Tool Looking for blind bearing puller ideas

[Upnorth]

So a job that comes up often is the need to remove 2 small flanged bushings. They are installed in a lug from opposite directions so there is not much room to work. There is only a small gap about .100" where the bushing ends meet. The standard method is to get in there with a pin punch usually in an air hammer and knock out the first bearing then removal of the second is easy by pulling it through from the opposite direction. The second method is to drill the head off one bushing then drive the remains of the first bushing and the second one out together. Both of these methods are high risk to the casting the lug is mounted on. This part is probably worth north of $100k so getting rough with it is not a good idea. There is a repair to the bore for minor damage but this has it's own issues with custom bushings with special plating being required. Expensive and too long of a time frame to acquire.

Does anyone have any ideas for something that would make this safer and easier. I have had zero luck with the slide hammer type of remover they just slip off. The bushings are put in with epoxy primer. Protects the bore but makes them harder to remove.

 

[Susquatch]

Ask and you shall be helped...

This thread covers a lot of discussion about how to do it. Lots of tips and tricks here. Worth going to the beginning and reading everything. But here is a direct link to the final solution at post 203 for pulling a blind bearing easily. "This problem too will be simple when solved". Well worth reading all the early attempts too. Lotta content in that thread.

Post in thread 'Bridgeport Project' https://canadianhobbymetalworkers.com/threads/bridgeport-project.3521/post-48992

 

[Mcgyver]

I'm not following the description, can we get a sketch? Mostly bearings come out of blind holes hydraulically, but without seeing what you've got, no idea how applicable that is.

 

[Susquatch]

Both of these methods are high risk to the casting the lug is mounted on. This part is probably worth north of $100k so getting rough with it is not a good idea.

I missed that cost factor. If I understand your problem I don't think hydraulic methods will work.

The expanding collet fingers that I used in the thread I referenced above will work though. Especially if you have a 0.1" gap to put the collet finger claws into.

However, I used a Sliding Hammer Puller on the collet to get my blind bearing out. In your case with that much money at stake, I'd make a threaded puller instead.

You put the collapsed collet into the bore such that the expansion claws line up with the gap between the bearings, then push a threaded button into the collet to the right depth so the fingers are forced out into the gap, then remove the button push bolt and thread a larger bolt into the top of the collet and use a regular threaded puller on the head of the collet bolt to pull the collet and bearing out.

These photos might help but remember that thus is using a sliding hammer puller and you want a regular threaded puller.

Also, I had to use a a flush collet that grabbed the bearing chamfer. You have the benefit of a 0.1 gap to grab into. So your collet can be more robust.

If this isn't clear, I'll make a few quick sketches for you later today that will show the difference.

 

[Upnorth]

I'm not following the description, can we get a sketch? Mostly bearings come out of blind holes hydraulically, but without seeing what you've got, no idea how applicable that is.

I can make up a sketch soon. Probably won't get to it before Friday though. My one day a week that I get off so I will have some free time then.

 

[Upnorth]

I missed that cost factor. If I understand your problem I don't think hydraulic methods will work.

The expanding collet fingers that I used in the thread I referenced above will work though. Especially if you have a 0.1" gap to put the collet finger claws into.

However, I used a Sliding Hammer Puller on the collet to get my blind bearing out. In your case with that much money at stake, I'd make a threaded puller instead.

You put the collapsed collet into the bore such that the expansion claws line up with the gap between the bearings, then push a threaded button into the collet to the right depth so the fingers are forced out into the gap, then remove the button push bolt and thread a larger bolt into the top of the collet and use a regular threaded puller on the head of the collet bolt to pull the collet and bearing out.

These photos might help but remember that thus is using a sliding hammer puller and you want a regular threaded puller.

Also, I had to use a a flush collet that grabbed the bearing chamfer. You have the benefit of a 0.1 gap to grab into. So your collet can be more robust.

If this isn't clear, I'll make a few quick sketches for you later today that will show the difference.

View attachment 44354

View attachment 44355

I like this idea of the bushing in the end to keep the collet from collapsing. The slide hammer type I tried at work would collapse and pull out. This may prevent that. I should have pointed out that I do have access to the inside of the bore from both ends although it's limited in one direction. One low tech solution I'm considering is a custom punch stepped down a little so it can be rocked off centre to catch the edge of one of the bushings,

I did find this on the internet which would may be a good starting point.

 

[Susquatch]

Although a punch might work, that is a very expensive piece of equipment. I'd take the time to make an optimum solution and do it right. That's just my opinion. It's totally your call.

I took the time to draw something for you. You will have to adapt that to your situation, dimensions, and Puller locations.



Depending on the thickness, you might only need 6 slits. 8 is better and 12 better still. Do a dry run first to make sure it all works as intended. If you can't slide the expansion button in, the steel is too thick or the ramp is too steep, or you need more slits. When the button is pushed in the collet ears should spread because of the ramped nose and tapered hole. Then the insertion bolt is removed and a puller bolt installed.

Any screw type Puller will work although you might need to make an adapter between the collet threads and the Puller threads. Or just use a long bolt with a nut that draws the collet up through a home made Puller plate. Lots of ways to do that. It all depends what that area of your machine looks like.

 

[Johnwa]

How big is the bore?

 

[thestelster]

Are the bushings steel? Tig weld a makeshift slide hammer to the bushing.

 

[phaxtris]

i second how big is the bore ? is it a steel/stainless race ?

if its big enough, and steel or stainless, what i have done in the past with great success is just put a couple of beads on the race, its typically garbage anyhow, the weld beads shrink the race and it damn near falls out on its own

 

[Upnorth]

i second how big is the bore ? is it a steel/stainless race ?

if its big enough, and steel or stainless, what i have done in the past with great success is just put a couple of beads on the race, its typically garbage anyhow, the weld beads shrink the race and it damn near falls out on its own

Going from memory the bore is about .375 maybe .4375". The part is installed on a $35 million dollar airplane so using any sort of welder is definitely not an option.

 

[Proxule]

I understand the 100K cost, But I always used grease and a close fitting pin tapped in slowly ........ squeezing the bearing out,
Or use greased / wet paper towel and do the same method, Tap the mush in and keep adding more mush until the bearing is pressed out.
Can be mighty gentle if you go slow!

Gluck

 

[Bandit]

How hard are these bushings? Will a tap cut them for threads? If so cut threads from the side with easy access, rite through both bushings. Hook slide hammer on to bolt in first bushing to pull, use a bit of heat if can(??), (airplane parts). Or use the old piece of pipe/socket trick, socket against lug, threads long enough to extend through socket, some washers and a nut, pull first one out. Thread bolt into second bushing, drive out other side. All depends on how hard bushings are.
Maybe takes longer to one finger type then do.

 

[phaxtris]

Going from memory the bore is about .375 maybe .4375". The part is installed on a $35 million dollar airplane so using any sort of welder is definitely not an option.

That would be to small anyhow

There are plenty of welded parts on a 35$m airplane,if it were big enough I would Tig a bead on the race to shrink it up, it doesn't take much,and the heat stays very concentrated in the race, far less rough than a pin punch or an air hammer, but alas it's not big enough

 

[Upnorth]

I understand the 100K cost, But I always used grease and a close fitting pin tapped in slowly ........ squeezing the bearing out,
Or use greased / wet paper towel and do the same method, Tap the mush in and keep adding more mush until the bearing is pressed out.
Can be mighty gentle if you go slow!

Gluck

The bore is open on both ends so This would not work.

 

[Upnorth]

How hard are these bushings? Will a tap cut them for threads? If so cut threads from the side with easy access, rite through both bushings. Hook slide hammer on to bolt in first bushing to pull, use a bit of heat if can(??), (airplane parts). Or use the old piece of pipe/socket trick, socket against lug, threads long enough to extend through socket, some washers and a nut, pull first one out. Thread bolt into second bushing, drive out other side. All depends on how hard bushings are.
Maybe takes longer to one finger type then do.

The bushings are not hard at all. They are made out of some sort of slightly ferrous bronze. This might work except for the heat part. Even lodging a bolt into threads might give something to drive out from the other side without expanding the bushing. Good idea and worth a try.

 

[Upnorth]

That would be to small anyhow

There are plenty of welded parts on a 35$m airplane,if it were big enough I would Tig a bead on the race to shrink it up, it doesn't take much,and the heat stays very concentrated in the race, far less rough than a pin punch or an air hammer, but alas it's not big enough

You are correct there are many welded parts on an airplane. But you can't weld the part when it's installed on the plane. They are removed and sent to a shop for welded repairs. It's just how it is with aircraft. Airplanes have a lot of quirks. To remove any sort of electronic part you need to wear a special wrist band to avoid static electricity.

 

[Ironman]

I would use heat. A small torch tip to heat the bushing would do it. Bronze has a high expansion rate, and will expand and upset in the bore and when cooled will become loose.

 

[Susquatch]

The bushings are not hard at all. They are made out of some sort of slightly ferrous bronze. This might work except for the heat part. Even lodging a bolt into threads might give something to drive out from the other side without expanding the bushing. Good idea and worth a try.

I like the tapping the bushing idea. I would do that second though. Just because tapping it might weaken it enough to not be able to pull it. So I'd try pulling it first. Still a very solid idea and easy to do too. Wouldn't work with a bearing.

 

[Proxule]

The bore is open on both ends so This would not work.

Misunderstood.

Thanks!