# trailer spindle repair



## mickri (Feb 8, 2018)

When I bought my home a few years back the prior owner had left behind a very sturdy home built utility trailer.  This afternoon I decided to check out the bearings, etc to see if it was worth getting the trailer registered and start using it.  Jacked up the right side and the hub was very loose.  I thought to myself looks like I got a bad bearing.  Took it apart and the bearings were fine.  The grease seal looked like it needed replacement but I didn't notice anything else that looked a miss except it looked like the grease seal had been rubbing on the spindle backing plate.
Jacked up the left side and everything seemed ok.  Took the hub off.  No problems with the bearings and the grease seal looked like it needed replacement also but had not been rubbing on the backing plate.   Swapped the hubs side to side.  The right side hub on the left spindle fit just fine and was not loose.  But the left side hub now on the right spindle was loose and sloppy.  What's up with that???
I looked at the spindles and discovered that they were slightly different in one place.  The spindles have three bearing surfaces.  One for the grease seal, one for the inner bearing and one for the outer bearing.  The difference in the spindles is the length of the grease seal and inner bearing surfaces.  The left side grease seal bearing surface is approximately 3/8" long whereas the right side grease seal bearing surface is approximately 1/8" long.  And the inner bearing surfaces are different in length by the same amount with the right side being approximately 1/4" longer than the left side.   The inner bearing fits up against the face of the grease seal.  This is what keeps the hub in proper position on the spindle. There is no evidence of wear on the right side face.  Looks like it was made that way.

I think that I can solve the problem by machining a spacer to increase the length of the grease seal surface and decrease the length of the inner bearing surface.   I would think that this spacer would need to be a press fit.  Or would it be ok if it should happen to rotate.  The force of the inner bearing should hold it in place.  I would of course slather this spacer with wheel bearing grease.  Also how precise would the thickness of this spacer need to be.

Any and all suggestions would be appreciated.


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## Superburban (Feb 8, 2018)

Sounds like you have a great plan. I would make the spacer a tight fit, so it does not rotate. Check the seal is riding 100% either on whats left of the seal surface, or the spacer. If not, I would get one of those repair sleeves, so the seal has a good surface to ride on.

Thickness precision? I don't see it as that critical, as long as the bearing nut fully engages the threads, and does not bottom out on the threads. So I would say you could be off by 1/4" or so, and still get good nut thread engagement. I would concentrate on the seal surface, over the thickness.


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## kd4gij (Feb 8, 2018)

Post a picture of the spindle. Something isn't right.


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## mickri (Feb 9, 2018)

Going out of town early tomorrow morning.  Won't be able to get any pictures until early next week.  That is why I did the drawing.  Yes something is not right.  The spindles are welded to the axle and it looks like whoever build this trailer used two different spindles.  But that doesn't seem right either because the grease seal surface on the right side spindle  is not long enough for the grease seal to make contact.  It's a big mystery is all I can say.  I would rather focus on the repair than speculate on why or how the right spindle came to be the way it is.
The spacer would have to be fairly close to the correct width because it would determine where the load rests on the spindle.  It the spacer is too thick that would place the load further out on the spindle.   A repair sleeve is probably a good idea.  Just don't know if it would stay in place with the spacer.  I am thinking that I should make the spacer the same width as the left side.  This would guaranty that the grease seal would ride totally on the spacer and not on the joint between the spindle and the spacer.  That would place the load only about 1/8" further outboard

What material should I make the spacer out of? 

Thanks for the suggestions


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## mickri (Feb 9, 2018)

In making the spacer I am thinking about using a solid round bar and turn it between centers to the correct outside diameter.  The bar would be say 6" long and I would only turn the last inch or so to the correct diameter.  I would then use my steady rest to hold the outer end of the bar in place while I bore the inner diameter and face off the end of the bar.  Next cut off the end of the bar close to length and finally face off the bar to the correct length.
I have never done something like this before so feel free to point out any errors in my thinking or a better way to make the spacer.


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## jcp (Feb 9, 2018)

Sounds like a reasonable plan. I would make the i.d. a press fit. Either make yourself a tool to drive the ring on or heat it and slip it into place holding it for a few seconds until it cools enough to grab the spindle.


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## Tony Wells (Feb 9, 2018)

Spacers are best made, imo, by chucking a short piece and doing both the ID and OD in the same chucking. Face the part, generously radius or chamfer the end that will be on the inside next to the existing shoulder, or even bore the first 1/16" about +0.005 to assist getting in on straight. Then part it off. Stop before complete separation and put a 20° bevel on the OD to help get the seal on without messing up the lip. Sort of copy the other side as an example. Then complete the part off. If you don't want to change tools for the bevel, it can be filed on. Nothing too critical about it except smoothness, same as OD where the seal will ride.


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## 4ssss (Feb 9, 2018)

Shrink the spacer on and you won't have any problems.


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## Silverbullet (Feb 10, 2018)

It's just a stop for the bearing. It could be pinned on , shrink fit , or set screwed . It only matters there both the same width so the seals work and no slop when loading the bearings. They are taper bearings aren't they 1" I bet too. Normal small trailer . I've done many in my past . Even to the point of building from scratch , straight axles are pretty easy to take care of.


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## Groundhog (Feb 10, 2018)

Any of the above or a retaining product like one of these; http://www.loctite.co.uk/retaining-9171.htm should hold it. (just realized that is the European division, but you get the idea.)


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## Tony Wells (Feb 10, 2018)

Unlikely to be able to pin or screw it in place. The seal rides on the OD, so it should have a smooth finish.  Press, shrink and or high temp loctite or similar.

Could perhaps screw it thru the face if it were wide enough, but doesn't seem practical.


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## kd4gij (Feb 10, 2018)

And when he puts a spacer there. Good luck getting the cotter pen in for the castle nut.


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## dlane (Feb 10, 2018)

Ied go to the farm store and buy a known good axle with spindles and hubs.
I hate it when your trailer tire passes you up going down the road 
Use old axle as stock for other projects


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## kvt (Feb 11, 2018)

Be sure to check spindle and match the radius on your spacer.  most have a radius in the corner.  But heat/press fit should work, as there is not really any spinning force on it but the seal surface.  or at least that is what I see.


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## mickri (Feb 11, 2018)

The mystery continues.  Got back home late last night.  Took pictures of the right and left spindles today.


Left Spindle


Right spindle

  It appears to me that a spacer is part of the design of the spindle.  The left spindle definitely has a spacer and the right spindle does not.  The spacer on the left spindle did not want to come off.  But I didn't try very hard to remove either.  In looking at the right spindle there is a large radius from the spindle to the backing plate..  I have searched online and cannot find a spindle with a spacer. Or even just a spacer for a spindle. 
 The bearings are readily available and are metric.  Koyo 30206j-n Hi Cap. The inner bearing has a 30mm bore.   Because it is metric I am wondering if whoever made this trailer used spindles off of the rear axle of a front wheel drive car.  I'll search for cars that this bearing was used on.  I just might find the spacer.

Back to making a spacer.  What type/grade of steel should I use to make this spacer?

Thanks for all of the suggestions.


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## kd4gij (Feb 11, 2018)

Measure from the face of the shoulder to the cotter pen on both if there is room then make a spacer


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## mickri (Feb 11, 2018)

What type of steel do I make the spacer out?  Don't have anything on hand that is the right size.  I will have to buy it.  What should I buy?


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## cg285 (Feb 11, 2018)

mickri said:


> What type of steel do I make the spacer out?  Don't have anything on hand that is the right size.  I will have to buy it.  What should I buy?


how much do you use the trailer? i have a hub i make (rather vend out) that is 4140 forged and where the seal rides it is speced for induction hardening so the seal doesn't wear the hub - but this is designed for 100k plus miles in an expensive vehicle.

you will probably get a lot of answers that reflect what nasa would do but imo - in reality it probably isn't important what you use for this application. if you think you need an alloy and either case hardening or hardening i think you would be better off buying a replacement spindle or better yet a new axle. they don't usually cost that much


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## mickri (Feb 11, 2018)

This trailer won't get much use.  500 miles per year at the most.   Probably not even that much.  The occasional trip to the dumb or to pick up some landscape materials.  It is more just to have in case I need it.  I've had it for over 3 years and just getting around to looking at it.


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## cg285 (Feb 12, 2018)

mickri said:


> This trailer won't get much use.  500 miles per year at the most.   Probably not even that much.  The occasional trip to the dumb or to pick up some landscape materials.  It is more just to have in case I need it.  I've had it for over 3 years and just getting around to looking at it.



there you go. find a chuck of mystery steel and have at it. i guessing but i bet most trailer spindles aren't case hardened at the seal area anyway.
make it like tony wells said, give it a .0005 to .0015 interference fit, drive it on and forget it. if you screw up and make it a 0 fit peen the bore and use it.


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## mickri (Feb 12, 2018)

I am going to follow Tony Wells suggestion on how to make the spacer.  And I dug some more through my junk bin and found a piece of "mystery" steel that will work.  The length is about right but the diameter is way larger then necessary.  I will be taking off a fair amount of material to get to the correct OD.

A big thank you to everyone for their suggestions.


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## mickri (Mar 14, 2018)

I hope to finish the spacer today.  When I part it off should I part it at the finished width or part it oversize and then face it down to the correct width.  My concern with parting it oversize is scratching the polished OD where the grease seal rides when I face it down and then not being able to get the scratches polished out at the correct OD.  Forcing me to start over again.
Interesting to me at least is that the spacer is metric.  The OD is 45 mm and the ID is 30 mm.  When I measure the width today I'll bet that it is metric also.  The grease seals were hard to find and after a lot of searching found that there are off of an 80's Mazda B1800 to B2200 truck.  My auto parts store had to order them. 
Thanks for any suggestions.


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## cg285 (Mar 14, 2018)

i see no reason why you couldn't just part it off. once the hub is on no one will see that one side looks better than the other


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## coherent (Mar 14, 2018)

I built a small trailer a while back to pull behind my UTV for firewood hauling. I was surprised at how inexpensive the complete spindle and hub assemblies were with bearings and everything.  One of those things you have no idea the cost until you start researching I guess. I even found them on Amazon. That said, I'd be more likely to simply get a new one and bolt or weld it on than even mess with it unless you're just looking for a project. I guess I'm getting lazy in my old(er) age.


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## cg285 (Mar 14, 2018)

coherent said:


> I built a small trailer a while back to pull behind my UTV for firewood hauling. I was surprised at how inexpensive the complete spindle and hub assemblies were with bearings and everything.  One of those things you have no idea the cost until you start researching I guess. I even found them on Amazon. That said, I'd be more likely to simply get a new one and bolt or weld it on than even mess with it unless you're just looking for a project. I guess I'm getting lazy in my old(er) age.



they hand make 6-32 nuts here - just saying


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## coherent (Mar 14, 2018)

cg285 said:


> they hand make 6-32 nuts here - just saying


 Lol.. yep, the cost of fixing it 10 hrs work...  but the ability to say "I made it and fixed it myself for nothing"... priceless.  I suppose it's the main reason why we're here and have mills, lathes and tools to start with!


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## mickri (Mar 14, 2018)

I looked into buying a replacement axle and nothing I found would fit.  And a new axle would have required new wheels and probably tires too.  Plus more time to modify the trailer to make the new axle fit.  Easier to just make the spacer.  Also I like to fix things and would rather fix something than throw it away and buy new.


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## mickri (Mar 15, 2018)

One of the problems that I have had when boring a hole is that my holes tend to come out larger in diameter than what I thought they should be.  I use a Starrett telescoping gauge to get the inside diameter and then measure this with a caliper.  I have both digital and veneer calipers that I use.  Boring the ID on this spacer was a slow process and I had lots of time to think about this.  My conclusion as to the source of the problem lies in the telescoping gauge.  The ends of the gauge are basically flat and contact the ID on their edges.  Not in the center and there is always a small gap between the center of the gauge and the inside of the hole.  The smaller the hole the larger the gap.  I think that the ends of the gauge should be a round half circle of the diameter of the gauge and not flat.  If the ends were round you would get a true measure of the ID of the hole.  Or is there a way to compensate for this with resorting to trigonometry? 

Do they make telescoping gauges with round ends?  I have not seen any.  Or could I just round off the ends of the gauges that I already have?  I don't think that there is a enough material to do this.


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## cg285 (Mar 15, 2018)

mickri said:


> Do they make telescoping gauges with round ends?  I have not seen any.



i haven't seen any that are flat. mine are convex


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## Bob Korves (Mar 15, 2018)

The telescoping gages can be an issue, but usually the problem is with the less than rigid boring setup.  If you make a cut, measure it, and then follow it with another cut at the same setting, measure again, make yet another cut at the same setting, and measure again, you will find that the hole keeps getting bigger.  They are called "spring cuts" for good reason.  The springier the setup, the worse it gets.  When you get near your final size, use multiple passes before changing the setting, and check after each pass.  Another issue is having a good, sharp cutting tool set up with the proper geometry to make a keen cut, which will have less springing action.  For smaller holes, gage pins are my favorite way of checking progress.

I have never seen a snap gage with flat ends.  That would be worthless inside a hole.  Do not grind them, replace them!  Snap gages have their own idiosyncrasies, and a learning curve for getting consistent results.  There are plenty of tutorials on the web of how to use them properly, and well worth studying.  Practice with a known accurate sized hole until you can consistently measure within a tenth or two.  That is not easy, so be proud when you achieve it.


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## T Bredehoft (Mar 15, 2018)

Bob Korves said:


> I have never seen a snap gage with flat ends




Bob. So glad to hear you call them _Snap Gages_.  We always called them that at work, but *Telescoping *seems to be the common term here, _Snap_ or _Pop_, either one is fine with me.


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## mickri (Mar 15, 2018)

The ends of my Starrett telescoping gauges are not flat.  They are slightly convex and I mean slightly.  In smaller diameter holes the contact is on the edge of the gauge and not in the center.   If I look closely I can see a narrow gap between the center of the gauge and the diameter of the hole.  If the gauge had a truly round end that would solve the problem.
I thought that I would mention this for other newbies to machining who might also be experiencing in to this issue.


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## benmychree (Mar 15, 2018)

I too have never seen a telescoping gage with flat ends; perhaps you are thinking that they should have a full radius, when in fact, they are radiused to suit the smallest hole measurement in their range size.  Another thing is how you are using it; the procedure is to get it inserted in the hole at a small angle, then snug the lock up and rock it over center and remove it for measurement, then measure it with a micrometer, not a caliper, which can introduce small errors into the measurement.   
One might think I do not give enough credit for others not knowing how to use a telescoping gage, but I had to teach at least two employees to do it in spite of the fact that they supposedly had apprentice training.  You cannot feel around in a bore with the gage after the first "over center", the effect would be to cause the gage to telescope somewhat and lead to an undersize reading.


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## benmychree (Mar 15, 2018)

T Bredehoft said:


> Bob. So glad to hear you call them _Snap Gages_.  We always called them that at work, but *Telescoping *seems to be the common term here, _Snap_ or _Pop_, either one is fine with me.


Look in the tool catalogs such as B&S and Starrett, they are called telescoping gages in every catalog that I have seen, a snap gage is something completely different, they are a fixed gage for gaging outside diameters, measuring as a caliper does, and may have stepped measuring surfaces for go/no go tolerences.


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## mickri (Mar 15, 2018)

John, I take my readings just like you described and seem to get fairly consistent measurements.  
The spacer is done except for parting off.  I will do that tomorrow.  It was cold in my garage/shop yesterday and I don't feel like spending another cold afternoon.  Will part it off tomorrow.  Once this is done I will start on my taper attachment.  I have a separate thread for that.


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## benmychree (Mar 15, 2018)

Consistent measurements is what it is all about, good th hear that you are there; second point is that dial or digital calipers may be close, but so many times not close enough, for me, vernier tools can be trusted to a thousandth, if of a good make and condition; an old employee and friend refers to them, as his "very nears".


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## f350ca (Mar 15, 2018)

I've never seen flat ended ones either. This is one item where quality makes a difference. I had a chinese set that were rough, hours of deburring and polishing would probably made them usable. I bought a set of Starret that were surprisingly not that expensive. The difference was night and day. Smooth drag when setting them in the hole and snug up nice for the micrometer to measure them.
Measuring them with a calliper could be tough, the rounded faces sit nice between the flat anvils of a micrometer.

Greg


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## RandyWilson (Mar 15, 2018)

Coming in very late here. The spacer setup you have is very common where the engineers actually give a crap about fatigue life. A large radius on the spindle, then a slip fit spacer to provide the needed square shoulder for the bearing. You can likely pick up a replacement spacer (and bearing set) from your local trailer supply company.


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## benmychree (Mar 15, 2018)

f350ca said:


> I've never seen flat ended ones either. This is one item where quality makes a difference. I had a chinese set that were rough, hours of deburring and polishing would probably made them usable. I bought a set of Starret that were surprisingly not that expensive. The difference was night and day. Smooth drag when setting them in the hole and snug up nice for the micrometer to measure them.
> Measuring them with a calliper could be tough, the rounded faces sit nice between the flat anvils of a micrometer.
> 
> Greg


Yes, a micrometer is the most convenient tool to measure a telescoping gage with, dial or digital or vernier calipers also would serve, but as I said, are not the preferred tool from the standpoint of accuracy, at least in my experience I'd not trust any of them, except the vernier caliper any closer than a thousandth or two, especially for inside measurements; every dial or digital caliper that I have owned, whether Starrett or Mitotoyo that I have ever owned measured accurately with the inside jaws, always measuring undersize, I'd always stone the nibs off carefully until the ID/OD readings were the same.
I recently came by a set of B&S telescoping gages that have one handle and interchangeable heads; one nice thing is that they fit into a small box, taking up much less space than the ordinary type and also they have a longer handle than comparable Starrett models, and even nicer, there is an extra long handle that fits them, permitting measurements in deep holes.


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## mickri (Mar 16, 2018)

Randy, I looked and looked and searched and searched all to no avail on finding the spacer.  I was able to find  usable grease seals off of a Mazda truck.  But no spacer.  The spacer is metric, 45 mm OD 30 mm ID 8 mm wide, and the spindle is also metric.  Don't know what car the spindle came off of.  I also tried searching by the bearing part numbers without success as what cars they were used on.  This left me with no alternative other than making the spacer.


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## Bob Korves (Mar 16, 2018)

To get a good reading with a "TELESCOPING" gauge , first have a set that have not been abused or left to get rusty and filthy.  They will be hopeless.  Cheap ones are usually frustrating.  You want gages that lock with light pressure, and then the parts slide smoothly smoothly and evenly on each other.  If you crank them down, it will gall and distort them, and then you can throw them in the trash, worthless.  Whenever possible, get into a comfortable position where you can see clearly what you are doing.  Collapse the gage so it will fit in the hole.  Snug gently enough to hold against the spring pressure but not much more.  Get the gage inside the hole, rotate the gage until it touches both walls gently,  do not loosen the screw so the gage will "SNAP" into place.  The gage must not be close to center, but on a definite angle to the bore so the setting is bigger than the bore.  Then try to help get the gage in line with the bore, splitting it in half, no side loading or holding the handle off the bore center line.  It really helps if you have good access and a good view of the bore, and a comfortable position.  Success becomes easier.  Then pull the lever down part way, trying to let the plungers find the exact center of the bore, and snug it just enough to keep it from slipping, and when measuring it with the micrometer..  The plungers want to find center, and will, if you do not add loading and motions off the bore center line.  I ALWAYS (unless I can't avoid it) pull the handle smoothly DOWN, and smoothly swing the gage through the bore.  If it does not feel perfect, do it over, until it is as good as you can get it.  Then go to the micrometer.  If the mic is set too small, when you rub the plungers over the anvil and spindle it will change the setting.  Don't do that.  Do the measuring with the lightest of touches on mic and TELESCOPING gage plungers.  If you come against resistance, stop immediately, back off, open the mic a bit, and try again.  I find it easiest to hold one plunger stationary on the fixed anvil of the mic., then swing the other plunger against the mic spindle.  You want to make sure that you only get the perfect contact drag of the moving plunger in only one position on the spindle.  You must work the plunger in two axes trying to find the smallest distance achievable with the plungers on the mic anvil and spindle.  When you get that perfect drag in one spot, and ONLY in one spot, read the mic.  Start over at the beginning and see if you get the same number.  When you do, then take multiple readings of the same bore, until you consistently get the same number.  You want to be getting the CORRECT number, the actual size of the bore, or all is in vain. So use a bore that is a known standard, in good condition.  Multiple bore test gages of different sizes will help with real world measuring.  Eventually, TELESCOPING gages will be a SNAP, but only if you take the time to learn to do it right.  Someone good with TELESCOPING gages can measure bores within a tenth or two, day in and day out.  That is probably better than most can do with fancy bore gages, which are quite expensive and mostly stand idle unless you do that sort of work all day, every day.  Get a good set of snap TELESCOPING gages and learn how to use them...

Warning:  If you do not take the time to learn to do it right, you will have large errors and will turn much work into scrap...


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## dlane (Mar 16, 2018)

sounds like a good thread for the metrology forum  lotsa good info

So how did the trailer hub workout?


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## mickri (Mar 16, 2018)

I hear you Bob.  My gages are Starretts.  Lightly used and in excellent condition.  I am the 3rd owner of my lathe.  The original owner was a local farmer who used it to repair some kind of one cylinder pump engine as a hobby.   When he passed away it was sold to another local person.  The first owner went to my church and I found out through mutual friends that he hadn't used the lathe for several years before his death because of failing health.  The second owner never used it himself and it was only used a couple of times by a machinist friend of the second owner.  In fact everything I got with my lathe was in excellent condition.   When I got it home and looked it over there was not even a chip to be found anywhere.   The lathe had a coating of oil on everything and because it had not been used in several years there was also a layer of dust that had settled into the oil.  And it came with every imaginable attachment except for a taper attachment,  multiple chucks and tooling.  I think I paid top dollar for it but then again I didn't buy a worn out piece of junk. 
 I lucked into a mill/drill with a similar background.  I bought it from the estate of the original owner who had never used it.  Shortly after he bought it his health failed and it sat first in his garage and then in storage for over 10 years.  It didn't come with much except for a 15" Walther rotary table which wouldn't fit on the table of the mill/drill.  I sold the rotary table to a local machine shop for way more than I had paid for the mill/drill.  With what I sold the rotary table for my net cost on both the lathe and the mill/drill is less than $500.
My equipment doesn't hold me back.  Just my skill level which gets better every time  I use my lathe.


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## dlane (Mar 16, 2018)

Guess the trailer hub spacer didn’t work out a


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## mickri (Mar 16, 2018)

Don't know yet if the spacer is good or scrap.  I will part it off this morning and see how it fits.


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## mickri (Mar 16, 2018)

The spacer is a success.  It would have been a tight press fit when I first parted it off except I didn't have enough chamfer on the backside to fit tight against the spindle.  Good thing I didn't pound it home.  So I increased the ID by .001 and this allowed me to just barely slip the spacer in place to check the chamfer.  Increased the chamfer and now it fits very well.  I will have to loctite it in place to keep it from spinning.  Or I may use JB Weld.  I have time to think about this because it is too cold today, mid 40's, for either loctite or JB Weld to cure properly.



This is the side that goes against the spindle.  I purposely left it rough because I wanted it to have some tooth to help the loctite glue it to the spindle.  I might even ding the ID edges to make it more of a press fit. 



This is the front side.  I have polished both the OD and the front side.  So far I am at 600 wet or dry paper.  Next step is some jeweler's rouge with my dremel tool. 

All in all I am pleased with my spacer and how it turned out.  Another good learning experience.


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## cg285 (Mar 16, 2018)

do you reckon those chinese use jeweler's rouge when they make the spindles?


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## mickri (Mar 20, 2018)

Put the spacer on the spindle yesterday with red Loctite.  Put the hub and the tire back on this morning before the rain started.  Looks like I am good to go.

Thanks again to everyone for their suggestions.


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## cg285 (Mar 20, 2018)

mickri said:


> Put the spacer on the spindle yesterday with red Loctite.  Put the hub and the tire back on this morning before the rain started.  Looks like I am good to go.
> 
> Thanks again to everyone for their suggestions.



i think you were over thinking it from the get go. i/m sure it will be just fine. better than new


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## kd4gij (Mar 22, 2018)

All of the telescoping gauges that I have used are rounded on the tips, Even the cheap harbor freight set I bought first.  And I always use a micrometer for close tolerance work like that.

Post a picture of your telescoping gauge.


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## mickri (Mar 22, 2018)

My telescoping gages are Starrett No. S579H.  It is a set of 6 gages.  There is a very slight radius to the ends of the gages.  I doubt that it would show in a picture.  I was using the correct gage for the size of the hole and the edges of the gage would contact the hole and not the center of the gage.  I could just barely see a gap between the center of the gage and the hole while the edges were in contact with the hole.  Maybe the holes were too rough for the gage to touch on the center verses the edges.  I don't know.  IMHO which probably doesn't count for much if I had designed these gages I would have designed a much larger radius.


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## Bob Korves (Mar 22, 2018)

mickri said:


> IMHO which probably doesn't count for much if I had designed these gages I would have designed a much larger radius.


I think you mean a smaller radius.  As long as it is smaller.  Bigger is totally useless.  It does not need to be "much smaller", just smaller.  The radius of the gage plunger measuring surface needs to be smaller than the radius of the bore you are measuring.  If not, find one that is.


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## mickri (Mar 22, 2018)

You are right Bob.  Should have said a much smaller radius.


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