Ah... OK. That makes sense. I was bothered with the Z axis as I said. Being 2.5" diameter, I see no problem Somehow I missed you saying the Z was 2.5" and it was only the X with the 0.75".

Dan

Nice little lathe Amazing how well it's preserved. It's 70 years old and looks better than some 10 years old machines I've seen.

0.75" diameter ball screws..? Sounds to small for a lathe that will cut 15mm per pass. Would expect twice that. At least for the Z.

Dan

Oh... one more thing. I am not sure how it works with G41/G42 offsets, so be careful if you're using them. Sometimes G41/G42 offsets don't like offseting of the coordinate system.

Dan

Hi Terry,

Good idea as always! I like your productivity.

Russ, do as Terry suggests for a stock you have and then it is fairly simple to tweak the G-code to accommodate for future stock changes. Let's say you do your G-code for a 4" wide stock - bottom parts aligned with the bottom edge, top parts aligned with the top edge. Be sure you first cut all the bottom parts and the move to cutting all the top parts. Let's assume next time the stock you get is 4.1" wide. You align the bottom edge of the material with the bottom parts' edge and the bottom parts are fine. Now the problem is with the top parts. Use "G52 Y0.1" before the code for the top parts. It will offset the coordinate system by that amount. Program "G52 Y0" in the end to cancel it.

Dan

What is the hole size? If it's big enough to put a substantial bolt in it (like 1/4"), then you're good. Bolt the stock down to a sacrificial plate (use enough for a pair like Sam suggested - you will have two bolts holding the stock), using the holes, then mill the profile leaving about 0.01" for the last pass - it is enough to hold the stock, but yet not to much to develop large cutting forces on the last pass, so the single bolt per part should handle it fine. Just tighten it firmly.

Dan

Assuming your machine is up to the task, as mentioned above, 3-flute carbide end mills designed for aluminium work best. They have very sharp cutting edge and milling on the side I can get very smooth surface seeing my own reflection. Using a good cutting oil helps a lot with aluminium to get a good finish.

Dan

The taper angle in your case will be:

tan^-1(((0.750-0.310))/2)/1.850)

BTW, cut a taper thread only once, couple years ago, and it worked fine with the simple treading wizard.

Dan

EDIT: Ha.. ha. You're quick Rich. You posted the answer while I was typing

You can use a subroutine right in the G code, like this:

test.nc
G01 X2 Y0
M98 P101
G01 X9
M98 P101
G01 X14
M98 P101
G01 X15 Y5
M98 P101
G01 X0  Y4
M98 P101
G01 X1
M98 P101
M30

O101
G1 A2.5
G1 A0
G1 A1.7
M99

Read the manual for more details.

Dan

Never said it was not going to work It's just not the common way to do this - press fitting a bearing in a sectioned housing...

Yes, we'll know soon how it works out. I guess no one has done this before, so your experience may help others. If anything, the biggest problem is going to be when using a 3mm part-off tool in alloy steel 30mm in diameter.

Dan

Hi,

1. my slide comes all the way out over the motor so unless i mount the motor backwards ill never have the room.

I know. I think it is worth considering.

2. the original mount is way to small for the new bearings.

Was suggesting to use the concept. Not the same mount.

I disagree as long as you have good bulk on ether side of the bearing your just not going to apply enough pressure to the bearing collar to get it to deflect, the inside has 200mm of cast iron slide and the outside had 30mm of Ali, im exposing probably less that 1/3 of the bearing which is hardened steel, the motors will give out or the belts will break before there is any significant deflection.

comments anyone with more experience?

cheers

It all comes down to the final rigidity of the machine. Motors and belts don't give you rigidity. Frame construction, mounts, bearings, slides and screws do. Your setup may and probably will work fine, but will be far less rigid than a proper steel mounting blocks. Depends on what you intend to be using the lathe for I guess.

Dan