R8 & 3/4” Shank Tooling Holder

[erikmannie]

Now I am going to side mill, as well as drill and chamfer so many holes in the 3/8” aluminum. That will consume the rest of today & maybe all day tomorrow. This turned out to be a project with a lot of drilling. I will upload pictures of this.

See below an old collet rack from which I am going to copy the hole size & chamfer.

 

[erikmannie]

I am using a cheap import 2 flute, 3/4” HSS end mill. The first cuts were .0115” and .020”. The RPM is 900. I know almost nothing about machining aluminum other than to turn up the RPM and use a 2 flute. My feed is about 14 IPM.

After two passes, the finish is gummy with with some chips welded to the surface. I will brush off the chips in the path of the cutter.








Maybe I should switch to a quality solid carbide end mill?

 

[erikmannie]

I made an adjustment: .0066” DOC, about 11 IPM and brushing off any debris in the path of the cutter.

I am very happy with this finish:



Wow, the camera is cruel on the finish! It looks great in person and awful in the picture.

 

[JimDawson]

Your setups are looking better. You are learning about clamping. Now you need to invest in some MDF to use as a backer board, a half sheet of 1/2 or 3/4'' from Home Depot or Lowes. Cut to size as needed. That way you can work directly over the table and no risk of hurting the table.

Parts bolted through the MDF to the T-nuts under.


As long as you have rigid setups, carbide cutters are great. That's about all I use now. For those edge cuts I would use a 3/8, 3 flute, aluminum cutting carbide. I rarely use larger than a 1/2'' endmill in my machine. About 3000 RPM and 20 IPM or so. Spray mist coolant, or just some WD-40 would be very helpful.

 

[erikmannie]

It looks like the issue was climb versus conventional. Look at the difference.

 

[erikmannie]

Your setups are looking better. You are learning about clamping. Now you need to invest in some MDF to use as a backer board, a half sheet of 1/2 or 3/4'' from Home Depot or Lowes. Cut to size as needed. That way you can work directly over the table and no risk of hurting the table.

Parts bolted through the MDF to the T-nuts under.
View attachment 413909

As long as you have rigid setups, carbide cutters are great. That's about all I use now. For those edge cuts I would use a 3/8, 3 flute, aluminum cutting carbide. I rarely use larger than a 1/2'' endmill in my machine. About 3000 RPM and 20 IPM or so. Spray mist coolant, or just some WD-40 would be very helpful.

Jiminy Crickets! That is *very* different from my cutting plan.

 

[mattthemuppet2]

Another suggestion, spritz the cut with wd40 or kerosene. It will reduce chip build up on the work and cutter, plus it helps flush the chips away. Smells nice too.

3 flute uncoated (HSS or carbide) is the way to go with alu

 

[erikmannie]

Your setups are looking better. You are learning about clamping. Now you need to invest in some MDF to use as a backer board, a half sheet of 1/2 or 3/4'' from Home Depot or Lowes. Cut to size as needed. That way you can work directly over the table and no risk of hurting the table.

Parts bolted through the MDF to the T-nuts under.
View attachment 413909

As long as you have rigid setups, carbide cutters are great. That's about all I use now. For those edge cuts I would use a 3/8, 3 flute, aluminum cutting carbide. I rarely use larger than a 1/2'' endmill in my machine. About 3000 RPM and 20 IPM or so. Spray mist coolant, or just some WD-40 would be very helpful.

Thanks for the tips. I got a huge improvement. I cranked ‘er up to 1700 RPM and increased the feed speed to about 23 IPM.

Unfortunately, I feel like I am too pressed for time to change the cutter.

I included a picture of the aluminum sheet that I have under the workpiece. The bottom of the shelf is a steel frame, and I figure that the steel is digging in to the aluminum sheet. I certainly don’t want anything digging in to the table!

 

[JimDawson]

Thanks for the tips. I got a huge improvement. I cranked ‘er up to 1700 RPM and increased the feed speed up to about 23 IPM.

1700 RPM is about 278 FPM on a 5/8 cutter, OK for aluminum. 23 IPM at that speed with a 2 flute endmill is about 0.0068 chip load, OK for a light step over, but getting it into the 0.002 range might give you a better finish. 10 IPM is 0.0029

 

[erikmannie]

I finished the side milling on the aluminum plate. I also drilled the 1-1/4” holes (for the .050” wall steel tubing posts). I had the aluminum shelves bolted to the steel (shelf) frames for all of the above.

Using Dykem, I located & marked out all of the 1” holes that hold the R8 collets. Some holes will be 3/4” for 3/4” shank tools. The steel frame is still bolted to the ally plate. It will be (blindly) drilled as needed.





I am using a stubby solid carbide 1” end mill that I got from @mattthemuppet2.