Milling keyways in a long shaft?

[cwoll]

I have a 8ft long 2inch shaft to machine some keyways in all along the shaft. The keyways need to be aligned. What is the best way to make sure the keyways stay aligned when moving the shaft in the vice?

Thanks
Clarence

[Gunney]

An easy and fairly accurate way is to set the shaft up for milling using v-block clamps at either end of the table. Mill the ones you can reach. Remove the v-block that will be moved off the table, but leave the other one clamped to the shaft, moving it to the other end of the table, and place the removed one back at the other end. Mill the ones you can now reach and repeat the procedure. As long as your v-blocks are a matched pair, and at least one of them is always clamped securely to the shaft when it is repositioned, it is a simple job.

Patrick

(01-17-2014, 01:18 AM)cwoll Wrote: I have a 8ft long 2inch shaft to machine some keyways in all along the shaft. The keyways need to be aligned. What is the best way to make sure the keyways stay aligned when moving the shaft in the vice?

Thanks
Clarence

[Gunney]

I should add, though it should be obvious, that the vise can be used (assuming it is trammed well) between the v-blocks to easily align the shaft parallel to the table travel.

[big job]

Common procedure here with long marine shafting. We simply use
a pipe vise. We have machined various jaws. We have two large
"Reed Vises" our tables are 10x52 and fits tee slots perfectly. We
index the vise, call it a tail stock vise. With some blue'en
and some scribe marks and two fixed pointers, thats about it. So
save that ole pipe vise. Then an emergency home owner comes in
to tread a 1inch pipe thread, no problem to thread on the mill
table (we have dies) and you aint going to tip over a 3,000lb
mill. Just one more hold down fixture for the draw.. Not being a
fanatic, but we even put a Cincinnati decal on these two.

[cwoll]

So your saying clamp the vblock holding the shaft with the vices. I will try that. I'm concerned that the clamped vblocks holding the shaft is not as good a hold as clamping the shaft directly with the vices. I'm just going to have to set it up and see how it feels.

Clarence

(01-17-2014, 02:11 AM)Gunney Wrote: An easy and fairly accurate way is to set the shaft up for milling using v-block clamps at either end of the table. Mill the ones you can reach. Remove the v-block that will be moved off the table, but leave the other one clamped to the shaft, moving it to the other end of the table, and place the removed one back at the other end. Mill the ones you can now reach and repeat the procedure. As long as your v-blocks are a matched pair, and at least one of them is always clamped securely to the shaft when it is repositioned, it is a simple job.

Patrick

(01-17-2014, 01:18 AM)cwoll Wrote: I have a 8ft long 2inch shaft to machine some keyways in all along the shaft. The keyways need to be aligned. What is the best way to make sure the keyways stay aligned when moving the shaft in the vice?

Thanks
Clarence

[PixMan]

You could also use the V-blocks together with the vise. Use the V-blocks to set the orientation and height in the vise, though you'd likely have to but spacer blocks under them to bring the workpiece up to the proper height in the vise. Start with both V-Blocks on one side of the vise, supporting the long end of the workpiece. Clamp the work into the V-blocks, not fastened to the table. Then clamp the vise to hold the work. Make your first cut.

Now remove the spacer from under the V-block that's closest to the vise, and move that V-block & spacer to the other side of the vise. Loosen the vise, slide the work over to the other V-block, clamp the vise and make another cut. Lather, rinse, repeat.

Easier to do it than to describe it.

[wrustle]

Way back when, I had some long 12 foot long shafts that had to have keyways milled on each end and in line with each other. They were only about 1.5" in dia. so they weren't ball busting to pick up, but I had 90 pcs to make so at the end of the day, you were feeling the pain!

They were shafts for a windmill farm that was being put in out in the Berkshires of Western Mass.

Anyways, at the time, all I had was my Lagun FT-2 knee mill with a 50" table??.....can't remember the length for sure, but it was way the hell shorter than 12 feet, I can tell ya that!

With my machine being so close to my office wall, I had to punch a hole through the drywall into my office for the shaft to go into in order for it to fit onto the machine. To support the end hanging out I simply placed a step ladder in my office with some blocks under the legs and had the bar resting on one of the steps positioned to just the right height.

Yes sir.....Yankee ingenuity at it's finest right there!

Well, to make all this work, I clamped the bar right to my table using the middle t-slot to locate the shaft.

Then I milled the slot at the far end of the table, clamped a v-block upside down just off the table at the opposite end and ran an indicator over the top tapping it in to zero across the top. Released the shaft, moved it down the full length of the table and indicated my v-block for zero again, then added another at the opposite end and repeated the process until the end of the shaft was able to have the keyway milled at the opposite end.

It sounds really long and involved, but it was really a piece of cake.

What helped out a lot was using a precision level to line up the v-block each time to get in the ballpark before indicating and for the most part it was always within a few thousands before any rotating was required to bring in to zero. That was achieved by simply snugging up a c-clamp on the OD and just tapping it in the direction necessary to make the bottom of the v-block read zero.

The hardest part of the entire job was bringing the shaft outside every time to turn it around because I did not have enough room in my shop to swing it around. With 90pcs to do it wasn't long before those things felt like they weighed a ton each!!!


The v-block in combination with the vise sounds good as well, but sadly my v-blocks back then were too low for my vise, so this was the only thing I could think of to keep the slots in line with each other.


Best Regards,
Russ

Here's an old picture of my son Christian watching my Lagun mill a keyway in a long shaft. Certianly not as long as 8 or 12 feet, but once again, I find the best method is to clamp it in the middle t-slot to locate. Keeps the part aligned, and also allows you to mill nearly the length of the table without any lack of rigidity issues.

[cwoll]

I think I got a plan. I will got some import vblocks from MSC and I will set one up in the center where it is not in the way. I can then with my dial indicator dial it in after repositioning it.

The only problem I have now is the Vblock clamp does not fit the shaft. I will have to make a new clamp before I can precede with this project.

Clarence

   

[TomG]

(01-17-2014, 06:10 PM)cwoll Wrote: I think I got a plan. I will got some import vblocks from MSC and I will set one up in the center where it is not in the way. I can then with my dial indicator dial it in after repositioning it.

The only problem I have now is the Vblock clamp does not fit the shaft. I will have to make a new clamp before I can precede with this project.

Clarence

Clarence,

It would take much effort to drill and tap the side of a couple of pins to go in the block and then use threaded rod and a strap to clamp on the bar. A wide strap and a couple of pins and studs on each side would solidly lock it down.

Tom

[Sunset Machine]

I've used just a plain u-bolt muffler clamp to index from.