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Brown and Sharpe Taper Reamer: Straight shaft w/o spinning between centers.

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Ray C

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#1
Been meaning to re-make a Brown & Sharpe taper reamer, this time out of O1 tool steel that will be heat treated to RC 60+. This is will be used to make balancing grinder hubs for the B&S surface grinder in my shop. The angle is 7.125[SUP]o[/SUP] from centerline (14.25[SUP]o[/SUP] inclusive) which I believe is also known as 3 in 12 taper. Reamers with this angle are available but I can't find one with the right base diameters.

This metal is a little expensive so I'll want to use as short a piece as possible. To do that, I'll pass along a method of spinning between a 3J chuck and a dead center -and still managing to get perfect concentricity. I'll show step by step and it's useful for folks who prefer not to spin between centers. Normally, I would spin between centers but I'm trying to conserve this piece of stock.

It starts out with this, a hunk of O1 and a CAD drawing with the dimensions of the cutter. The cutting edge diameter goes from 1/2" to 1.1" over a distance of 2.4". I've chosen a 2" long shank to drive it and I'm giving myself a generous extra 1.5" of material for work holding in the chuck and dead center. You should be able to see this in the photo below.

BS1.JPG


First, lets see how much room there is and if it's even possible in this little space. Here, I'm taking a piece of old brass boat propeller shaft and seeing if there's enough room to work. After thinking things over, I'm going to splurge and cut my piece 7" long instead of 6".

BS2.JPG

My 3J chuck (just the stock chuck that came with the PM/QMT lathe) is fairly well behaved after some minor tuning and balancing. If your 3J does not re-center well at the same diameter, you should probably switch over to a 4J and scrap your 3J. When a 3J does not re-center at the same diameter, it's got serious problems -probably with the scroll and/or jaw journals.

The trick to this is to always make a mark on the piece and put it in the chuck in the same orientation. Start by facing and drilling one end and making a mark (red spot) that lines-up, in this case, with the insignia on the lathe.

BS3.JPG

When you've done one side, flip it around and face/drill the other end making sure the mark is lined up with your landmark. Once that is done and without removing the piece after the second face/drill operation, I'm going to reduce the shaft to 1/2". This will later be used to grip the part with the 3J chuck. Note: At this time, we know 2 things for sure. 1) the center hole is concentric with the 1/2" stub 2) the 1/2" stub is concentric with the average outside diameter of the uncut shaft. -We also know that the center hole "should be" pretty well centered with the center hole on the other end. Here's the 1/2" stub:

BS4.JPG

Now, flip the piece around and grab it in the jaws by the stub. Bring-in your dead center and tighten things down. Make a light pass of about 0.005 DoC. Then measure the shaft left, center and right. On my first pass, I had difference of 0.0046", wide at the tailstock end. This means that the tailstock must be moved toward me by 0.0023".

The next sequence of steps, to move the TS 0.0023", are important to do in the proper order.
First, put a TDI on the end of the part and set it to a zero point (utilizing 1/2 the travel of the TDI). Second, slightly loosen the chuck jaws so they are still grabbing the piece but not loosely. Third, move the TS head by 0.0023". On my new TS, lateral adjustment can be made without unlocking the base from the ways. My finger is pointing to the lateral adjustment on this TS. If you have a traditional TS, making this adjustment may take a little trial and error. Once the adjustment is made, tighten everything backup. In my case, after tightening the chuck, I loosened the TS base slightly and re-applied sufficient dead center pressure. This TS does not lose center when the base is loosened and re-tightened.

BS7.JPG BS9.JPG BS8.JPG

And finally, take another pass and re-measure the shaft diameter at left, center and right.

In this particular case, the shaft came out measuring 1.3197" 1.3198 and 1.3199; thus, it is holding +/- 0.0001" -Good enough for this piece because it will be cut to rough form and about 10 thou oversize on the lathe, six fins will be cut on the mill, it will be heat treated then, finished to size on the tool cutter/grinder.

Here's the rough blank. In this position, the taper will be cut next and I know there will be enough clearance to do the work because the logistics were checked up-front. BTW, this metal is a joy to work on. This was spun at about 850 RPM and 0.004 IPR (left to right cut) with naked carbide TCMT 3251 insert. The insert I used was borderline shot but, the piece has a beautiful finish. It's practically hard to screw-up good quality metal.

BS5.JPG

We'll continue later... Please be patient because I gimped-up a few fingers and am on light duty these days...

Ray

BS7.JPG BS8.JPG BS9.JPG BS5.JPG BS1.JPG BS2.JPG BS3.JPG BS4.JPG
 
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Ray C

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#2
OK, time to cut the taper -which is very easy. First some easy math. The one side angle (for a Brown&Sharpe grinder arbor) needs to be 7.125[SUP]o[/SUP] and an angle is expressed as the Tangent of the Rise divided by the Run. We need to make two measurements from the compound. One measures the Rise (deflection of the compound) and the other measures the Run (distance traveled). You need to setup two travel indicators as shown. The bottom one measures the distance traveled and the top one (which is fixed to the tailstock) measures the run of deflection on the compound.

BS10.JPG

I'm going to use a travel distance of 1/2". First, set the compound manually to the angle of 7.125[SUP]o[/SUP] as best as you can. Second, set the bottom indicator so the plunger is depressed a good 1/2" and zero the scale. With the top one placed against the compound, move the compound until the bottom indicator shows 1/2" of travel. Now read the top indicator. 0.5 x Tan(7.125) is 0.0625. That is the number we're looking for on the top indicator. Keep resetting the carriage, adjust the compound and rezero the indicators until you get a measurement on the top indicator of 0.0625. When you get it, lock the compound down.

If you're looking to cut an MT2, the one side angle you need is 1.4307[SUP]o[/SUP] so, following the procedure above (with a 1/2" travel) you need to read a deflection of 0.01249. For MT3, the angle is 1.4377[SUP]o[/SUP] so, it's 0.01255.

When you make the cut, you will not move the carriage at all once it's been roughly positioned... you will turn the compound crank to make the tapered cut. First, you need to extend the compound all the way out. Get the bit close to the metal by positioning the carriage and crossfeed then, lock the carriage. Next, check for clearances (no banging tools now), turn on the lathe, make bit contact by moving the crossfeed in and crank backward on the little compound dial. It will shave off a ribbon and start to form the taper.

Please note, I've decided to cut the taper small end at the left. I could reverse that if I wanted to (by rotating the compound the other way, running the lathe in reverse and cutting on the far side. For this piece, it's not possible because the tailstock is in the way. If it were a short, unsupported piece like an MT2 stub, I would do exactly that.

BS11.JPG

Here's a closer view and some progressions along the way. Normally, I don't like to run so close to the chuck but, theres is no powerfeed going on here and I'm working from left to right.

BS12.JPG BS13.JPG

So, here it is all done and I've cut a 1" shaft on the end. I'll mill a square on the end to drive it with a wrench. The area between the black lines is what I need to ream the grinder hubs. I'll leave the excess material in place. Later on, we'll toss this piece in the mill and make the cutting fins.

BTW, this is the color of good carbide cut swarf -beautiful blue indigo. Sadly, because of the angle of the cut, I could not utilize the chip breaker and that swarf is razor blade sharp. The blue glove does not provide protection; it's only there to keep my hand clean.

BS14.JPG BS16.JPG

Ray

BS10.JPG BS11.JPG BS12.JPG BS13.JPG BS14.JPG BS15.JPG BS16.JPG BS17.JPG
 

Ray C

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#3
Here's a little more demo of how to cut a Morse stump. First, use the angle setting procedure described earlier. If you can run your lathe in reverse, set it up this way:

M2.JPG

If you have a forward-only lathe, set it up this way:

M1.JPG

Note the differences in how the compound angle points for each case. BTW, I just made that MT2 stump in about 5 minutes....


Ray

M2.JPG M1.JPG
 

george wilson

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#4
I would definitely mill. A formed wheel will not keep its form very long. Probably just good for cleaning the milling scallops out of the cuts,if you get my meaning.
 

Ray C

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#5
Definitely on the mill 60[SUP]o[/SUP] apart. I'm behind on this project. That one nasty looking finger had a blood clot and needed some special attention the other day so, I'm taking it easy these days.


Ray


I would definitely mill. A formed wheel will not keep its form very long. Probably just good for cleaning the milling scallops out of the cuts,if you get my meaning.
 

Ray C

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#6
Hi... After a little pause, I decided to spend a little time on this today. The facets are basically cut and if the fingers are up for it, I'll clean them up just a little more and heat treat this part. After that, we toss it in the tool grinder and make it sharp.

Very simple procedures here to cut 6 flutes. I made passes with a side cutter, a dovetail cutter and a normal endmill. 6 flutes, 60[SUP]o[/SUP] apart. Very self explanatory except the first photo where I was running the table back/forth to find the counter-angle of the taper.

C1.JPG C2.JPG C4.JPG C5.JPG C6.JPG

Ray

C1.JPG C2.JPG C4.JPG C5.JPG C6.JPG
 

awander

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#7
Hi ray:

I'm curious as to why you made it a left-hand cutter(if there was a reason). I know it will work in either direction.....
 

Ray C

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#8
When I used some store bought (right-hand) cutters and used them in the lathe, the wrench slipped off and the knuckles went crashing into the lathe's splash guard. Pulling toward me, I'm less likely to end-up with more dents in the splash guard.

BTW, the reaming is not a delicate process and it takes some good elbow grease to cut the metal... So yes, they are left hand by design.


Ray


Hi ray:

I'm curious as to why you made it a left-hand cutter(if there was a reason). I know it will work in either direction.....
 

awander

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#9
When I used some store bought (right-hand) cutters and used them in the lathe, the wrench slipped off and the knuckles went crashing into the lathe's splash guard. Pulling toward me, I'm less likely to end-up with more dents in the splash guard.

BTW, the reaming is not a delicate process and it takes some good elbow grease to cut the metal... So yes, they are left hand by design.


Ray
Makes sense; thanks!
 

Ray C

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#10
Woops, I forgot to mill a square on the shank to drive it... Fixed!

C7.JPG

C7.JPG
 

Ray C

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#11
Oh well... Win some, lose some!

Here it is heat treated to RC62 and sand blasted... -and look what the sandblasting uncovered... a fracture. This is what I get for not following the procedure. In this case, I did not normalize the metal before machining it. Everything else was done by the book. Most likely, it had a bunch of internal stress that busted loose somewhere along the line.

The part was slowly brought-up to 1500, held for 10 minutes, oil quenched down to 150 degrees then tempered at 350 for 1 hour. The new piece is now in the furnace getting normalized... I get to do this project over. The crack is so deep, I won't even risk practicing on it in the tool grinder.

Live and learn.

(BTW: It actually tested at 62 RC so that's encouraging).

Heat cracked.JPG

Ray

Heat cracked.JPG
 

Ray C

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#12
This time, I fully normalized the piece at 1600F, 1hr soak and open-oven cool. When turning this, it felt and looked like a totally different metal. The stock I had for this came with certs but didn't specify the condition. It looked to be TGP but no heat condition was specified. Anyhow, I couldn't believe how nicely this machined. ...Wish I could use nice stuff like this all the time...

Take 2.JPG

Ray

PS: As you can see, Frankenfinger is doing incrementally better. Stitches will remain for 2 more weeks and it might need a little more work. LOL, this is probably the only time you'll ever see me with a clean hand...

Take 2.JPG
 

Ray C

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#13
Can you say HOT!

HOT.JPG

Fresh out of the oil bath and first temper. Tempered at 325 for 1 hour. It's still hot.

Remake1.JPG

Second temper and cleaned up. You don't do the second temper until it's dropped to room temperature after the first temper. Second temper must take place within 24 hours of the first. Sooner is better.

Remake2.JPG


I'll check the Rockwell tomorrow. Metal likes to wait a day before it reveals it's beauty...

BTW: No cracks this time. Normalizing helped and I also preheated the oil to 200F.


Ray

HOT.JPG Remake1.JPG Remake2.JPG
 

george wilson

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#14
Ray,did you get a truly hardened reamer quenching in 200 degree oil? What you really need to do is get a proper reamer fluting cutter. It leaves rounded gullets in reamers. Having those sharp gullets is an invitation to crack. Even number or letter stamped impressions can lead to cracking. That's why some marks are made with a series of little dots(ugly as they are).

I make lots of stamps. I never quench the whole length of the stamp's shank. If I do,using W1,it invariably causes the stamp to crack right up the middle. So,I just heat up about 3/4" of a 2 1/2" long stamp. W1 is really treacherous stuff.(I realize you were using 01,of course.)
 

Ray C

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#15
George,

I'll check the Rockwell later tonight.

Yes, I've since read exactly what you are talking about. The books all say that large dimensional changes or machining with sharp angle is a setup for a crack. It is apparently most common during the quench and the suggestion was to raise the oil temperature. Some books say as high as 400 which seems way too high. Other books said 200 and I tried that and at least this one did not crack -so I'm happy about that. I used a large volume of oil so it would soak-up the heat without raising the temperature too much. The oil was 220 degrees when I pulled the part out. From there, I let it cool to 150 then tempered it.

Oh, yes, this is O1 tool steel. I have heard that W metals are very hard to control cracking so I stayed away from it. I only need this tool for hand operation and I made it slightly bigger than needed so I can resharpen if necessary. I hope it will do what I want it to...

Ray




Ray,did you get a truly hardened reamer quenching in 200 degree oil? What you really need to do is get a proper reamer fluting cutter. It leaves rounded gullets in reamers. Having those sharp gullets is an invitation to crack. Even number or letter stamped impressions can lead to cracking. That's why some marks are made with a series of little dots(ugly as they are).

I make lots of stamps. I never quench the whole length of the stamp's shank. If I do,using W1,it invariably causes the stamp to crack right up the middle. So,I just heat up about 3/4" of a 2 1/2" long stamp. W1 is really treacherous stuff.(I realize you were using 01,of course.)
 

Ray C

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#16
It's a hard piece to test but, I got three readings of 59, 60 and 59 at the square end of the shank. I'm guessing (hoping) the cutting edges are a little harder because they would have cooled much faster. The book says 65 is the top-end for O1 and for all practical purposes, 62-63 is what most folks commonly shoot for.

We'll find out how well it works soon enough...

Ray
 

valleyboy101

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#17
Thanks Ray,
I really enjoyed your posts and learned a few things from your excellent explanation of the setups.
Michael
 

Ray C

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#18
This is bugging the crap out of me... I have two books on heat treating; one costing over $300 and another over $100. These are professional series reference books... So why the heck do I find discrepancies with stated oil preheat temperatures all over the place?

I've decided I really like machining tool steel and want to do more -but it might as well be made of A36 if you can't heat treat it right...

It's only the tool steels where the discrepancies arise... I have a book dedicated to tool steel and even it is different from the other two.


Ray
 

Ray C

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#19
LOL: Because all I had to work with was O-1. Also, the oven is wired with nichrome right now and 1800 degrees is pretty close to it's top end. I have some Kanthal on hand but don't feel like changing-out the coil unless I have to.

BTW, there's really not that much hassle in oil or brine quenching. Matter of fact, it adds to the fun factor. I just wish the books had more consistent recipes.


Ray


O-1 has a complex heat treating process involving, like you stated, oil quenching and so forth.

I'm wondering why you didn't choose A-2 tool steel as the heat treatment for this material is straightforward? A simple oven preheat then a run up to 1800 followed by an air cool down to 150 or so.

The differences in the heat treatment is probably why A-2 is specified for reamers rather than O-1.
 

george wilson

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#20
I make all the punches and dies for our jewelry business from A2,because I want them to last as long as possible. But,you have to carefully wrap A2 in hi temp stainless wrap and seal it well. Also,I'll put a small bit of brown paper in the heat treat envelope to burn out any oxygen in it. Too much paper will burst it right open,and cause the surface of the A2 to decarb and ruin it. I tear open the stainless envelopes with tongs and scissors and hold the part up to a stream of air ASAP. It will harden in still air,but I lie to lower the surface temp as soon as safely possible to avoid de crabbing when exposed to air.

I have found A2 to be much safer than 01 about warping or cracking. The slower the quench needed,the less shock the steel is exposed to. Air hardening steels are the safest in that respect. And,they last longer as tools,too.
 

Ray C

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#21
Quick update... I cut facets in the reamer and it worked-out well. Since it's my first real utilization of the tool cutter/grinder, I'm going to skip those details -of the mindset that I do not wish to outline practices that I made-up on the fly. Suffice it to say, I used TDIs and just about everything else in the shop to set the angle properly and it seems to have worked. Basically, I eye-balled the amount of backside relief.

In order to test the angle, I whipped-out an aluminum hub with a rough internal taper done in the lathe then, reamed it by hand. The swarf packed up nicely in the cutting grooves and there was no backside rubbing. -And best of all, the hub fit on the spindle like a glove on the first shot. I feared I would end-up in the situation of getting it close then, nudging the angle, recutting the reamer and trying again. -I got lucky.

F2.JPG F1.JPG

Ray

F1.JPG F2.JPG
 

awander

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#22
Doesn't it feel good when you figure something out, implement it, and then it just works?

How's the hand healing?
 

Ray C

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#23
Yes, this was a nice surprise and those are always welcome. It was also nice to spend a few hours in the shop which I've vastly reduced to let the fingers get back on track. Two fingers are doing very well. Some numbness on them to varying degrees and the cut area is not toughened-up and is fragile but, basically doing well. The third finger still has the stitches and the pad part is basically a dead hunk of beef jerky. The dogs keep eyeing it... That one will be a slow heal. -Thanks for asking...


Ray

Doesn't it feel good when you figure something out, implement it, and then it just works?

How's the hand healing?
 

blay127

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#25
i know this thread is old, but i just wanted to say thanks for taking the time to show the different setups for turning tapers. I will be doing some MT3 tapers in the near future and this has helped a ton. thanks!
 
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