What's new
What's new

How to sharpen a reamer?

tjd10684

Cast Iron
Joined
Jan 26, 2011
Location
PA
Ok some of you know from my other threads that I offer a service where I ream out PB barrels to accept a barrel insert of various sizes. Anyhow reaming thru that layer of anodize is killing my reamers. Right now I am using HSS reamers since they need to be really sharp problem is they dont stay that way long. I have tracked the use of my latest set of reamers and I get 15 uses before I start seeing issues. I am sure that I can get about 10 more good uses out of them but each time I have to baby the cut more and more (clear chips more often more lube generally more time per unit). So I am thinking about sharpening them in some way so that I can get more uses before scraping them. The main reason I am thinking about sharpening them is because the final reamer is kinda an odd ball size and is rather expensive to keep re-ordering (0.745 DIA). I am not too concerned about the tenths that I will loose by sharpening I can loose up to 0.002 before their is any real issue with the hole being too small. So the question is how would one go about doing this? I figure there is a couple options

1. do it manually the old school way (I would have to learn how)
2. Buy some kind of sharpener like a darex (do darex sharpeners do reamers?)
3. Find someone who can sharpen them for me and put them on a rotation
4. Keep with the status quo and keep buying them new.


So does anyone have some wisdom they would like to pass along? And thanks in advance.
 
I am a little surprised you get even that much life,cutting through anodizing (Al2O3)

Why not use carbide reamer?

I have sharpened a lot of adjustable blade reamers with a regular flat bench stone, but they are adjustable so I do not worry about size. Hold the reamer in the (padded) vise, stone the relief face until the wear land is gone.
 
A machine reamer (!= hand reamer) normally is only sharpened at the face (at the 45° bevel). The rest is (almost) cylindrical.
You would need a T&C grinder. Could be a basic one. Looks like turning between centers, a dog, and some means to index to the flutes (or a finger). Plus a grinding head that can be adjusted to the 45°.
On reamers, the flutes sometimes are NOT evenly spaced. That prohibits indexing them. Would require a closer look.

Or send them to a professional grinding service. Should cost less than new.


Nick
 
Reamers are re-sharpened on the bevel at the end, which is where the cutting action takes place. It is not usually needed to grind the OD unless you want to make the reamer smaller. I have a Darex TR70 tap, countersink and reamer sharpener, but I think they stopped making them years ago. I think you can still get a new SRD/TDR 82-R sharpener that does reamers, endmills and drill bits. Both the TDR and the Darex were very expensive when bought new.

http://www.drill-grinder.com/storefront/Scripts/prodView.asp?idproduct=18
http://www.darex.com/images/stories/manuals/TR70Manual.pdf

Once you understand the method of sharpening, you can build a fixture for use with a grinder with good bearings. A surface grinder can be adapted, for instance. If the reamers have six equally spaced flutes, start with a six-side 5C collet block. A 5c spin-indexer can also do eight or twelve flutes.

I wonder if there is a chemical means of removing the anodizing from the bore only. I know anodized cooking pans will lose their coating if washed in a dishwasher. Maybe there is a common chemical that will do the job quickly, like drain cleaner (lye).

Aluminum oxide will dull carbide tools, but probably more slowly than HS.

It should be possible to hand sharpen the bevels on your HSS roughing reamers very quickly, and probably it wil be plenty good enough to get through the anodizing if the diameter is large enough. Maybe one flute will do all the cutting, but it is so easy to regrind that it would not matter. Once the anodizing is gone, your finish reamer should last for many jobs, and that is the one to send out to a pro.

Larry
 




Here is an up close look at the cutting edge of one of the dull reamers I believe this is the finish reamer. I will see if I can get some similar pics of the roughing reamer.

Why not use carbide reamer?

two reasons 1. I cant find one through my normal suppliers 2. I'm kinda scared of trying to sharpen a HSS reamer I dare not think about sharpening a carbide (ya I'm a sissy when it comes to carbide) I do however appreciate the input.

I wonder if there is a chemical means of removing the anodizing from the bore only. I know anodized cooking pans will lose their coating if washed in a dishwasher. Maybe there is a common chemical that will do the job quickly, like drain cleaner (lye).

Yes I could remove the anodized layer chemically but its not really a selective process. At least not without a lot of prep work time that would cut my profits to just about 0. Also most of the barrels I do are color matched to the rest of the marker so you cant strip the anodize bore and re anodize to color match especially some of the one of a kind markers out there. My best bet is to just cut thru it and deal with the consequences such as dulled reamers

It should be possible to hand sharpen the bevels on your HSS roughing reamers very quickly, and probably it wil be plenty good enough to get through the anodizing if the diameter is large enough. Maybe one flute will do all the cutting, but it is so easy to regrind that it would not matter. Once the anodizing is gone, your finish reamer should last for many jobs, and that is the one to send out to a pro.

I am most likely going to try this on one of my dull sets. Then try it on some "practice" barrels I bought a while back before trying it on a customer barrel. The concern I would have here though is I made a jig that lets the barrel self align to the reamer. It works very well but the stipulation is you can't push the barrel to one side or the other the cutting forces need to be balanced to keep everything cutting true at the bottom of the bore. For the record I am reaming to a depth of 5.100" and I am looking for the ream to be concentric to the original bore to within 0.001". I know that I am not getting this every time but hey aim small miss small.

scaled.php


These are the kind of barrels I am reaming notice the taper on OD of the barrel this keeps me from being able to put it in a regular chuck , even a 4 jaw. So I made a jig like this.

scaled.php


Hopefully this extra information gives a little more context to the operation and why I am doing it the way I am.
 
At my first job we reamed a lot of holes in tough materials (316 and titanium), with many of the same issues you're suffering from. We then switched to boring with a carbide insert and the problems went away.
 
Hello
The anodising layer is very thin so why not grind it off.
I have made flapper wheels using pieces of cloth sanding belt threaded through the strands of a piece of 6mm dia wire rope and glued in place.

Make the wire rope long enough to fit in a chuck and extend down the barrel. I use epoxy glue to hold the abrasive pieces onto the wire.
Wrap a strand of wire around the end of the rope to stop the belt pieces spreading the rope strands while the glue is drying.

The original version I made to allow me to grind smooth the bore of a cast aluminium engine intake manifold. I now use it to descale tubing.
The wire provided a flexible drive that allowed me to get around corners that would have been impossible to access with a solid shanked tool.

For your application I would use the flapper on a hand held electric drill and just run the grinding end up and down the bore until the anodizing is gone.
Your reamers will then only need to cut aluminium and should last forever.

Regards


Dazz
 
A set of soft jaws, machined to suit, would take care of your work mounting issue.

Is enough material being removed to allow a first pass with a tool that just removes the Al2O3? A piloted spade bit, perhaps carbide or even M2?

Just ideas,

I would just resharpen, but I do have a T&C grinder.
 
I would use a carbide reamer to cut through the anodize and a HSS reamer to finish, if you have enough material. One problem that hasn't been noted is that once the cutting edge is dull, the aluminum oxide will wear on the OD, making it tapered. Once this happens, the reamer is probably junk.

I would not consider hand sharpening a reamer, if you want it to cut to size. If you don't have grinder, I would find a reliable sharpening service for both carbide and the HSS.

Tom
 
A set of soft jaws, machined to suit, would take care of your work mounting issue.

Is enough material being removed to allow a first pass with a tool that just removes the Al2O3? A piloted spade bit, perhaps carbide or even M2?

Just ideas,

I would just resharpen, but I do have a T&C grinder.

Thanks for the ideas unfortunately the picture show is the exception rather than the rule. I have done maybe 30-40 so far except for that picture I have not had to do more than 1 of any particular make model year. so in theory I would have maybe 25 sets of soft jaws (I am sure I could reuse a couple) by now. I know that eventually that would start to die down but it would be a while.

as for material being removed. typically I am starting with a bore of ~0.690 and I am opening it up to 0.745 (in 2 steps) so ~0.055 not sure that is enough or not? My other thought was just a regular drill but I would be concerned that it would have a tendency to pull the work into the drill maybe?

Thank you all so far for helping me out.
 
Yes and would bet the flex hone guys have dealt with this problem
be worth a call
mike
you mean to remove the anodize layer prior to reaming? I do have a ball hone that I use for finishing (600 grit) maybe a more aggressive one to break up the anodize layer first humm looks like I have a second experiment to try.
 
.055" seems like 2 healthy reamer cuts. Carbide to clean it, hss to size it.

OP- what again is the purpose of the liners? I know you've stated it before, but I've drank since then. Lol
 
what about countersinking to just over the finish ream size, then push the reamer in? maybe that would keep the cutting edge of the reamer from ever contacting the anodized surface, or at least initially. You know, just keeping the cutting edge buried in aluminum
 
if your not running coolent, how about flushing with air to get the anodized chips out of the cutting zone asap, but i like the abrasive idea, scotch brite would do this.
 
I can almost guarantee that you won't be happy with a hand-sharpened a reamer.
But it can't hurt if you try it on a dull one.

I've hand sharpened many many reamers. With very good results. On a POS $25 belt sander no less.

It surprises me damn near daily what the human eye can perceive. A little practice and you're good to go.
Really what do you have to lose? Give it a shot, see how it cuts, if you get the sharpening too deep, chop
a bit off the end and start again.

In reality a reamer is an insanely simple cutting tool. There really isn't any fancy cutting angles or reliefs, or even
large cutting edges. Touch 'em up on the belt sander, You're just touching it up. A few tenths maybe. When I do it,
I just touch 'em, figure out how you need to hold it so that you don't destroy a flute you're not working on, and then just
touch it, that's all it takes. I also hit it on the part of the belt that isn't backed up by anything, so the belt mostly takes
on the shape of the tool.

Actually if you're a bit freaked by the belt sander thing, you could probably touch it up by running a fine stone or diamond
file up the flutes which would keep the geometry in tact.
 
what about countersinking to just over the finish ream size, then push the reamer in? maybe that would keep the cutting edge of the reamer from ever contacting the anodized surface, or at least initially. You know, just keeping the cutting edge buried in aluminum

What I have noticed on the "roughing" reamer is what looks like slight knicks after reaming a couple barels of the same size. I think the part of the reamer that is "in" the metal is usually ok but where the cutting edge transitions out of the cut thru the anodize it seams to wear much more. I hope that makes sense cause it did in my head.

.055" seems like 2 healthy reamer cuts. Carbide to clean it, hss to size it.

OP- what again is the purpose of the liners? I know you've stated it before, but I've drank since then. Lol

paintballs shells are gelatin biased (like liquid Advil capsules) so the size of paintballs can vary due to temperature humidity or other environmental changes. While all manufactures produce nominally 68 caliber balls once they have traveled across the country sat in a warehouse for a while and then in the sun all day they can change size by up to 0.010-0.015. That number can change from box to box even in the same day. So the liners or Freak inserts have slightly different sizes to accommodate these changes. the main manufacturer of these inserts or liners makes them from 0.675 all the way up to 0.695 in 0.003 increments.
 




Here is an up close look at the cutting edge of one of the dull reamers I believe this is the finish reamer. I will see if I can get some similar pics of the roughing reamer.

Why not use carbide reamer?

two reasons 1. I cant find one through my normal suppliers 2. I'm kinda scared of trying to sharpen a HSS reamer I dare not think about sharpening a carbide (ya I'm a sissy when it comes to carbide) I do however appreciate the input.

I wonder if there is a chemical means of removing the anodizing from the bore only. I know anodized cooking pans will lose their coating if washed in a dishwasher. Maybe there is a common chemical that will do the job quickly, like drain cleaner (lye).

Yes I could remove the anodized layer chemically but its not really a selective process. At least not without a lot of prep work time that would cut my profits to just about 0. Also most of the barrels I do are color matched to the rest of the marker so you cant strip the anodize bore and re anodize to color match especially some of the one of a kind markers out there. My best bet is to just cut thru it and deal with the consequences such as dulled reamers

It should be possible to hand sharpen the bevels on your HSS roughing reamers very quickly, and probably it wil be plenty good enough to get through the anodizing if the diameter is large enough. Maybe one flute will do all the cutting, but it is so easy to regrind that it would not matter. Once the anodizing is gone, your finish reamer should last for many jobs, and that is the one to send out to a pro.

I am most likely going to try this on one of my dull sets. Then try it on some "practice" barrels I bought a while back before trying it on a customer barrel. The concern I would have here though is I made a jig that lets the barrel self align to the reamer. It works very well but the stipulation is you can't push the barrel to one side or the other the cutting forces need to be balanced to keep everything cutting true at the bottom of the bore. For the record I am reaming to a depth of 5.100" and I am looking for the ream to be concentric to the original bore to within 0.001". I know that I am not getting this every time but hey aim small miss small.

scaled.php


These are the kind of barrels I am reaming notice the taper on OD of the barrel this keeps me from being able to put it in a regular chuck , even a 4 jaw. So I made a jig like this.

scaled.php


Hopefully this extra information gives a little more context to the operation and why I am doing it the way I am.

I know pics can be misleading, but how fast are you running that reamer?
 








 
Back
Top