Need Help!- linear control

[F3RR3T]

i am in the design phase of a 6'x12' router. and i am trying to decide which type of linear control would be the best but not cost me 6000 like thk rails would.

the main one i am stuck on is the one the gantry will ride on here is a picture for reference.



i have 128" span to cover


i am leaning toward the supported rail as shown here.

http://www.qbcbearings.com/BuyRFQ/LinearB_Rail_CCA.htm





v track was also suggested to me also seen here (what) keeps the the gantry from just lifting off when downward force is applied or the gantry tries to rock?

http://www.qbcbearings.com/BuyRFQ/Li...Track_VG_P.htm





this is what i wanted to go with originally but after being told that they are unreliable and need to be constantly rebuilt i decided its not for me (i was quoted around 6000 dollars for thk rails

http://www.qbcbearings.com/BuyRFQ/Li...Guide_R_ST.htm
http://www.qbcbearings.com/BuyRFQ/Li...Guide_B_ST.htm





basically i want something that will be accurate but doesnt need rebuilt constantly and wont cost me a arm and a leg. my budget for rails and bearings for the whole machine is 1000 dollars

[ger21]

Originally Posted by F3RR3T v track was also suggested to me also seen here (what) keeps the the gantry from just lifting off when downward force is applied or the gantry tries to rock? http://www.qbcbearings.com/BuyRFQ/Li...Track_VG_P.htm

You use two rails, one pointing up and one pointing down, with wheels above and below to hold the gantry in place. These would probably be your best bet, it's what Shopbots use.

[Regnar]

You could check out Arhens bearings as well. Cheap and effective. cncrouterparts.com

I know that on the Mechmate site they use the stepper with rack and pinion to keep the gantry from lifting aswell as the weight.

[Cartierusm]

I don't think there is anyway you are going to build that for $1000, don't get me wrong I hope you are able to get what you want but with electronics and the gantry it adds up quickly. Try these and see if they will sell longer lengths, they are like the QBC supported rail but way cheaper.

http://www.vxb.com/Merchant2/merchan...rMotionSystems

[F3RR3T]

Originally Posted by Cartierusm I don't think there is anyway you are going to build that for $1000, don't get me wrong I hope you are able to get what you want but with electronics and the gantry it adds up quickly. Try these and see if they will sell longer lengths, they are like the QBC supported rail but way cheaper. http://www.vxb.com/Merchant2/merchan...rMotionSystems

that budget is just for the linear bearings and racks.

[F3RR3T]

Originally Posted by Regnar You could check out Arhens bearings as well. Cheap and effective. cncrouterparts.com

i saw those. i thought about them but if i go that route i can make something similar rather quickly