New Machine Build- Analogman's Data Cut Build Log

[analogman]

Hey all, just starting the process for building a data cut machine. I will stick close to the dimension of the plans, but perhaps use different rails and lead screws as they are cheaper from ebay. I just ordered the 8020 frame stuff and will definitely post pictures as I go along.

The purpose of the machine is low volume production of:
- roughing in acoustic/electric guitar bodies and necks
- specialized low volume printed circuit boards (very thick FRP and copper that cannot be made by PCB houses)
- engraved faceplates for electronics equipment
- wood speaker cabinets
- cut .080 aluminum sheet for electronic chassis

I have a few questions that y'all might help me with:

1) What pitch of x,y,z lead screw should I select given my intended purpose - or what factors do I consider when selecting the lead screw pitch.

2) The data cut machine uses continuous supported round rails on supports. The Y axis has a 1/2" backer plate. If I use a THK style linear bearing it may not be as rigid as originally designed. Should I make the backplate thicker?

3) The design calls for 3/4" round rails for X and Y, and 1/2" rails for Z. I can get cheaper THK style linear bearings on ebay - what size THK style should I get for X/Y (size 25?) and Z (size 15)?

4) What kind of spindle should I use for my purpose? The design says Dewalt Trim Router, engraving head or Bosch 1716EVS.

thanks for the help!

[analogman]

Well I ordered the 8020 for the router stand from 8020 garage sale store on ebay. Total cost was $462 not including shipping. Should be here in a week or so.

[analogman]

Well got some answers back from Chris:

(1) a 1/2" "lead" rolled lead screw will work fine for my purposes. Rather than a 1/2" diameter if I can find a 5/8" or 3/4" I will be able to handle higher speeds.

(2) The issue with smaller rails on the "Y" backer plate is not so much the rigidity, but to make sure there is adequate room for the Y lead screw. As well - I will need to modify the CAD files for the bearing placement, if they are not in the same position as originally designed.

(3) I have decided to use the recommended rails in the design as I will not have to modify the parts for different Y or Z rails.

(4) Bosch router would be suitable for the guitar work.

[CarveOne]

I looked at the Data Cut site last year when I was looking for a design to build. I still think it is one of the "cleanest looking" designs I found. The build cost was going to be more than I could manage, and I had some questions about whether the wood dust getting into the x axis rails was going to be a problem or not since the rails are level with the table surface. I'll be watching your build with interest. Maybe you'll convince me to reconsider it for my next build.

CarveOne

[analogman]

I really can't comment about the dust as I do not have one running, but the rails are actually upside down underneath the table surface. I think this will help quite a bit to keep the x rails clean.

I should point out that these are continuously supported rails anchored to the top - so there is no rail deflection.

[CarveOne]

Ah - excellent! That answers my question positively.

CarveOne

[ger21]

I've seen Chris recommend 2 turn/inchscrews on some of the yahoo groups, and that's becoming the standard for most routers built here. Roton has some reasonably priced 3/4" screws.
http://www.roton.com/Mating_Componen...family=7061226

[analogman]

Just purchased some 1" X Rails from ebay. The size of these will not affect the machining, other than mounting holes, so its OK for me to swap these out. $300 + shipping[PHP]

[analogman]

Holy cow - the "as designed" Y Rail assembly (which includes both rails precision connected) is $1100 and will take 5wks. Too pricey for me. I am going to buy something on ebay. This will require me to rejig all the mount holes and the Y lead screw bearing holes, Y motor mount and such. Rats, I didn't want to get into this, but I do want to keep below the $6000 mark.

[analogman]

Well I got some Thomson fully supported rails for the Y axis from ebay and some hiwin linear bearings from automationoverstock for the Z rails. Should be here in a few weeks.

I got a quote from Kerk for the lead screws and nuts. Their 60" TFE treated screw with antibacklash nut is $341. Roton is $120 (no coating and no backlash nut). McMaster Carr is $175 with wear compensating nut.

[analogman]

I spoke with others who had built the dataCut, as well as Chris, and some feedback from the board. Chris highly recommends Kerk, and has great success with heavy use. Others have used McMaster or eBay screws with nut from DumpsterCNC with good success.

I spoke with a Roton Engineer and he said they are just the same as Kerk, except Kerk has TFE coating - he said to make sure my screws are kept lubed and the performance and accuracy will be the same as Kerk.

I bought the lead screws and anti-backlash nuts from Roton (thanks Ger21) The nuts are Delrin and about the same price as DumpsterCNC. Total was $175 for 3 lead screws and antibacklash nuts. 1/3 the price of Kerk.

I also ordered up all the recommended belts, pulleys, cable carriers, and bearings from McMaster for $450 bones.

Now I just have to wait for the parts to come in, then adjust the CAD files to fit.

[analogman]

Since I will be using some different components than what the plans call for, I imported all the DXF files into CAD. Went together pretty good.