[reefy86]

forgive me for asking what might be a stupid question to you all but ive never dealt with slotted holes this way before and its quite important. this is just a rough template but say i make a plate that needs to have adjustment and i tighten the bolt like in the pic below, how do i prevent the bolt from slipping due to vibration over time?

Thanks

[CitizenOfDreams]

A flat washer and a lockwasher.

[Jim Dawson]

Once adjusted into to position and tightened, you could pin the plate to the frame. This is common in machine tool building to prevent lateral movement in assemblies.

[reefy86]

Once adjusted into to position and tightened, you could pin the plate to the frame. This is common in machine tool building to prevent lateral movement in assemblies.

thanks this would help

[reefy86]

How about the ballscrew, it is important that the ballscrew doesnt spin and i feel as if a nut at the end aint enough. i was thinking of making a plate that slots over the thread pretty much like a large washer and then tighten the nut once in position and then bolt the plate to the main mounting plate with the 4 holes to stop the ballscrew from moving left or right in the slotted hole over time. would this work?

[adam_m]

The ballscrew is designed to turn... that is how the machine moves. There should be bearings on both ends of the ballscrew.

https://www.phidgets.com/?tier=3&cat...=32&prodid=682

[StrawberryBoi]

If you want to prevent rotation, you can put a nut on both sides and clamp your mounting bracket between them, only use one to apply tension. As for preventing loosening under vibration in your first image, double-nut or a belleville washer would be better choices than the so called spring-lock washer shown above.

When working with vibrations in electrical cabinets or on vehicles, spring-lock washers are wholly discounted, they don't hold over time. A double-nut would be a thin nut first and a standard nut tightened down onto it, locking them together. You want to tighten the final nut until you start to feel that 'yield' sensation, that is when the threads in one or both sides begin to deform and it won't vibrate loose. You can also use a distorted thread lock nut. These are the kind that are all metal, no nylon thread lock features. They are usually a slightly ovoid shape. Only use them one time, if you remove the nut, use a fresh one in any locknut situation.

Belleville washer: https://www.mcmaster.com/belleville-...isc-springs-7/
Thin nut: https://www.mcmaster.com/thin-nuts/h...-nuts-grade-8/
Distorted Thread Locking Nut: https://www.mcmaster.com/locknuts/hi...read-locknuts/

EDIT: Just as a note, you want to tighten until the belleville just goes flat. The belleville provides the proper holding tension at that point. If you need a high range of compression for some reason, then you can stack bellevilles back to back. You can also use flat washers or either side of the belleville or both, if you feel your bolt head or nut don't make good contact with the belleville.

[reefy86]

The ballscrew is designed to turn... that is how the machine moves. There should be bearings on both ends of the ballscrew.

https://www.phidgets.com/?tier=3&cat...=32&prodid=682

Not when using a rotating ballnut or moving ballnut some may call it

[adam_m]

Not when using a rotating ballnut or moving ballnut some may call it

Indeed.

[reefy86]

If you want to prevent rotation, you can put a nut on both sides and clamp your mounting bracket between them, only use one to apply tension. As for preventing loosening under vibration in your first image, double-nut or a belleville washer would be better choices than the so called spring-lock washer shown above.

When working with vibrations in electrical cabinets or on vehicles, spring-lock washers are wholly discounted, they don't hold over time. A double-nut would be a thin nut first and a standard nut tightened down onto it, locking them together. You want to tighten the final nut until you start to feel that 'yield' sensation, that is when the threads in one or both sides begin to deform and it won't vibrate loose. You can also use a distorted thread lock nut. These are the kind that are all metal, no nylon thread lock features. They are usually a slightly ovoid shape. Only use them one time, if you remove the nut, use a fresh one in any locknut situation.

Belleville washer: https://www.mcmaster.com/belleville-...isc-springs-7/
Thin nut: https://www.mcmaster.com/thin-nuts/h...-nuts-grade-8/
Distorted Thread Locking Nut: https://www.mcmaster.com/locknuts/hi...read-locknuts/

EDIT: Just as a note, you want to tighten until the belleville just goes flat. The belleville provides the proper holding tension at that point. If you need a high range of compression for some reason, then you can stack bellevilles back to back. You can also use flat washers or either side of the belleville or both, if you feel your bolt head or nut don't make good contact with the belleville.

Thank you for the reply do you have a cad model to demonstrate this? If it wasn't for the rotating ballnut it would be simple by just having 2 fixes bk supports. Or does anyone have a picture of one they have done in the past? Not many rotating ballnut users out there unfortunately

[Jim Dawson]

I would use a threaded, clamp type shaft collar, and bolt that to the mounting plate.

https://www.mcmaster.com/bolts/shaft...shaft-collars/

[reefy86]

I would use a threaded, clamp type shaft collar, and bolt that to the mounting plate.

https://www.mcmaster.com/bolts/shaft...shaft-collars/

Interesting, would something like this work so it screws onto the ballscrew and then tightened and then bolted to the mounting plate or would this be significantly weaker then a nut?

Thanks

[Jim Dawson]

I guess that would work OK. You would just screw that onto the ball screw, then use a jamb nut to secure.

The alternative would be to thread the plate and just use a jamb nut to secure. The advantage of using some kind of nut that would bolt to the plate is that you could assemble it loose then do an adjustment for final alignment before tightening in place.

[reefy86]

Think i am going to go with this method i have done, ballscrew machined flat to prevent it from turning once plates are attached and then bolted through the ballscrew its self and then once adjusted in place then bolt all plates together. you think this will work well?

[Jim Dawson]

As long as the ''D'' is a tight enough fit on the ball screw, I don't see a problem.

[reefy86]

As long as the ''D'' is a tight enough fit on the ball screw, I don't see a problem.

Thanks that's good to hear

[reefy86]

Just one last question how do I know how much to tighten/preloaded the ballscrew?

Sorry for the questions

[Jim Dawson]

Just one last question how do I know how much to tighten/preloaded the ballscrew?

Sorry for the questions

I normally preload them to where I can feel a small amount of resistance when turning by hand. I don't know how to describe it, but maybe a little bit snug? There is most likely some specification published somewhere, but I have always done it by feel.. Maybe not the best way, but it works for me.

Short story: I was working on a machine with a German tech, there was a callout for ''normal tightness'' I asked the German tech what that was, he said '' Every good German tech knows what that is.'' Kind of the same as above.