Hf 7x10 Spindle, Bearing, & Transmission Gear Replacement

If you don't have a spanner you can easily make one. I made one to use on my spindle nut. Looks like this.

spanner.jpg
 
Thanks Bill, if I don'the find another spanner this week I will give that a shot.

So, when all is said and done, I am assuming I will need to realign the headstock. Is there an Idiot's Guide out there (for the non-machinist)?
 
The headstock should align itself on the lathe. Just make sure everything is clean when remounting it.
 
I was able to remove the old spindle via my bearing puller and a few soft taps with a plastic dead-blow mallet. Piece of cake.

Parts were ordered and arrived today. Unfortunately, I only received one of the two bearings :cry:
The customer service agent at LMS was quite apologetic an is shipping the other one out ASAP, so all is well there.

I suppose that's actually a good thing; this will make me slow down a little and give me time to check everything thoroughly. This will also keep me from rushing the spindle / bearing fitting. I've got my wood lathe set up with a couple of oak dead centers; that should make the polishing process go a little quicker.


...Also packing the races in dry ice for a half hour or so would shrink them and make them go in easier. Just got to be quick doing it before they warm up. Our local Walmart sells dry ice. I've been known to put small housings in a 275 degree oven and dry ice the bearings. Then they just fall into place. Wife's don't like this!

Does icing the race have any down sides? Do they build up condensation as they are warming up, possibly trapping moisture between the race and the headstock casting?

Also, how bad will it smell if I put the headstock in our kitchen oven? If it's that bad, I have a propane smoker or a gas grill I could use instead. How long do I need to leave it in there?

Thank you!
 
I was able to remove the old spindle via my bearing puller and a few soft taps with a plastic dead-blow mallet. Piece of cake.

Parts were ordered and arrived today. Unfortunately, I only received one of the two bearings :cry:
The customer service agent at LMS was quite apologetic an is shipping the other one out ASAP, so all is well there.

I suppose that's actually a good thing; this will make me slow down a little and give me time to check everything thoroughly. This will also keep me from rushing the spindle / bearing fitting. I've got my wood lathe set up with a couple of oak dead centers; that should make the polishing process go a little quicker.




Does icing the race have any down sides? Do they build up condensation as they are warming up, possibly trapping moisture between the race and the headstock casting?

Also, how bad will it smell if I put the headstock in our kitchen oven? If it's that bad, I have a propane smoker or a gas grill I could use instead. How long do I need to leave it in there?

Thank you!

Depending on the ambient humidity there could be some condensation on the race. Just a quick wipe with a shop towel should clear that up. I wouldn't worry about it. The spindle housing will most likely stink up your kitchen. You never know what kind of chemicals the China-man used in that thing. If you remove the paint and all oil first it may still smell and give off dangerous fumes. My friend put his rear differential pumpkin in the kitchen oven. His wife damn near killed him when she came in. It did work for him though. A small propane torch- Bernz-o -matic is a good way to heat the casting. You monitor the temperature like use a non-contact infrared thermometer. You can also use a tempil stick. The old guys I used to work with-(hell I'm an old guy now) used to heat the housings until spit danced on the metal from the heat. That's about 275 to 300 degrees. You could also use an electric heat gun to heat the housing. I think that if you dry ice the races and just warm the housing to about 200 degrees or so you should be ok.

Sorry to hear about the bearing shortage. LMS seldom makes mistakes. They are are honest dependable people.

Roy
 
Sorry to hear about the bearing shortage. LMS seldom makes mistakes. They are are honest dependable people.
Yeah, a bit of a bummer, but really it's no big deal. They're making it right, and that's good enough for me.

Thanks for the info, and let the games begin!
 
The spindle repair shop where I worked used to just use a heat gun on the housings. They would prop the heat gun up to hit the bore and leave it for about 1/2 - 1 hour.
 
The spindle repair shop where I worked used to just use a heat gun on the housings. They would prop the heat gun up to hit the bore and leave it for about 1/2 - 1 hour.
That's probably what I will do as well. Much safer than me and any combination of flammable stuff :)
 
The new tapered bearings must slide on the spindle shaft in order to be pre-loaded. You could do this in a drill press by holding 400 grit wet/dry paper to the bearing seat areas on the spindle. Stop and check the fit frequently. They must be a palm fit to the new spindle. Just loose enough to move but not pressed tight.


So, about the fit of these bearings...
How hard should I need to push to get the bearings to slide? I've read the term "Push Fit" a number of times in conjunction with tapered roller bearings, but am still not sure (in practical terms) how much of a push should be required to move them. Push hard with both hands and something pressing the internal race, or slide with just a bit of force, one hand, no race tool needed?

Also, do both bearings need to be like this, or should it just be the rear bearing? It seems like one bearing that slides on the shaft would be enough assuming I understand the concept properly.
 
So, about the fit of these bearings...
How hard should I need to push to get the bearings to slide? I've read the term "Push Fit" a number of times in conjunction with tapered roller bearings, but am still not sure (in practical terms) how much of a push should be required to move them. Push hard with both hands and something pressing the internal race, or slide with just a bit of force, one hand, no race tool needed?

Also, do both bearings need to be like this, or should it just be the rear bearing? It seems like one bearing that slides on the shaft would be enough assuming I understand the concept properly.

The rear bearing should be easy to push on the shaft. No play discernible but the bearing needs to be able to move on the shaft. If you hold the shaft in one hand and the bearing in the other you should be able to slide the bearings into position easily with one hand. If the front bearing on your spindle is pressed on as far as it can possibly go, you still will be able to set the preload. So it is your choice whether to make the front bearing a press fit or a palm fit. The tighter the fit, the less chance of run out of the shaft. The idea is that you will use the spanner nut to pull the spindle and create equal pressure on both bearings. It's quite difficult to give an explanation that I'm happy with. You have two cone shaped bearings facing each other and their respective races. Tightening the nut pulls the front bearing into its race and pushes the rear bearing into its race. When the bearings are fully into their races as far as they can go you are at Zero clearance. Then a sixteenth of a turn more on the nut forces the bearings together under pressure. That pressure is the preload. This prevents any movement both axially and radially. On a differential pinion the same setup applies. The pinion nut is tightened and the bearing preload is measured as the torque required to turn the spindle after it starts turning. Usually that is 19 to 21 lb/in of rotating torque. It actually takes more torque to overcome friction/inertia to start the pinion shaft turning than to keep it turning. You have no way to measure the turning torque on your spindle so you get to the zero clearance point and then go a little further. The differential uses shims or a crush sleeve to set and hold the preload. Your spindle needs a lock nut to hold the preload that is why there are two spanner nuts. If you don't quite understand this, I'll try to make an easier description. Let me know.

[QUOTE="Also, do both bearings need to be like this, or should it just be the rear bearing? It seems like one bearing that slides on the shaft would be enough assuming I understand the concept properly.[/QUOTE]
Yes you do have that correct. You do understand.

Sorry if I have made it more complicated than it is. Feel free to ask any questions you have. I'm more than willing to help in any way I can. Make sure you lube the bearings. I've seen guys forget to do that. It sounds as though you are doing a great job your first time out.

Roy
 
Back
Top