Milling a chamfer on a 1.5"x1.5"x8"

[sovcams_back]

Hello,
I have a 1.5"x1.5"x8" aluminum bar that I need to apply a deep chamfer to on a long edge using a manual Taig mill. That's close to the X-travel capacity of my Taig.
My question is: How do I hold this bar on the table with the long edge up so I can use an end mill for milling the chamfer?

What I don't have at this point: chamfering cutters, sine plate(s), sine vises.
What I have: a 2.5" screw-less vise, end mills, couple V-blocks, couple 1-2-3 blocks.

Do I need to mill any custom work holders first? What king of? Please advise.

 

[SmithDoor]

Hello,
I have a 1.5"x1.5"x8" aluminum bar that I need to apply a deep chamfer to on a long edge using a manual Taig mill. That's close to the X-travel capacity of my Taig.
My question is: How do I hold this bar on the table with the long edge up so I can use an end mill for milling the chamfer?

What I don't have at this point: chamfering cutters, sine plate(s), sine vises.
What I have: a 2.5" screw-less vise, end mills, couple V-blocks, couple 1-2-3 blocks.

Do I need to mill any custom work holders first? What king of? Please advise.

Welcome to the group.
You can buy milling cutters for that work.
I use a file for most of my work.

Dave

 

[Jasonb]

If you lay the square bar in your Vee blocks and clamp down on the top corner you can then mill your chamfer on the corner at the side of the bar, rough mock up obviously use both vee blocks and two clamps and setup along the X axis

 

[sovcams_back]

If you lay the square bar in your Vee blocks and clamp down on the top corner you can then mill your chamfer on the corner at the side of the bar, rough mock up obviously use both vee blocks and two clamps/ and setup along the X axis

Jason - thank you, how did I miss this simple idea? Perhaps I didn't consider it because my Vee blocks are quite large and I wouldn't have enough room for the deep chamfer at the side. However it's not too expensive to get two smaller Vee blocks which I'll do now following your great advice.

By the way, what would be another common work holding option for this job, NOT including chamfering cutters and tilting the mill head?
For instance, if I had a sine vise what is the rule of the maximum work extension beyound the vise jaws on both sides? My current vise is 2.5" wide, Would it be safe to hold an 8" long bar in it with a little over 2.5" overhang on each side or would I need to consider an additional support for the free hanging ends of this length?

Any other options? Can I expect to successfully machine a simple sine plate for mounting my bar for the chamfering job in question? I'm not sure about the right design though.

Just learning as you can see...

 

[djc]

...rough mock up obviously use both vee blocks and two clamps and setup along the X axis

Some things are given in the original post that would make this set up challenging. It is a Taig mill and 1 1/2" square stock. The bed is 90mm wide. How high off the bed would the top corner of the stock be assuming a minimal vee-block? What size of clamping step block would that height necessitate? What width would the clamping set up take? What length of cutter would be needed to reach the bottom of the stock and still clear the clamping set up? It would be difficult to move the clamps as you go as you'd also have to move the vee block below. Even if you were only putting a 0.5mm chamfer on it, that's a long cutter.

I would be tempted to make two French cleats out of plywood. Sit the stock with its bottom corner centred on and as deep into the centre T-slot as it will go. Use the cleats to stabilise it and set it to the correct angle. Drill holes in them and bolt into front and rear Tee-slots. Use hold down clamps at the ends (e.g. Low Profile Clamps). 8" stock plus a clamp either end should easily fit on the Taig bed, which is over 12" long. Cut the top of the stock using the X-axis as there is minimal clamping force in the Y-direction. Reinforce the clamping with a flat clamp over the top and two long studs in the front and rear Tee-slots. Move clamp as required. Use a wooden pad under it if clamping onto a pointy, unmachined part of the stock. A side benefit of this is that the stock is automatically aligned with the axis travel (not needed for this operation).

 

[sovcams_back]

Thanks djc! Sure Taig has lots of capacity limitations in all departments and I'm being a novice cannot clearly forsee all the upcoming problems.
I hope there are some other standard work holding techniques for the job in question.
Please HMEM'ers, give me some more options

 

[Ken I]

I leave the block square and use a large enough 90° countersink as a milling cutter - dead easy - especially with Aluminium.

Done it many times - but if yours is a bit large you can still do it in steps.

Alternatively clamp the square bar the way you have it between "V" blocks (you'll probably need 4) in a vice (vices if its long).

Regards, Ken

 

[timo_gross]

If you lay the square bar in your Vee blocks and clamp down on the top corner you can then mill your chamfer on the corner at the side of the bar, rough mock up obviously use both vee blocks and two clamps and setup along the X axis View attachment 140014

You can also mill the top were the clamp sits. and forget about the sides, if this is difficult to reach. You will just need to "jump the clamps" e.g. use three clamps and move one clamp out of the way at a time. Then you would be able to do very light cuts and still can use your too big VEE blocks.

 

[Jasonb]

If you have large Vee blocks then add a packer

A weldon shank holder or small ER collet chuck should allow for access but without knowing the size of your chamfer can't be sure

 

[Lloyd-ss]

Don't be afraid to use some special v-blocks or nests made out of maple or oak. I do it a lot with odd shaped parts that are difficult to clamp. Just make sure the part sits confidently in the wooden nest, and don't get greedy with the feed rate and depth of cut.
And be careful about climb vs conventional cut, and how the force from the cutter is going to push the part. Cut it in one direction and it pushes it harder into the nest. Cut it in the other direction and it tries to yank the part out, LOL. If it hasn't happened yet, don't worry, it will. And usually after you already have 6 hours into the part.

A lot of ingenuity in the suggestions already given.