Is anyone using a cnc router to mill a chassis?
I could use a few pointers.
I have used mine to mill tag/turret boards in G10/FR4 with a little success.
I needed 3 different size holes in the boards.
I used a 1/16 end mill to cut .14, .093 and .125 holes. (#4 bolts, turrets and eyelets)
The holes were all a little small so I had to finish them up with a drill.
With a little experimentation I could probably get it to cut the holes properly,
The little end mill did a great job cutting the boards to the proper shape and size.
The chassis will be a Hammond 17x13x3.
It will be an Oddwatt designed class A PP Hifi amp with 4 KT150 output tubes.
I should be able to mill out the holes for the tube sockets(8), transformers(3), ics and heatsinks(2), bias test points and pots on the top.
I will have to make a cut out in my spoilboard so I can mount the chassis sideways to cut the iec socket, input and speaker jacks, switches, power lamps and fuses.
This should be interesting.
CNC router for chassis
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Stevem
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Re: CNC router for chassis
The gauge of steel used in the common chassis we tend to use does not lend itself well to milling since you have to feed too slow to just not bend it all out of shape.
If you do not want to go thru the expense of getting the proper size punches for the holes you need to make then a 1/2” drill bit and a 3 or 4 piece set of chamfering bits should get you through one chassis before they dull out.
I start with a 1/4” bit, then go to 3/8” and then 1/2” .
If your going with chamfering bits to reach your final hole size then try and layout the chassis so you can go in from both sides and your hole will be far more accurate.
If you do not want to go thru the expense of getting the proper size punches for the holes you need to make then a 1/2” drill bit and a 3 or 4 piece set of chamfering bits should get you through one chassis before they dull out.
I start with a 1/4” bit, then go to 3/8” and then 1/2” .
If your going with chamfering bits to reach your final hole size then try and layout the chassis so you can go in from both sides and your hole will be far more accurate.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: CNC router for chassis
I think those Hammond chassis boxes are aluminum. A CNC machine should easily cut aluminum. If you want to use a steel chassis, either you'll need a set of punches, as Stevem points out, or a proper mill.
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Stevem
- Posts: 4602
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: CNC router for chassis
I don’t know if a Aluminum chassis will handle the weight of the transformers to deal with really using the power to be had from 4 KT 150s, especially if it two per channel and then 3 transformers.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: CNC router for chassis
1/8" or 3mm Alu is sufficient for 4x KT150 transformers.
1/16" or 2mm Alu can handle 4x 6L6GC transformers.
Welding the corners prevent flexing for the latter.
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Stevem
- Posts: 4602
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: CNC router for chassis
His Hammond chassis is only .050" think, so that's not EVEN 1/16", since 1/16" is .062"!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: CNC router for chassis
It is an aluminum chassis.
.051 so it is pretty thin.
PT is 10 pounds.
OT is 7 pounds X 2.
I will brace the transformer mounts with aluminum angle underneath.
I have built dozens of chassis with a drill press and step bits.
Since I have the cnc router I would like to use it for this.
My smallest hole will be for a #4 machine screw.
My largest hole will be 1 1/4 for the octal sockets.
I also want to figure out how to mount the chassis sideways so I can mill out the iec socket and the holes for the switches, fuses and input/outputs.
This can wait.
I usually drill a hole between .1285(#30) and .152(#24) for the #4 screws.
This is to allow for the spacing of the mounting holes in the had drilled boards.
These boards were milled with the router so they are accurately placed.
My spindle is capable of running from 0-24000 rpm so I can run drill bits in it if I can fit them in an ER11 collet.
This chassis is 3" tall so I can't fit long drill bits.
My collets are 1/16 , 3/32 , 1/8 , 5/32 , 3/16 , 7/32 and 1/4. I also have 1-7mm collets but no bits or drills.
I have endmills in 1/16, 1/8 and 1/4.
Should I spiral drill all of the holes with a 1/6 or 1/8 end mill or should I do it in multiple runs using a 1/4 end mill for the larger holes?
Holes
65 .25 or smaller.
2 .375
6 .5
8 1.25
Thanks
Steve
.051 so it is pretty thin.
PT is 10 pounds.
OT is 7 pounds X 2.
I will brace the transformer mounts with aluminum angle underneath.
I have built dozens of chassis with a drill press and step bits.
Since I have the cnc router I would like to use it for this.
My smallest hole will be for a #4 machine screw.
My largest hole will be 1 1/4 for the octal sockets.
I also want to figure out how to mount the chassis sideways so I can mill out the iec socket and the holes for the switches, fuses and input/outputs.
This can wait.
I usually drill a hole between .1285(#30) and .152(#24) for the #4 screws.
This is to allow for the spacing of the mounting holes in the had drilled boards.
These boards were milled with the router so they are accurately placed.
My spindle is capable of running from 0-24000 rpm so I can run drill bits in it if I can fit them in an ER11 collet.
This chassis is 3" tall so I can't fit long drill bits.
My collets are 1/16 , 3/32 , 1/8 , 5/32 , 3/16 , 7/32 and 1/4. I also have 1-7mm collets but no bits or drills.
I have endmills in 1/16, 1/8 and 1/4.
Should I spiral drill all of the holes with a 1/6 or 1/8 end mill or should I do it in multiple runs using a 1/4 end mill for the larger holes?
Holes
65 .25 or smaller.
2 .375
6 .5
8 1.25
Thanks
Steve