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Author Topic: 9x20 Chinese Lathe Conversion  (Read 88548 times)

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Offline Dan13

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Re: 9x20 Chinese Lathe Conversion
« Reply #10 on: March 14, 2012, 01:55:28 PM »
Here is the bearing housing for the X axis:


I went for a needle thrust bearings arrangement here. It is two needle thrust bearings closed from either side of a step inside the bore. They are combined with a deep groove ball bearing at the end to provide axial support for the belt tension. Here is the section of the arrangement:


The reason for this over angular contact ball bearings is that angular contacts at that size are pretty limited in the axial loads they can take. The needle thrust bearings on the other hand can handle axial loads several orders of magnitude higher than the angular contacts. Preloading is fairly easy too. And as a bonus they are only a fraction of the price of angular contacts :)

The bearing housing will be mounted on the back of the carriage (as the motor is going to sit on the back). There are M6 mounting holes on the back of the carriage seen on the carriage picture.

The two bosses on the bearing housing are for mounting the motor mounting plate.

By the way, it's not shiny in the picture as it got treated with a light solution of phosphatic acid to prevent corrosion. Works well.

Dan
« Last Edit: March 14, 2012, 01:57:21 PM by Dan13 »

Offline Hood

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Re: 9x20 Chinese Lathe Conversion
« Reply #11 on: March 19, 2012, 08:35:11 AM »
Looking good Dan :-)

Hood

Offline Dan13

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Re: 9x20 Chinese Lathe Conversion
« Reply #12 on: April 08, 2012, 01:44:41 PM »
Thanks Hood!

Sorry for the slow update. Have been too busy lately.

This is the ball screw I am going to use for the Z axis:


It will be mounted on the front, where the original lead screw used to be. I made a mounting block for the ball nut out of aluminium:


The mounting block will be bolted to the bottom of the saddle. And here is the mounting block I made for the bearings housing:


The bearings housing will go into the round bore and the stepper motor will be mounted on the opposite side. I will be using timing belt drive between them. The elongated bore for the motor will allow for belt tensionning.

Dan

Offline Dan13

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Re: 9x20 Chinese Lathe Conversion
« Reply #13 on: April 09, 2012, 01:52:17 PM »
Made a ramp for triggering Z home switch:


It's made from steel and mounted on the bottom of the ball screw mounting block:


Also made a bearing support for the Z ball screw floating end:


Dan
« Last Edit: April 09, 2012, 02:03:18 PM by Dan13 »

Offline Dan13

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Re: 9x20 Chinese Lathe Conversion
« Reply #14 on: April 09, 2012, 01:59:50 PM »
Here is the X ball screw with a locking nut I made:


It's 12mm diameter 5mm pitch Hiwin ball screw, preloaded to zero backlash. And forgot to mention the Z ball ball screw specs in the previous post: it is 14mm diameter, 5mm pitch.

The ball nut will be mounted to the cross slide with this mounting block:


Dan

Offline Dan13

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Re: 9x20 Chinese Lathe Conversion
« Reply #15 on: April 12, 2012, 12:47:50 AM »
Bored all the timing pulleys. These is the X axis set:


It's a 2:1 reduction as I wanted to increase resolution on the X. The Z is 1:1 since I don't need that high of a resolution but better to have the speed there. This is the Z set with a key slot cut in the ball screw pulley (didn't have enough thickness after boring the 10mm diameter hole to allow for set screws as in the others):


And the spindle set:


Dan

Offline Hood

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Re: 9x20 Chinese Lathe Conversion
« Reply #16 on: April 12, 2012, 02:28:38 PM »
Coming along nicely, should be up and running by Monday :)
Hood
Re: 9x20 Chinese Lathe Conversion
« Reply #17 on: April 12, 2012, 09:25:04 PM »
 YES , monday, we will have a video of the lathe running and turning parts, can't wait to see ;D ;D


Jeff

Offline Dan13

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Re: 9x20 Chinese Lathe Conversion
« Reply #18 on: April 13, 2012, 04:31:36 AM »
LOL ;D

Would love to see it running by Monday myself, but there's a lot of work to be done yet. Next I am going to paint it. Then I am expecting the sheet metal parts to arrive next week and I will have to do some welding and then paint the enclosure and cabinet. Will then assemble it all and start working on the electronics. If all goes well and I don't get distracted by work I expect it running in about 3 weeks.

Dan

Offline Dan13

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Re: 9x20 Chinese Lathe Conversion
« Reply #19 on: April 18, 2012, 07:37:29 AM »
Got it painted:


I figured I wouldn't paint the aluminium parts. Wasn't sure how this paint would hold up on aluminium so figured I would rather have them anodized. So another little delay :(

Dan