Newbie- BK/BF12 bearing how to install ?

[galoz]

hello,
this is my first post ..(so sorry for any mistakes)
i am in the proccess of building new and first CNC router table.
i buy from Chai on ebay a 1antibacklash ballscrew RM1605 with BK/BF12 bearing. it's for my first x axis machine.
i have some trouble installing the bearing, they impossible to fit by hand,
any1 know what is the right way to install the bearing, do i need to heat the casing or may be polish the shaft alittle bit ?

another question,when i screw the locknut of the BK on the end machine of the ballscrew it's seem not fully parallel, is he suppose to tight with the bearing (there is a rubber there , see in the pic i atached )?

thanx
Guy

[Action-KAT]

hi galoz
I hope someone gives u some help with this, I'm looking to buy from Chai too so would be good to know if there are any problems with the threads or the right way to fit them.

[scotta]

Guy,

I have the same bearing mounts and screw from Chai. His machining is a little on the tight side as my bearing mount would not slide on either. His response was to sand a little... I checked the machining with my micrometer and it appears that it is just the thread end of the bearing section which is a tiny bit oversized, mostlikely caused when the thread was cut.

The lock nut should be square to the shaft. It appears yours has a bad hole and thread. This nut should pull up tight on a metal spacer that spins inside the lip seal. Is this missing, there should be one on each side of the bearings.

Scott

[galoz]

hi Scott, thanx for replay.
you are right, the lock nut leaned against the metal spacer, and there is two spacer on of each side.
its seem that the spacer could be more high so the lock nut will not touch the rubber seal.. and also
my lock nut is not so square to the shaft ... so ..oh well i guess quality is not in the sky.
about the bearing, lot of peaple heat it to expand and the mount it on the shaft..
i found some info here : How To Install Angular Contact Bearing on Ballscrew.
** anyway i have a BIG problem that i only now notice .
my ballscrew is not straight !! since Chai can not send in with wooden box (due to customs problem)
i guess , some were in the way, the transportation mail was not very gentle with my goods ...
so goodbye to my distorted ballscrew.. it will never be like it came from the factory ..so i will not put any effort to straighten it.

BTW how did you install the bearing ? did you sand it ?
are you satisfied with the goods ?

[scotta]

galoz,

My ballscrew is only very short for my z axis so no problem with straightness. Sorry to hear about yours. Did you only get the one screw or several?

I have not yet fitted my bearing as I'm trying to get my design finalised and my spindle control sorted out.

Scott

[galoz]

Scott ,
i buy only one ballscrew for the X axis, its 1250mm long . i still need two more for the y & z axis.
i think now.. may be i should start on building from the Z axis and then by weight and figure to the y axis and to the long X axis for last. (i want the table to be constant and only the spindle move 3D)
BTW i ask for 16mm shaft, may be for 1250mm long the 25mm is more suit .

did you buy the Chinese spindle +inverter ?
i think Chai have a new inverter model..

anyway, about the bearing.. the BK/BF12 have a very heavy mount!! maybe for the Z axis use an aluminium house for the bearing, i saw a nice ballscrew with
bearing already pressed in over here :
http://cgi.ebay.com/ACME-1-2-10-Lead...item35a436895c

do you use a strong stepping motors ?

[scotta]

I have attached a pic of my z axis, nema 23 stepper and 1605 ballscrew. I purchase a 2.2kW spindle and inverter from Chai. I received the new brand Xin Ye but it did not last long so got a Huanyang which is of much better quality comparted to the Xin Ye drive.

The quality of the ballscrews seem fine. If you are going to buy more from Chai then I would suggest getting them all together. They can then be shipped together and would be less likely to get bent in transport.

Hope you build goes well

Scott

[15mgtar]

My 25mm ballscrew wasn't really straight either it vibrates wildly when I machined them. Oh and remember to push the rubber seal all the way in for the BK setup.
Am now trying to weld the chassis as I find it very difficult to weld with stick (molten metal only sticks to 1 side only most of the time).

[galoz]

thanx 15mgtar, yep i push the rubber and it good now.
i think to make the chassis from modular aluminium. BTW are you ok with the 25mm ballscrew vibrates ? the shaft is flexible abit ,but..

scotta, nice design of z axis !!
the new vfd inverter model Chai offer is called HLP A-series, is that Xin Ye model ?
i know Huanyang is what love-happyshopping ebay shop offer..
any way thanx for letting me know Huanyang is better

[15mgtar]

Hi Galoz, I haven't mount the ballscrews to the chassis yet because I just started to make my chassis (any tips on welding with stick would be great cause I got a real hard time welding with stick the 2 metal I tried to join just won't joint because the molten metal always sticks to 1 side only and not 2 mention joining in 90 degree angle).

[galoz]

15mgtar, here some tips i can tell you on general welding:
1. the two items must be polish and clean !! in the welding area.
2. they have to be from the same material.
3. maybe you need more welder current.
4. the secret of good welding is to keep constant distance (stick to material)

please upload some pictures of the welding

hope my tips will help you..