UPDATE! Harbor Freight X3 - 2/6/09

[caleb105]

Yes, I am aware of CadMonkey's excellent .pdf design. I have only been working on my Y axis conversion, and so far it looks fairly similar (L-shaped angled supports, bearing block, motor mount). However, I am making a few design changes. I modified my design so all pieces bolt together from the sides (instead of from the face). This way the axial force of the ball screw is applied as a shear force against the bolts, not against the threads. Also, I have been doing Finite Element Analysis on my design. The max force that the motor (387 in-oz Nema 23) could output converts to about 700lbs of linear force. Using 1/4" thick Aluminum for the side mounts, my design sees total Y deflection of .000025". Cadmonkey used thicker than 1/4" thick AL, and even included an upper support plate. This upper plate is not necessary with these levels of deflection, and would require an additional hole to be drilled and tapped in the saddle.

After seeing how small the deflection was using 1/4" AL, I started thinking about doing a design using steel plate (14-16ga) that could be cut and bent. That would save a lot of the milling time, and raw material. I made up another model using 16ga steel plate, and an inward force of 700lbs only produced Y deflection of .00005". However, this design would see the greatest deflection from an outward force (not backed by saddle), and I have yet to test that. If this design works, I have access to a CNC plasma cutter and may try to make a prototype.

I'm about 60% done with machining my Y axis conversion pieces. I just started working on designing the X axis. I noticed that the Solidworks Model I posted on my website (www.billetproof-engineering.com) has a slight error. The hole in the X axis ballscrew block (that bolts to the base) has it's threaded hole 3.7mm too low. This throws off the end bearing blocks in relation to the table and table holes. Sorry if this is confusing, but I'll try to post pics of everything soon.

-Caleb105-

[HackMax]

Caleb what did you use to compress the files on your website? I get unkown compression method error.

Thanks,
Rick

[caleb105]

Rick,

I'm pretty sure I just used Winzip. I'm making a few minor changes, and then will be replacing those files with a single .IGES file. Only one file to download, and you should be able to open it with Solidworks 2007 and maybe 2006.

-Caleb105-

[caleb105]

I just updated the link on my website. I have updated the model to include some slight changes I made to the model. I have also replaced all the solidworks assembly files with a single .IGES file. You should be able to open this file with earlier versions of Solidoworks or other modeling or FEA software. Here's the link to my website:

http://www.billetproof-engineering.com/?page_id=23

-Caleb105-

[jalessi]

Caleb105,

Very nice drawing.

Keep up the awesome work.

Jeff...

[Teyber12]

hey man, the drawing isn't working for me and i would love to have access to it. Any chance you could try to re-upload it?

cheers!

[Teyber12]

Originally Posted by caleb105 Thanks for the comments! I've been doing a bit of research regarding a high-speed spindle recently. I took my spindle into the shop today and had it pressed apart. Per the exploded view below, there are 2 main bearings used in the spindle. The upper bearing (#80 in diagram) is a deep groove single row ball bearing. It is model # 6006ZZ. The ZZ at the end of the model # indicates that it is double shielded. This bearing has an outer diameter of 55mm, an inner diameter of 30mm, and an overall height of 13mm. There are several companies that make this bearing (NWH, NSK, Timkin) and they all use the same model #. My mill happened to have NWH bearings. Note: Some bearings may only have 6006Z printed on each side. However, as long as it is shielded (NOT SEALED!) on both sides and BOTH sides have 6006Z printed on them, then this IS a 6006ZZ bearing! Here is a picture of a double SHIELDED ball bearing: And for reference, here is a picture of a SEALED ball bearing: The lower bearing (#79 in diagram) is actually a tapered roller bearing, despite the rendering in the picture below. This bearing is model #32006X. It has an outer diameter of 55mm, inner diameter of 30mm, and overall height of 17mm. Once again, this bearing is made by several manufacturers all using the same model #. Here is a picture of a Tapered Roller Bearing: I'm sure that by this point you're asking yourselves..."WHAT ABOUT SPEED???" This is the million dollar question. Per published data for the 6006ZZ, the limiting speed is 13,000 RPM. HOWEVER....this is NOT the ACTUAL limiting speed. It depends on what type of grease is used to lubricate the bearing. Most grease lubricants allow the bearing to operate anywhere between 60-100% of limiting speed. To be on the safe side, we will assume a cheap grease is used, and the bearing may only operate at 60%. This still allows speeds up to 7,800 RPM. We will quickly find however, that the tapered bearing is the limiting factor. Per published values, using grease, the 32006X has an actual limited speed of only 6,900 RPM. Therefore, there are several conclusions to be drawn from this: 1) It appears that all bearings of the same model # (2006ZZ or 32006X) fall under the same RPM constraints, regardless of which company makes them. 2) It appears that the stock bearings ARE capable of 6,000 RPM (possibly 6,500 RPM), but I would not recommend going any higher than that. 3) I have yet to determine the thermal impact of such an increase in speed. I am guessing that it requires active cooling, which is why the factory limited it to 2000 RPM in order to keep manufacturing costs low. I will be drawing up each internal spindle part in solidworks for future use by others. I have 2 presentations to give tomorrow, so I must now go work on those. I hope you find this information useful!

I ran my x3 spindle at 2x the speed for a long time, but recently did a vfd motor + belt drive and have been running it at 6k rpm's with 1/8" endmills in alu a lot. The bearings i noticed were completely destroyed... trying to turn the spindle around by hand was difficult.

I have completely disassembled the spindle and to my dismay have found all the buzz with people replacing their bearings is with the sx3 crowd, not the x3 crowd and they have very different spindles. Maybe this can become more x3 oriented.

My mill has been down for 2 weeks already and i want to get the show on the road here so i can keep cutting parts and making $. I have enough very expensive kluber grease for this project("kluber "Special greases for rolling bearings operating at high speeds and loads"
ISOFLEX NBU 15") in a syringe on my desk. I want to replace the bearing with very high quality substitutes and i can spend $150-200 if i have to on just replacing the bearings. I was wondering if:

1) is the quality the same between the NWH, NSK, and Timkin? (I have NWH on my mill) for both the 6006zz and the 32006x?

2) I cleaned and inspected the thrust bearing and found a huge score mark in there. i mean disgustingly gouged out of the race. i found this nice thrust bearing
http://www.vxb.com/page/bearings/PROD/Kit10701 with the same OD and height as my thrust bearing but with the bearing assembled the ID on mine is ~ 31mm, wheras the one in the link is 30mm. i know this is a thrust bearing and shouldn't matter but want to be sure. i checked for clearance when assembling the spindle and its fine.

3) Where is a good place to order bearings? I found these at vxb http://www.vxb.com/Merchant2/merchant.mvc? but there are two seemingly identical
nachi bearings, the "6006ZZE Nachi Bearing 30x55x13:Shielded:C3:Japan " and the "6006ZZENR Nachi Bearing 30x55x13:Shielded:C3:Snap Ring:Japan" but do not
know why or how a snap ring could be used here so i obviously do not understand the difference...

I found this about the tapered roller bearing
http://www.cnczone.com/forums/showthread.php?t=19033
but right now do not have the time to create an account and email the company in the link in the thread.

4) i could not get the upper tapered roller bearing race out of the quill. It looks like you couldn't either. When i replace the tapered roller bearing do i not include the op bearing race?

5) how do you remove the "shield" on bearings so i can re-pack the grease? and does the amount of grease to use depend on which grease is being used or is there a general rule (like fill 80% of space or something?)

Thanks so much for the help in advance.

cheers!

[HimyKabibble]

NSK, Nachi and Timken are all premium manufacturers. NWH I never heard of.

You *don't* remove the shields from shielded bearings. At least not without destroying them. If you're buying quality shielded or sealed bearings, you can assume they are properly lubed with quality grease from the factory.

Quality bearings are only half the battle. If they are not properly mounted, they will not last. And out-of-round spindle or outer race seat, or non-parallel seats will have the bearings mis-aligned, which will ruin the best bearing far sooner than its rated life would suggest. That's where putting good bearings in these poorly manufactured machines often turns out to be throwing good money after bad. Proper pre-load is also critical.

Regards,
Ray L.

[Arich0908]

This is where i getting ready to buy bearing they are site sponsors also.

http://www.bocabearings.com/main1.aspx?p=docs&id=37

[Teyber12]

Originally Posted by HimyKabibble NSK, Nachi and Timken are all premium manufacturers. NWH I never heard of. You *don't* remove the shields from shielded bearings. At least not without destroying them. If you're buying quality shielded or sealed bearings, you can assume they are properly lubed with quality grease from the factory. Quality bearings are only half the battle. If they are not properly mounted, they will not last. And out-of-round spindle or outer race seat, or non-parallel seats will have the bearings mis-aligned, which will ruin the best bearing far sooner than its rated life would suggest. That's where putting good bearings in these poorly manufactured machines often turns out to be throwing good money after bad. Proper pre-load is also critical. Regards, Ray L.

awsome thanks so much. i really appreciate you spending the time to go point by point with me Im glad i asked as i was quite wrong on several points! I will not waste my time with very expensive bearings. just something nicer then the chinese ones that would be $2.99 to replace that came with the mill.

and for the record, i found this timken 32006x roller bearing, but im going to to wait before i order the roller bearing.
http://kscdirect.com/item/TIM%2B3200...BASSEMBLY%250A
cheers