Steel Table Assembly

[ckurak]

I am preparing for the assembly of a PRT120-60. I want to have all of the tools ready before the unit arrives. Also, I am trying for a high degree of accuracy during the setup phase to avoid as many problems later on as possible.

The assembly manual for the steel table indicates that a 6' level would be invaluable for leveling the table sides. My largest level is only 4', so I will be buying a larger level. However, the distance between the sides on a 5x10 unit is more than 6'. Woodworker's Supply carries a "ComPac 8' Expandable Level" (110-495) that expands from 4' to 8.5'.

Does any one have any comments regarding an expandable level, or another way to accurately level my table?

[rgbrown@itexas.net]

How about just buying a piece of rectangular Aluminum tubing to bridge the table and level that? Aluminum extrusions are quite accurate and affordable. A machinist level is more accurate than wood-workers levels. Perhaps you know where you could borrow one.

Ron

[gerald_d]

I would not purchase a 6' level to build the table. A 6' level is no more accurate than a 3' level.

I would purchase a 12' length (as long as your x-rails) of extruded aluminium rectangular tubing to use as reference straight edge - for getting the x-rails dead straight and flat. (I don't think a string is good enough).

Putting a 3' level on top of the extruded alu will give you better than a 6' level.

[charles48]

Charles,

I am a carpenter and very familiar w/ levels. Levels vary quite a bit. W/O going into telling you a how to tell a good level or getting something level with a not so good level I would recommend you buy a small Stabil. I have gone to different stores and checked these levels out and they are consistently good. The best I have found on the market. Get what length you want, but I would not invest in a 6' or longer level just for this setup. Take Ron's advice about the aluminum extrusions.

Charlie

[Normand Blais]

I have use a 1/2 inch clear water hose

[jkforney]

Charles
Did you finally make the plunge and buy a unit? Your first product should be selling the extensive notes you've taken. Welcome to the club.

John

[ckurak]

John,

Yes.

I did take a "few" notes at the Camp. :-) But I couldn't sell them. They need to be coupled with an in-person Camp experience. Thanks again for hosting the MidWest Camp ShopBot. The Camp was a great place to meet other present and future Botters, see a PRT and a number of accessories in action, hear many honest opinions, and receive helpful information from multiple sources.

Also, thanks to all of the Camp attendees. (You know who you are.) The Camp would/could not have been a success without your valuable input.

Thank you for the welcome.

[davidallen]

this is where one of those rotating laser levels comes in handy. set it up so that it's about 2" above your rails then you can use a piece of scrap to adjust all of the surfaces to the same distance below the line.

prices range from around $80 to over $300 at HD. I'd suggest getting one that's 'self leveling' but the main issue is getting all of your surfaces in the same planes.

[gerald_d]

David, I don't think that a rotating laser is anywhere accurate enough for this job. We used the alu. straightedge on top of the rails, and against the side of the rails, and used a feeler gauge between them.

[rgbrown@itexas.net]

I don't think one can go too far in trying to setup a machine tool being level and square. I set my ShopBot up using an optical level that was accurate to a millimeter at 100 meters. I've never checked it since. I'd bet it was off what it had been set to. I'd be willing to make the same bet on folks who have their machines on concretre floors unless deep piers and solid beams were employeed in the foundation. Another bet I'll take and win is a 3/4 inch piece of plywood will flex and lay on surface far more out of "specification" - whatever that means, than a ShopBot operator will allow. And, a sign cut from said piece of plyeood and slightly crooked table will be hard to distinguish from one cut on a straight and perfectly level table.

I suggest you use good careful technique and start making sawdust. Unless you need to make "Mil-Spec" parts, I doubt you will know the difference.

Ron