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Mystery Project...

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Ray C

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Quick update... The new drive mechanism is sweet! Haven't made a proper handle for the drive rod but there's a couple extra inches of threaded rod on the end so I clamped a 6" vise grip pliers to it and with just turning force from a fingertip, it drilled a half inch hole in a piece of scrap -effortlessly. The action is very smooth. I'll put a few finishing touches on it and update later tonight. Hopefully this weekend I'll have time to set the final alignment on the disk. At some point I might buy some ACME rod and re-make the half nuts -maybe, maybe not... Right now, it's 5/8 coarse pitch threaded rod left over from a project last year and I'll keep my tradition of being a shop-drop machinist...


Ray
 

Ray C

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Oh boy, happy camper here... Instead of putting on some finishing touches, I started playing around with alignment and doing some tests. I did a half decent job of aligning one station and mounted a known good rod in the collet and checked with a DTI. It was looking good on side and top. I also tested the side-to-side offset movement and when an adjustment was done there, it didn't introduce any angle offset. So, time for the big test... Mounted a piece of scrap, faced it, touched it with a center bit and followed-up with the first bit at hand (which was a 19/64").

Came-out just about spot-on. Bore diameter came out to 0.298 and concentricity at the edge (measured in many places) and according to this caliper, came out to 0.247 and 0.2475 all the way around.

Test 1.JPGTest 2.JPG

-So far, so good...

Ray

Test 1.JPG Test 2.JPG
 

Ray C

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OK, a little more fiddling around with this today -not much.

Here's an MT3 test shaft to get the taper blocks aligned. The shaft is made of 1117 (not my favorite stuff) because it machines easily. It took a little while to set the taper angle but it came out nicely and fit fine. The shaft is 1.125" diameter and a little over 3" long. I was shooting for dead on accuracy since it will be used for alignment purposes. It came out nicely and measures 1.1250 at about +/- 0.00015 (reading between the lines of the DTI). -Good enough. The only way to get it better is with a TPG and gummy, unhardened metal doesn't grind well with the wheels I have. FWIW, the shaft was spun at 900 RPM, final DoC was 25 thou and feedrate was 0.005 IPR, TNMG 321 insert. Nice satin finish. With low carbon sulfur metal, you don't seem to get that nice chrome look that I like so much...

MT Shaft 1.JPGMT Shaft 2.JPG


Right now, the base of the TS is flat -about dead-on. Here's a general setup to check for any unwanted angle in the up/down direction using the MT test shaft. ... And yes, since I'm looking for real deflection measurements, I kept the DTI nice and flat wrt the cylinder. I only checked one taper block and it was angled upward and the DTI deflected 1.5 thou over the 3" shaft. I calculated the angle then, removed the block, put it in the surface grinder with an appropriate shim (which turned out to be 0.002") under one end and adjusted the seating surface angle of the block. The adjustment corrected the problem and the DTI was reading well within a half thou over the 3". If I removed and reseated the taper/cylinder, it was in the same spec but sometimes with the angle going the other way. This is probably due to the slight roughness of the tapered part and it's not seating repeatably. -Basically, it's neutral and I'm calling this one done. I've got a couple more to do. I only takes a few minutes to check and adjust. While I was at it, I checked the outer surfaces of the taper blocks and they're running very true to about 1 thou over their 6" length. -That not of great importance though as I don't plan to measure or setup off those surfaces. When I made the blocks though, I was trying different grinding wheels and also practicing making blocks really square (which isn't really all that easy).

MT Turret Align.JPG

Next up: The rotating disk has provisions for registraton/index pins to set the location when changing from one station to the next. Soon, I'll have to sink the holes in the top supporting plate. I don't have experience with dropping precise holes so, I'll have to noodle on that...

Ray

MT Shaft 1.JPG MT Shaft 2.JPG MT Turret Align.JPG
 

eightball

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great work ray, havent been on line much due to the other things im dealing with love your work
 

Ray C

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great work ray, havent been on line much due to the other things im dealing with love your work
Thanks, eightball... I appreciate the words of encouragement. So, how are you doing?

As far as this project, I've had some ups&downs and considered scrapping it more than once due to the hassle of working on it while using the machine for other work. It is turning-out nicely and I'm somewhat pleased that the overall alignmnent of the assembled components is pretty good and only needs some tweaking of the individual blocks. I was also disappointed that the gear mechanism wasn't to my liking. I really didn't want a hand crank the size of a steering wheel on the side of the machine. Turns out though, the screw drive is a thousand times smoother, easier to operate -and totally unobtrusive.

We're right around the corner of finishing it off... but, I only put an hour or two every couple days on it except weekends.

Ray
 

eightball

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i thought you would use the same rack as your carriage uses. As far as my self im just tired of going to treatments everyday. id rather be working . Ive only had one really bad day so far but i have 3 more weeks of radiation to go. thanks for asking btw beautiful work!
 

george wilson

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Ray: You can just index your blank tool holding sections and use a drill and reamer in the headstock to drill accurate on center holes on your turret to insert your tooling in.

I have a small turret attachment that fits into a #2 MT. tailstock. It has 6 positions that are easily indexed into place. The instructions were to bore out every hole with the lathe's headstock before using the holes to hold tooling. I did that,and mounted a center drill,a drill chuck,and a few more tools in it which I used to use to make a little product to sell.

You could hold the whole tailstock turret in the palm of your hand.
 

Ray C

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Yes indeed thanks -and for the next blocks I make, that's what I'll do! I jumped the gun when making a few toolholders first... No big deal for the ones I already made, the setup time is just a few moments. Hopefully later today, I'll drill the indexing holes so the disk positions repeatably from station to station. Wanted to do it yesterday but, I just ran out of gas...

I'd love to see that tiny one you made...


Ray

Ray: You can just index your blank tool holding sections and use a drill and reamer in the headstock to drill accurate on center holes on your turret to insert your tooling in.

I have a small turret attachment that fits into a #2 MT. tailstock. It has 6 positions that are easily indexed into place. The instructions were to bore out every hole with the lathe's headstock before using the holes to hold tooling. I did that,and mounted a center drill,a drill chuck,and a few more tools in it which I used to use to make a little product to sell.

You could hold the whole tailstock turret in the palm of your hand.
 

Ray C

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Well, the old tailstock is off and I've been using the new one since Friday. It works great and I like it much better even though there are only two blocks on it. I have a couple more already made -one is for a 5C holder and another is a shorter one that doesn't have a taper yet.

Normally, I don't use a leader rest with a jawed chuck but, I wasn't shooting for accuracy here since it's only the handle for a T-bar but it still came out within 1.5 thou end-to end. Leaders are under-rated and I use them often on the propeller shafts. Some folks put a roller bearing on them but I just use the bronze pads.

You'll notice a slight cut-back on the shaft near the chuck about 1" long. When you use a leader and are making a second pass (as in this picture), you need to make a cut back on shaft so the leader pads don't hit hard on the raised part of the uncut shaft. -Keep that in mind. Things would probably get ugly if you bang into that. You need to watch your chuck clearance too so, always make a dig mark where you need to stop the cut before crashing.

Tbar Leader Support.JPG

And here it is... There are two positioning/indexing pins. Right now these pins are made of junk steel but I'll make some hard ones soon. -Good enough for now. You can see the top-side one next to the block. There's also one in the center that feeds-in from the underside. I'll spring load it for convenience. The operation is pretty fast. Loosen the plate, pull the pins, rotate to the next station, insert the pins (they came out very well aligned), tighten the t-bar and go. The individual blocks now have their internal alignment pin and the bolts are torqued to 17 ftlb (about the recommended torque for grade 8, 5/16" bolts). It only took a few moments to align the the individual blocks. It re-seats very well and alignment is staying at about a half thou.

I need to make some knobs for the t-bar. I'd also like to get 1:8 LH leadscrew instead of the threaded rod but that's not a real big issue and I might never get around to it... The black oxide on the plate needs to be re-done. I had oil on my fingers the 1st time I did it and it's smudgy. The base needs to be treated but, I kinda like the bare steel t-bar and nut.

Anyhow, I like using it... Now I need to buy an extra chuck for a dedicated center bit.

Tbar.JPG

Ray

Tbar Leader Support.JPG Tbar.JPG
 

Ray C

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I did this the other day but forgot to post it...

If you look at post #124, a special alignment tool was made that is MT3 on the end and just a cylinder with 1.25" diameter on the other end. The other day, I grabbed a piece of drops and turned down a little section to 1.25". Here's the alignment piece lined-up with the piece in the chuck. It lines-up perfectly and will do so no matter what station is used on the turret or if you re-position the same station. This had a happy ending.

It was incredibly hot/humid today and I just cleaned-up the shop a little but, did find time to make some knobs for the various handles on the turret. I'll post pictures later.

BTW: The piece in the chuck is hot rolled 1045 and the alignment tool (on the right) is 1117. They were cut in exactly the same conditions of 900 RPM, 0.005 IPR, carbide insert (probably the same one) and a final pass DoC probably of 20-25 thou. Big difference in finish and if anything, this points out the difference between medium carbon and low carbon sulfur metal. The 1045 looks like a mirror chrome finish -very smooth. The 1117 is satin -also very smooth to the touch. This is why it's fun to experiment with different metals. My go-to metals are 1045 and 4140. Very easy to work with and they cut the same. I'm bringing this up because a couple people have contacted offline and asked how I get nice mirror finishes while they could not get the same results using the speeds/feeds that I posted. Assuming the the bit is setup properly, it takes medium or high carbon steel to get that finish. Sometimes, you'll cut into a random piece of hot-rolled and get a chrome finish on the first cut but, it goes satin after that. That's due to the external hardness condition of that particular piece. Generally speaking, once you get past the hard skin, you can't get a chrome finish on A36 or other low carbon steels. Also, once you get down below 3/4" diameter, most machines can't spin fast enough to keep the carbide happy.


line-up.JPG

Ray

line-up.JPG
 
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I'm still here Ray, nice work so far. Got a ways to go yet huh.

"Billy G"
 

Ray C

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Hi Bill...

I haven't been putting too much time on this the last few days. It's basically done but needs some finish work like knocking off the edges, and surface finish stuff. It's already part of the shop.

Thanks for checking in... Glad you're here keeping an eye on me...


Ray


I'm still here Ray, nice work so far. Got a ways to go yet huh.

"Billy G"
 
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