Paul S
NAXJA Member #103
- Location
- Woodland Hills, CA
Anyone done it? I want to move my axle back about 2". According to Deaver it's a bad idea, but I have a hard time believing that it would lead to the demise of my springs.
Paul
Paul
-
Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.
Drilling leaf springs
- Thread starter Paul S
- Start date
BrettM
NAXJA Forum User
- Location
- michifornia
I've heard of leafs breaking as a result. you can probably get 2" by redrilling your perches, or definitely by making new perches.
if you do drill them, use a masonry bit.
if you do drill them, use a masonry bit.
Jeepin Jason
NAXJA Member #1100
- Location
- Lewisville, TX
I had to redrill the main leafs on my old leafs from Rusty's to move the axle an inch, and it was easy. All I did was redrill the main leaf and shifted the rest of the spring pack (only moved an inch, so no biggie), I figured that was easier than drilling every single leaf. I don't know if you could do that method for shifting the axle 2" though. Drilling the main leaf was really quite easy though, I had a much harder time drilling my crossmember for a t'case skid. I'm not sure what that says about the quality of Rusty's leafs at the time though, because I'd always heard that drilling "spring steel" was extremely hard and difficult to do, and that wasn't my experience at all...
Why are you trying to move your axle back 2"?
Why are you trying to move your axle back 2"?
RKBA
NAXJA Member #1012
- Location
- Outer Banks, NC
BrettM said:
Why the masonry bit?
I would use a good high end drill bit set, plenty of cutting oil and get busy with a DRILL PRESS.
Fabbing new perches is the way to go, all things being equal
BrettM
NAXJA Forum User
- Location
- michifornia
i read the masonry bit idea somewhere and when i had to enlarge the holes in a bunch of my leafs I tried it along with a normal HSS bit, the masonsry bit was much better.RKBA said:
Paul S
NAXJA Member #103
- Location
- Woodland Hills, CA
BrettM said:
That's what I was afraid of.
I don't want to relocate the springs on the perches. It may be a non-issue, but it seems like it would leverage the housing & possible induce axle wrap.
Paul
Paul S
NAXJA Member #103
- Location
- Woodland Hills, CA
Jeepin Jason said:
I figure that 2" is not enough to change the characteristics of the stock wheelbase (which I don't want to change), but it's enough to noticably improve the departure angle. + I have no sheetmetal, so I no longer need to keep my tires centered in the wheelwells.
Paul
Jeepin Jason
NAXJA Member #1100
- Location
- Lewisville, TX
Paul S said:
Not really. Even if you do something with the spring perches, the axle should still be bolted flush to the springs as normal. The end result is still exactly the same as if you go through and redrill all the leafs to move the center pin back 2". And actually, a longer spring mount would help reduce wrap some.
If you do something with the perches, you'll also have to redrill the u-bolt plate correspondingly, otherwise your u-bolts won't seat properly (they'll be angled forwards).
BrettM
NAXJA Forum User
- Location
- michifornia
it won't affect it at all
think about it, the center pin does nothing when the u-bolts are properly torqued down. whether you drill the springs or the perches, the axle and perches ends up in the exact same spot in relation to the leafs. there would be zero difference in leverage and axle wrap between the two methods. however by making the front half of the spring longer you do increase the axle wrap, which may or may not be an issue. farmermatt is running XJ leafs flipped around on his new buggy which makes the front half of the leaf really long, ask him if it created too much wrap, or you saw it working at BOTW...
think about it, the center pin does nothing when the u-bolts are properly torqued down. whether you drill the springs or the perches, the axle and perches ends up in the exact same spot in relation to the leafs. there would be zero difference in leverage and axle wrap between the two methods. however by making the front half of the spring longer you do increase the axle wrap, which may or may not be an issue. farmermatt is running XJ leafs flipped around on his new buggy which makes the front half of the leaf really long, ask him if it created too much wrap, or you saw it working at BOTW...
BrettM
NAXJA Forum User
- Location
- michifornia
Jeepin Jason said:
i'm not sure what you meant here, but it could possibly be read wrong.
ALL that has to be done is drill 1 hole in the perch, and 1 hole in the u-bolt plate. you will not need to, or want to, redrill the 4 big holes in the u-bolt plate.
Paul S
NAXJA Member #103
- Location
- Woodland Hills, CA
BrettM said:
Ahhh, I wasn't taking into account the u-bolts, or specifcally, the fact that regardless of the center pin location, the mount will always be centered over the axle. Thanks.
So that opens up the easiest option, which is those little 1/2" block, center pin relocater plate thingys. Only god for 1", but they would make it easy.
Matt's springs did not like the combo of running long side forward & without spring clamps.
Paul
FarmerMatt
NAXJA Forum User
- Location
- Down on the Farm
Redrill the perches Paul. Drilling the springs will be a nightmare.
Matt
Matt
5-90
NAXJA Forum User
- Location
- Hammerspace
I'm not going to say that your leaves WILL break if you redrill one or more, but I won't say that they WON'T, either. Here's a few tips for longevity.
Use the sharpest bit you can get, and keep it well lubricated. I'd use some sort of putty (modelling clay will work for this) to build a well around the drill site. Fill this well with a high-sulphur cutting oil (like Rapid-Tap or something similar) and make sure the drill site stays "under water." Also, don't push the drill thru - you want to "peck" drill, and take about 1/32" to 1/16" pecks. Why? This allows the drill and metal to cool, and allows for fresh oil all the time. Heat is the enemy here - if you do this right, you'll be able to press your hand on thr metal and hold the drill in the other hand when you're done. HEAT IS THE ENEMY!
Second, remember that any sharp edge - especially due to cutting - is a place for stresses to concentrate in metal. A change of thickness, width, cross-section, or whatever is a problem waiting to happen. Therefore, you want to make sure that you don't leave much in the way of sharp edges (I know the factory did, but they're more interested in saving money than doing things right. I'd sooner fire the damn accountants!) After you drill the hole, there's a couple things you can do to help it:
1) Countersink. At least this reduces the angles at the edges. You don't have to go deep - but do both sides. You want to break the 90* angle left from the drilling in half.
2) Edge rounding. If you have a buddy with a Bridgeport and a decent selection of tools, you should be able to find a radiused mill. It will take about 10 minutes per leaf - if someone knows what they're about - to put a nice radius on the hole. It doesn't need to be big, it just needs to get rid of the sharp edge. THIS IS THE BEST OPTION. If you're careful, you can probably do this with a radiused mill in a drill press as well - just something to think about.
3) Ball peening. Take a very large ball bearing (at least 3x the diameter of the hole,) set it in the hole, and give it ONE SOLID WHACK with a large hammer. Again, do both sides. This doesn't do as much for the sharp edge as a machining operation, but it will forge the metal at the edge of the hole and give the part a fighting chance.
Once you've done with that, it's a good idea to use some steel putty and THOROUGHLY fill the old hole you aren't using. It's not as good as no hole, but it's better than leaving the hold. You might want to countersink the edges of the old hole (both sides,) and use that to help hold the plug in while you work. Sand smooth. Remember, you really want to PACK the putty in so the hole is completely filled!
I know this is more work than the factory put into your XJ, but there's two good reasons to do it:
1) You're not doing "production" work, you're doing "custom" work - and that means you take a little more time to do EVERYTHING right!
2) 1* (for those of you unfamiliar with that sign, it translates as "One ass to risk." Meaning - don't take unnecessary chances! You see it from time to time on posts where I talk about structure and engineering. It's rare, and I haven't used it here in a while...)
5-90
Use the sharpest bit you can get, and keep it well lubricated. I'd use some sort of putty (modelling clay will work for this) to build a well around the drill site. Fill this well with a high-sulphur cutting oil (like Rapid-Tap or something similar) and make sure the drill site stays "under water." Also, don't push the drill thru - you want to "peck" drill, and take about 1/32" to 1/16" pecks. Why? This allows the drill and metal to cool, and allows for fresh oil all the time. Heat is the enemy here - if you do this right, you'll be able to press your hand on thr metal and hold the drill in the other hand when you're done. HEAT IS THE ENEMY!
Second, remember that any sharp edge - especially due to cutting - is a place for stresses to concentrate in metal. A change of thickness, width, cross-section, or whatever is a problem waiting to happen. Therefore, you want to make sure that you don't leave much in the way of sharp edges (I know the factory did, but they're more interested in saving money than doing things right. I'd sooner fire the damn accountants!) After you drill the hole, there's a couple things you can do to help it:
1) Countersink. At least this reduces the angles at the edges. You don't have to go deep - but do both sides. You want to break the 90* angle left from the drilling in half.
2) Edge rounding. If you have a buddy with a Bridgeport and a decent selection of tools, you should be able to find a radiused mill. It will take about 10 minutes per leaf - if someone knows what they're about - to put a nice radius on the hole. It doesn't need to be big, it just needs to get rid of the sharp edge. THIS IS THE BEST OPTION. If you're careful, you can probably do this with a radiused mill in a drill press as well - just something to think about.
3) Ball peening. Take a very large ball bearing (at least 3x the diameter of the hole,) set it in the hole, and give it ONE SOLID WHACK with a large hammer. Again, do both sides. This doesn't do as much for the sharp edge as a machining operation, but it will forge the metal at the edge of the hole and give the part a fighting chance.
Once you've done with that, it's a good idea to use some steel putty and THOROUGHLY fill the old hole you aren't using. It's not as good as no hole, but it's better than leaving the hold. You might want to countersink the edges of the old hole (both sides,) and use that to help hold the plug in while you work. Sand smooth. Remember, you really want to PACK the putty in so the hole is completely filled!
I know this is more work than the factory put into your XJ, but there's two good reasons to do it:
1) You're not doing "production" work, you're doing "custom" work - and that means you take a little more time to do EVERYTHING right!
2) 1* (for those of you unfamiliar with that sign, it translates as "One ass to risk." Meaning - don't take unnecessary chances! You see it from time to time on posts where I talk about structure and engineering. It's rare, and I haven't used it here in a while...)
5-90
gearwhine
NAXJA Forum User
- Location
- Denver, CO
I feel like everyone is making this sound much more difficult than it really is.
I have not completely redrilled my springs, but have enlarged the holes for a larger center pin, I use 3/8" now. I didn't use 7/16" because I couldn't find that size when i was doing this job. I will go back someday and put in 7/16". I used a high speed drill, drill press, and a lot of cutting oil. I drilled out 9 of my 10 leaves easily, and the 10th the bit went kaput, but that handy dandy drill doctor fixed it up right away. So, with that said, drilling the holes shouldn't be a problem.
next thing...Yes, sharp edges may cause stress concentrations, but come on, that really isn't going to matter in this case of bending. If the springs were really getting pulled on (tension) from bushing to bushing, then it would matter. Plus, if you counter sink each hole on both sides...the inner diameter of the hole will have less meat on it (i.e. sharper, and smaller area of contact on the spring pin) That pin will fail WAY before a spring break due to the stress concentrations, because...ya know...leave do slide around. Plus...the real world testing.....I've had mine drilled for over a year now without any special considerations (shot peening, counter sinking, etc), and haven't had any problems.
At first I didn't agree with brett's explanation that moving the spring pin position on the perch wouldn't change anything, but now I do. This will only be the case is the perch extends far enough back so the u-bolt doesn't start clamping the spring into thin air. it will also only work if you redrill the u-bolt plate for the center pin as stated before, so it clamps straight. If either of these aren't done, you will get extra stress/more axle wrap.
....now get a traction bar, and not worry about the spring wrap.
_nicko_
I have not completely redrilled my springs, but have enlarged the holes for a larger center pin, I use 3/8" now. I didn't use 7/16" because I couldn't find that size when i was doing this job. I will go back someday and put in 7/16". I used a high speed drill, drill press, and a lot of cutting oil. I drilled out 9 of my 10 leaves easily, and the 10th the bit went kaput, but that handy dandy drill doctor fixed it up right away. So, with that said, drilling the holes shouldn't be a problem.
next thing...Yes, sharp edges may cause stress concentrations, but come on, that really isn't going to matter in this case of bending. If the springs were really getting pulled on (tension) from bushing to bushing, then it would matter. Plus, if you counter sink each hole on both sides...the inner diameter of the hole will have less meat on it (i.e. sharper, and smaller area of contact on the spring pin) That pin will fail WAY before a spring break due to the stress concentrations, because...ya know...leave do slide around. Plus...the real world testing.....I've had mine drilled for over a year now without any special considerations (shot peening, counter sinking, etc), and haven't had any problems.
At first I didn't agree with brett's explanation that moving the spring pin position on the perch wouldn't change anything, but now I do. This will only be the case is the perch extends far enough back so the u-bolt doesn't start clamping the spring into thin air. it will also only work if you redrill the u-bolt plate for the center pin as stated before, so it clamps straight. If either of these aren't done, you will get extra stress/more axle wrap.
....now get a traction bar, and not worry about the spring wrap.
_nicko_
- Location
- Desert Beach So Cal
Too much overthinking. Redrill the main leaf and the #2 leaf for the relocated center pin. Keep the drill process cool and well lubricated.
The old and new leaf holes will be trapped within the clamp area of the u-bolt clamps. There should be little stress at either hole, old or new, as the force path through the combined clamped leaf stack will be a more direct route than through any single leaf. The friction between well clamped leaves will spread the stress through the leaf stack between the u-bolts.
Make sure you have strong u-bolts and leaf clamp plates. There are 5/8" u-bolts available for almost all tube diameters, and make your own plates from 1/2 stock (or stacked 3/8 stock).
You can also make new u-bolt plates (for above and below the leaf stack) with relocating holes, and even extend the lower plate length forward for a minor overload effect (or extend the top plate inward for a closer bumpstop rest). The result provides a little block lift, but it also allows a return to the old axle location configuration (no modification to the leaf pack, but more thought out machine work).
Expect to pull and mix and match the #3 and lower leafs until you get the feel you want. The extra leverage is not that much, but it will likely need tuning (or you may like the result enough to warrant more experimentation).
With all these experiments, you should be starting with cast steel leaf perches, not the cheesey heavy gage plate steel perches, welded to the axle tubes. Doing all the work and having the perch buckle on the first trail ride does not establish a fun repair chore.
The old and new leaf holes will be trapped within the clamp area of the u-bolt clamps. There should be little stress at either hole, old or new, as the force path through the combined clamped leaf stack will be a more direct route than through any single leaf. The friction between well clamped leaves will spread the stress through the leaf stack between the u-bolts.
Make sure you have strong u-bolts and leaf clamp plates. There are 5/8" u-bolts available for almost all tube diameters, and make your own plates from 1/2 stock (or stacked 3/8 stock).
You can also make new u-bolt plates (for above and below the leaf stack) with relocating holes, and even extend the lower plate length forward for a minor overload effect (or extend the top plate inward for a closer bumpstop rest). The result provides a little block lift, but it also allows a return to the old axle location configuration (no modification to the leaf pack, but more thought out machine work).
Expect to pull and mix and match the #3 and lower leafs until you get the feel you want. The extra leverage is not that much, but it will likely need tuning (or you may like the result enough to warrant more experimentation).
With all these experiments, you should be starting with cast steel leaf perches, not the cheesey heavy gage plate steel perches, welded to the axle tubes. Doing all the work and having the perch buckle on the first trail ride does not establish a fun repair chore.
