IPT too fast for old equip

[inthedark]

Can any of you give me a recommendation on what one should do when your calculated feed and speed exceeds the comfort level of your machine?

material is 6061, using a new 1" hog end mill.

Cut length 29.07" 4 flutes
depth per pass .125 cut width .4

I calculated about 1631 RPM spindle speed, and the IPM at 45.68 and IPT at .0070 (seems really fast)

I don't want to run the machine this fast. Since it's an 80's model mill. Do I slow the spindle speed and the IPM by percentages? Or will this shorten the life of my tool?

Even if I calculate using a .75 HSS end mill, the IPM/IPT still seems too fast for my mill.

Should I use an even smaller tool, on the theory that my mill is old, and I will only be able to cut at speeds the machine will bear?

Any thoughts would be welcome,

Kenny

[Rekd]

With alum, you should be fine using a percentage of the calc'd speeds/feeds. If you're machine doesn't have the horsepower, then yes, a smaller tool might be in order, or just lighter cuts.

'Rekd

[inthedark]

Thanks, I appreciate your time.

Kenny

[Rekd]

NP, let us know if it works out.

'Rekd

[Scott_bob]

[QUOTE]Originally posted by inthedark

material is 6061, using a new 1" hog end mill.

Cut length 29.07" 4 flutes
depth per pass .125 cut width .4

I calculated about 1631 RPM spindle speed, (SFM= 427)

and the IPM at 45.68 and IPT at .0070 (seems really fast)

I don't want to run the machine this fast. Since it's an 80's model mill. Do I slow the spindle speed and the IPM by percentages? Or will this shorten the life of my tool?

No end mill cuts smoother than a hog mill but:
A 1" diameter 2 Flute Inserted - positive angle - Helical shaped End Mill will last much longer, give better chip control, and be able to cut much faster...

Maximum RPM on your machine, say 7,500?
Feed at .007 chip load with the same depth of cut you're using...
Thats F105. (should be no problem)
Even if you have 10k spindle you could run at 10k and F140.

Even if you needed to reduce the depth of cut for horse power limitations you'd still be better off...

Good Luck,
Scott_bob

[inthedark]

My max spindle speed is 4200. Thanks for the reply you have given me the answers I was looking for.

Kenny