360* Rotating Back Blade Project

[GuglioLS]

I had a few minutes to burn before my tee time and decided to set up the bottom plate for the pocket milling on it. I positioned it so that I would have enough travel in all directions and then indicated it in square and found center. Here is a video of how to indicate and find center on a large piece.



After indicating it square and parallel to the table axis, use your indicator and pick up the high point at each edge. Use the quill to lower the indicator and move it from side to side and you will see where the high point is as the needle goes to a spot in one direction and then reverses. That spot is the high point so move the dial to zero. Then swing over to the other side and see what that reads. Then split the difference and move the dial again to zero and check both sides until they read the same. Then you are on the dead middle of the piece in that direction. Set your DRO to zero. Then do it for the other direction too and you will be on center. Round pieces are easy as you can sweep around the diameter.

You can also use a depth mic and measure to a pin in the quill and do the same thing. I like using the test indicator for better accuracy.

Here's the first part of the pocket I am milling where the box will sit in and be "trapped" by the steel plate.



Pocket milling has to be exact because if you miss a dimension, you could cut a groove to the outside. So you have to pay attention on this type of machining. You also need to measure frequently because of cutter flex. Your finish pass should be the same depth of cut as the last pass used to measure. This assures you the end mill will cut the same amount off as you have measured. Otherwise it might vary and you'll cut more or less than anticipated.



Rob-

 

[GuglioLS]

Here you can see I had to mill the ends square. I set my 1-2-3 blocks up with a test indicator in a surface gage right on the mill table to check while machining.



Rob-

 

[GuglioLS]

Oooh wee,
I got lucky ... the side plates fit the pockets perfectly and the pocket is the right size. I gage blocked the box dimensions and did the same for the pocket dimensions.

In milling the pockets, I not only had to fit the width of each plate respectively, but just as important, hold the outside and inside dimensions when the sides are bolted together. I ended up clearing the inside pocket by.001" per side but held the outside dimension right on the number. That will keep the box from flexing outwards 100% and the screws now only hold it together in the middle.

Here is a picture of the plates sitting in their pockets. Ends are .750" thick and sides are 1.000" thick.



I have lots more to do to this plate. Drill and counter bore for all the SHCS (socket head cap screws) and bores for the worm gear. I still have to establish the bottom of the pocket too, you might have seen the red Dykem on the bottom? When pocket milling, except when roughing, you don't want to cut the sides and the bottom at the same time or the cutter may suck down and there goes your depth. So I rough the pocket out near depth, lower the table so my cutter is off the bottom by about .020' and then start cutting the sides. Then I go back and cut the bottom finished and stay away .001" from the sides. Lots of steps to take and stuff to remember if you want your work to turn out good.

I also have to radius the end plates to match the radius of the pocket. All this was a huge step because I now have numbers to reference to when I do the top plate. I say reference, because I will still individually check each size to be certain it fits and works rather than take it for granted.
Rob-

 

[GuglioLS]

After seeing what Rob's been up to, I figured, I too better get with the program. Today I hooked up the Back Blade to my tractor for the very first time. I painted the drive coupler and attached it with the 1/2" shear bolt. Then I made up the hoses with quick connects that will attach to the hydraulic motor to drive the worm. The control valve is all hooked up and ready to go.

In addition to the 90* worm Gear Drive that Rob is so painstakingly machining for me, I want to use a hydraulic cylinder to adjust the swing offset. I have this cylinder lying around so I set it in place to see if it will work.



Here I am holding the Hydraulic lines and analyzing the situation.



I’ll have to wait till the mounting bracket for the gear box is installed before I can mount the swing offset cylinder. It will be an integral part of the gear box mount.

Larry

 

[GuglioLS]

Hahaha, don't hurt yourself Larry. Looks like real back breaking work there. ;D ;D ;D But your blade sure looks nice. I was just picturing the gear box and hydraulic cylinder on top of that spline shaft. It is going to look really cool for sure.

While Larry is slaving away in New Mexico, his Californian big brother has been busy too. As I said earlier, the pocket milling is strenuous and nerve racking since a mistake or a misread would send a steel wall out of bounds. The top plate should go a little faster with experience I gained from doing this one.
The mill cuts came out really nice and clean.



With that out of the way, the rest of the machining was drilling and counter boring for the SHCS. I sure hope they all line up? ???
I'll still have to flip the plate over for the counter bores on the other side though....and I still have to chamfer all the holes. They are still sharp edged now. That one hole in the corner inside the box will be Larry's drain hole. I will put a giant lead in on that one and tap the other side 1/4"NPT.



I also rough drilled out the hole for the Ø2" hollow spline shaft.
I say rough drilled because I will bore it to size to be sure it is on location. Many times a big drill like this will walk off several thousands so boring it after will put it back on location.
Here is Wesley showing the size of this drill.



Today is his birthday. He turned 11. Loretta and I took him to Sportsmart after his Karate lesson to get him a gym bag to punch and kick the **** out of. He wanted one for practice training.

So that's all I got done today.
Tomorrow after golf, (if I feel like it ), I'll bore that hole and finish up the bottom plate. Then start on the top plate. After they are both to the same state, they will go in the rotary table to open up the counter bores for the collars and oil seals.



BTW, did you notice I was able to mill and drill every single hole without taking my set-up down or moving any clamps? Also managed to miss drilling the parallels that hold the plate above the table. I hope Larry figures out that hose routing soon.

Rob-

 

[GuglioLS]

I talked to the boss (Larry) today and he told me to get it in gear.
He told me he wanted it by April and I said "You mean this year?" LOL ... So I better get on with it. Really, Larry has been very (overly) thankful and shown his appreciation very much.

Tonight I got the hole bored out for where the hollow spline shaft will stick through the bottom plate. I'm taking it to Ø2.008" at 550rpm using the boring feed on the milling machine. The feed indicator has 1-½, 3 and 6 for feed rate and is tied in with the RPM. I never did know what that meant. The 1-½ is the slowest and 6 the fastest feed. For holes around this size I usually rough at 6 taking .030" per side and finish at 3 taking .010" per side. Otherwise the cutter on the boring bar wears out. I guess large diameter holes would need the 1-½ rate? Who cares...

Here are some boring pictures.
Start boring...



Halfway through...



And near the bottom...



Side Note:
When boring I also always use cutting oil or STAT oil which is a compound oil that seems to work better for real high speed, high rpm cutting. We used to use it on the Deckel GK21 Pantograph machines when running about 20,000 rpm with little tiny cutters. With the advent of CNC's, I don't know anybody that knows how to run them anymore. (Or even what they are?) I used regular dark cutting oil on these holes.

Rob-

 

[GuglioLS]

Here is the bottom plate all finished except the counter bores that will hold the thrust bearings, collars and oil seals. Oh, and will also machine a big radius on every corner yet, so Larry doesn't bust his shins on it.



I have also set up and roughed what I can on the top plate. I am using the numbers from the bottom plate as a guide to get me close to the finished dimensions. I roughed these out with a 4 flute solid carbide endmill but will finish with a 2 flute hi speed endmill for better finish. I will be taking less of a pass and the chips clear better/faster with the 2 flute.





Unfortunately, the top plate is shorter than the bottom plate so I can't mill the entire pocket in one set-up. I've set the plate up so I can mill the long pockets and part of the ends and I can still drill all the holes. But I will have to reset the plate 90° and pick up centers again to finish the end slots. Not only that, but I'll have to do that 2 times because the end slots are too far apart for the "y" travel on my mill to do both in the same set-up.. Bummer.

Getting pretty close to seeing the light at the end of the tunnel ... and it ain't a train!
Rob-

 

[GuglioLS]

I am completely dumbfounded with the amount of work Rob has accomplished in such a short period of time. I think I got a pretty good deal for 9 minuets of my time to “repair” Rob’s tractor wouldn’t you say?

So now were up to date on this project – So what do you think so far?


Larry

 

[3RRL]

WOW Larry,
What a documentation you have started! I can't wait to see How it ends up. Sure hope it works just as you planned. I'll be the first to say you definitely got your 9 minutes worth! Of course you forgot to mention you spent all weekend re-wiring my tractor and installed a complete new automotive fuse box in it and fixed a whole bunch of troublesome electrical connections on top of that. You are too gracious to even mention that.
This is a fun project.

 

[GuglioLS]

WOW Larry,
What a documentation you have started! I can't wait to see How it ends up. Sure hope it works just as you planned.

Yea me too, I'm counting on you to make that happen for me! Not that it matters or anything - It took me nearly 8 hours to compile all your documentaion into Word so that I could post it. I've got 22 pages of text, pictures and HTML code

I'll be the first to say you definitely got your 9 minutes worth! Of course you forgot to mention you spent all weekend re-wiring my tractor and installed a complete new automotive fuse box in it and fixed a whole bunch of troublesome electrical connections on top of that. You are too gracious to even mention that.
This is a fun project.

Thanks for the generous compliments The way you make your machining look easy for you is what electronics and wiring is for me. I'm sure glad this is a fun project for you. I was getting a little worried there.

I guess I bored everyone ? no replies yet

Larry