    Fitch
     
    Last edited: Jun 13, 2010
  8. Fitch

    Fitch Well-Known Member

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    A lathe is one of the best big-boy toys for sure! I sure have enjoyed playing with one on a hobby basis for the last 60 years (I started on the 9" South Bend Model A that is still in my shop under my Dad's supervision when I was 8).

    Chad is very very good at what he does - IMO as good or better than the best on the planet over all the processes associated with rifle building from muzzle to buttplate. With his lathe he doesn't have a choice, he pretty much has to use the tool holder on that really nice CNC lathe of his - I don't think it even has (or needs) a tail stock. One doesn't want to have their fingers anyplace near one of those things so it has to work with the door that has the bullet proof glass closed. He needed a holder that he could use with the door shut. And he has worked out how to do that with out compromising quality or accuracy in any way.

    That said, while it absolutely can be made to work on a manual lathe, I'm not sure that's the best way on a manual lathe. It might be, but I'm not sure of that. I may try it one day just to see how it works. One could use a pusher like mine feeding with the carriage aligned using Chad's alignment procedure, or a Manson Holder (which I think is a good tool, it just cost more than the one I made for a bit of time invested), or the holder that Greg Tannell sells (much like the one Chad made). If one has a muzzle flush coolant system, which I think Chad uses, his approach might be the method of choice.

    Fitch
     
  9. bigngreen

    bigngreen Well-Known Member

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    Thank for posting more details on you method Fitch, it really helps me get a feel for what I'm going to have going on when chambering and what things will help get repeatable accuracy.

    I've looked at the Bald Eagle holder at PTG and it looks like the same basic concept as Fitch's.
    I have also looked at the Manson holder but can't quite see how it functions in the pic, if anyone is using one I would appreciate a better pic or description of it's function.
    Also looked at the PGS holder I think, I can't find the link now.

    I have been pouring over Mike Bryant's web page, which I have found very good info at. I have also been looking at the Gre-Tan page, he has a reamer holder and a video on getting your tail stock set up right for reaming, it maybe worth the money.

    I should also mention if any one has a take of .277 cal barrel that I could buy cheap for practice let me know, I don't feel good about practicing on a good barrel :D
     
  10. Fitch

    Fitch Well-Known Member

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    The one I looked at my buddies shop is basically two flat disks, one pushing on the other, coupled for torque reaction by two posts. The disk holding the reamer is restrained from turning by two shouldered bolts that screw into the push plate that is in the tail stock. It compensates for parallel misalignment much lke the one I made does. Also, just like mine, it doesn't compensate well for angular misalignment between the tail stock quill and the spindle axis. The parallel misalignment is allowed for by some slop in the slots for the bolts that transfer the torque. I think it's best installed with the bolts vertical because horizontal alignment is easier to atain than vertical on most lathes. If the tail stock is in perfect alignment vertically today, it won't be tomorrow after some wear takes place.

    I liked the design (and cost) of mine better for me, but the Manson and the Bald Eagle have worked well for folks chambering rifles all over the planet. The Bald Eagle retains the "feel" benefits I get with mine but I don't like the inherent instability of it's design. To see what I mean, lay a pencil on your desk. Take one finger and push straight on the eraser. Unless you make corrections with your finger, the pencil will get crooked and then turn clear around as your finger passes it by. The operating principle of the Manson and one like mine are like laying something shaped like the letter "T" down and pushing on it with two fingers an inch or two apart on the top of the "T". The "T" will stay in contact with the fingers and pointed in the right direction - it will self correct for disturbances that want to make it change direction because the finger on the side it tries to move to will push it back in the other direction.

    That said, I did chamber my first barrel (a .22-250) using a poor man's Bald Eagle pusher, I was pushing on the back of bolt stub machined round and screwed into the back of the reamer with a flat surface held in the tail stock while I restrained it from turning with a sawed off (so it could spin freely if it had to) end wrench, and the chamber came out just fine. So an inordinate fixation on perfection in the pusher doesn't seem to be warranted. As long as you align the bore with the lathe spindle axis and don't force the reamer to go someplace else by pushing on it with a dead center in the tail stock, it will pretty much do what it should.

    There are three reamer holders that make sense to me. The Bald Eagle, one like I made (the least expensive), and the Manson. I didn't like the concept behind the GreTan holder which, as I understand it, has no built in compensation for parallel misalignment so I didn't persue making one like it. It apparently works great if you have your tail stock perfectly aligned and it holds that alignment as the quill is extended. I don't, the quill on my lathe's tailstock doesn't, and can't be reasonably made to do so, so I don't use it or one like it.

    Good idea! Good candidates for finding used barrels are benchrest shooters, especially those shooting barrel burner calibers like 6.5-284. I picked up a used A&B barrel chambered in 6mmBR for $40.00 to use for practice. I sawed off the chamber, rechambered it from 6mmBR to .243Win and put it on a Savage Model 10 that had an awful factory barrel with the idea that it would be a throw away barrel.
    It shoots so well I've not been able to make myself take it off the rifle! It's my backup chuck gun for windy days or long fields when/where the .17Rem won't work so well.

    Last week I picked up a used Bartline 6mmPPC barrel for nothing that I'm going to rechamber for practice during shop season this winter. I'm thinking of making it into a 6x45 just for fun.

    You have a real thrill in store for you when you chamber your first barrel and it shoots bug holes. Gets the heart rate right up there it does. Combining lathes, shooting, and hunting, is about as much fun as one can have.

    Fitch
     
    Last edited: Jun 13, 2010
  11. specweldtom

    specweldtom Well-Known Member

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    bigngreen, the pusher holder JE Custom mentioned is made and sold by RockJag4 on the 6mmBR (Accurate Shooter) website. I have one of them, and have a 6.5 x .284 chamber to test it on. It appears to have minimal radial float, but looks like it will be very easy to use, and as Fitch said, will give good "feel" on the reamer. I've used a Clymer floating holder, but it doesn't let you feel the reamer torque, so I want to try something that does. In my opinion, the place to start is to get the tailstock quill as perfectly aligned as possible, no matter which holder you use. Mine took 3 sessions (many hours), but is parallel and axial to .0005 in 12". It is .002" high until I clamp it hard on the ways, then that is where the .0005" comes from. I move the tailstock back and forth several times, wiping the ways dry before clamping it down, but it is still .0005" high. I can't consistently work any closer than that anyway, so I drilled, reamed, and installed two # 7 taper pins to lock in lateral location of the base to body joint. So if I need to kick the tailstock off, I should be able to return it to the alignment I have now. I hope.

    I can't comment on using the carriage/toolholder to hold the reamer. Thought of it, but decided to go with aligning the tailstock instead. Good move for about 100 reasons.

    Take a look at RockJag's holder. Simple and well made.

    Tom
     
  12. bigngreen

    bigngreen Well-Known Member

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    Thanks for more good info!! I checked out RockJag's reamer holder and it looks good and the price is right, it's on the short list now!
    I kinda like the idea of just making one, it will help me learn the machine and gain some skills while making useful tools.

    Riddle me this, what surfaces are contacting in the above holder of the Bald Eagle? Is there a flat surface in the reamer side and the round point on the tail stock side that allows there to be movement or is it bearing on the shoulder like Fitch's?

    I know I can get the tail stock aligned horizontally fine but the vertical will be a challenge. To that end it may help if I can get another question answered. Can I set the tail stock in one position, lock it down and just run it in and out to ream and clean or do I need to slide the whole works back. I have 4 in to work with.
    Part of my problem is I don't have an indicator that is fine enough, I should have it this week though so I can measure with some precision.

    I was going to work on the tail stock today but had to work with my other "iron", I picked up a yearling buckskin horse today, he's the first link in my pack string for getting to better elk country. I'm jacked, I haven't worked with a horse before it was big enough to auger me into the dirt, I think I will have good results with this one though :D
     
  13. specweldtom

    specweldtom Well-Known Member

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    It has a ball end tenon on the pusher and a slightly larger ball socket in the back of the reamer holder. As I said, it appears to have very limited (if any) radial float, so your tailstock quill will have to be very close to true with the spindle. RockJag said it has radial float, but I don't see it.

    Don't count on any holder correcting very much misalignment. Too easy to wallow out a chamber.

    Any vertical misalignment should be under .001" when the tailstock is clamped down. I'd be surprised if it's that much. Not much I know to do to correct vertical.

    On moving the tailstock, you probably won't have to move it just to cut short chambers, but you will want to in order to inspect the chamber every so often, and for checking headspace. Then you'll have to unlock the tailstock and slide it back. I believe that Fitch positions and locks his carriage down as a stop for the tailstock. Start out with the tailstock bumped against the locked carriage, and when you pull the tailstock back, you can return it to position by bumping it against the carriage again. I'm going to start doing it. If you use a Manson or Clymer floating holder, and you have only 4" of travel, I think you will end up having to relocate the tailstock, maybe for every cut when you get down close on a long chamber, like a RUM or a big Weatherby. You have to pull the pilot clear to do a good cleaning between cuts. I haven't used the pusher yet, but it might eliminate the need to slide the tailstock back and forth. I don't know yet. In the end though, you will have to move the tailstock out of the way to screw the action on and set headspace made up handy in the lathe.

    I agree with Fitch on doing the work yourself. I hate working on stocks, but the lathe work is a lot of fun (when you get it right).

    Tom
     
  14. Fitch

    Fitch Well-Known Member

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    That sure doesn't sound like a good holder design to me, and I'll explain why I think that.

    The ball tenon in a ball socket won't have radial float which is exactly what is needed to compensate for a high tailstock. You might as well use a dead center into the back of the reamer as a ball tenon in a ball socket. If the tailstock isn't perfectly aligned it will force the reamer off center causing an enlarged chamber. The chamber oversize will in theory be about double the tailstock misalignment - that is not good. Not good at all.

    I agree, if you use the RockJag holder you need the tail stock quill to be perfectly aligned to start and it must stay that way through out its travel. In other words, the tail stock quill centerline must be perfectly aligned, and extension of the lathe spindle centerline. Getting two lines aligned is much harder than aligning a point with a line. It must also come back to the exact same alignment after being moved to clean the reamer and reclamped. Deviations from perfection will be multiplied by two in the chamber diameter. The other bad thing about an oversize chamber is it may allow a thin chip to be trapped between a reamer flute and the chamber wall and gall it resulting in a very rough chamber finish. There is nothing good to be said about an oversize chamber.

    The Manson, Bald Eagle, or one like mine don't require perfect tailstock alignment, that is what makes them useful. The most tolerant are the Bald Eagle and One like Mine.

    That said, it is very important to note that none of them, repeat NONE of them, tolerate or compensate for misalignment of the barrel in the headstock - that needs to be dead nuts every time. (I am a huge fan of Gordy Gritters alignment technique.)

    Every manual lathe I've ever seen comes from the factory with a tailstock quill that is .003" to .005" high on purpose. The reason for that is so it wears into perfect alignment and can take a lot of wear before it goes beyond usefulness below the spindle centerline. They can all be aligned to be centered front to back, the problem is them being high. A pusher that has some radial alignment tolerance will easily handle the tailstock being .005" high. One that has a ball tenon in a socket won't handle any misalignment at all - it's just the same as pushing the reamer with a dead center - just not as sharp if you bump into it with your hand.

    Fitch