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Redrilling a figure 8 pattern 205

Hogback Fabrication

Hogback Fabrication

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I think I've asked this question before but I can't find it via the search (and it wasn't answered):


I have a 465/205 (10 spline, factory) setup currently. I've broken one 465/205 adapter and I'd like to make one that is stronger than the factory one and also design one that allows me to clock the transfer case up for a flat belly.

I'm considering a 231/205 doubler as well which involves a round pattern 205.

Here's the question I really need answered:

Since I have the figure 8 pattern 205 (and said adapter has mounting feet that hang pretty low and clocking is more difficult) I'd like to switch to the round pattern. Can you drill/tap the round pattern into a figure 8 pattern 205? I've read that you can and that you can't (i.e. the holes would protrude into the cavity of the case and could have sealing issues).

If the only issue with redrilling the case is the sealing issue I'm sure I could fix that.


Thanks in advance fellas :bow:
 
I've never done this, so I'm not much help but just so ya know. The LOMAX case has several sets of holes drilled in it. So i think you could drill another set if needed.
boltpat2.jpg
 
Yes you can drill the figure 8 pattern holes in the round pattern case. Several of the figure 8 pattern holes go into the case internals as it is. You just need to make sure you seal up the unused holes.
 
4X4HIGH said:
Yes you can drill the figure 8 pattern holes in the round pattern case. Several of the figure 8 pattern holes go into the case internals as it is. You just need to make sure you seal up the unused holes.
Click to expand...
he's doing it the other way around
 
muddermilitia said:
I've never done this, so I'm not much help but just so ya know. The LOMAX case has several sets of holes drilled in it. So i think you could drill another set if needed.
boltpat2.jpg
Click to expand...

The Lomax case is cast completely from scratch so I can't depend on that for my 30 year old 205 case :(

I appreciate it though :thumb:
 
I'm sure you also know about the different length np205 input shafts? round patern require the long input, but depending what you put this behind, you may be ok with what you have
 
muddermilitia said:
I'm sure you also know about the different length np205 input shafts? round patern require the long input, but depending what you put this behind, you may be ok with what you have
Click to expand...

Yep, if I make a 465/205 adapter it would still use the 10 spline coupler. It would clock the 205 up and the adapter would be less failure prone but would still use the 10 spline input/output/coupler.


If I make an adapter for the 465/231/205 I will have more research to do. I'm hoping I can use a 32 spline output on the 465 to a 32 spline input on the 231 (hopefully the 241 internals will work in the planetary section of a 231, I'm 95% sure they will) to a 31 spline input on the 205 (I have one, if that works it will save me several hundred $$)
 
38377k5 said:
Yep, if I make a 465/205 adapter it would still use the 10 spline coupler. It would clock the 205 up and the adapter would be less failure prone but would still use the 10 spline input/output/coupler.


If I make an adapter for the 465/231/205 I will have more research to do. I'm hoping I can use a 32 spline output on the 465 to a 32 spline input on the 231 (hopefully the 241 internals will work in the planetary section of a 231, I'm 95% sure they will) to a 31 input on the 205 (I have one, if that works it will save me several hundred $$)
Click to expand...
Sounds like a plan, I'm interested to see what you come up with
 
muddermilitia said:
he's doing it the other way around
Click to expand...

Damn, i really need to slow down on my reading. :doah:

So let me get this straight, he wants to drill the round pattern into a figure 8 pattern case and switch to the round pattern adapter? If so then i see no reason why that can't be done.
 
4X4HIGH said:
Damn, i really need to slow down on my reading. :doah:

So let me get this straight, he wants to drill the round pattern into a figure 8 pattern case and switch to the round pattern adapter? If so then i see no reason why that can't be done.
Click to expand...

That's correct, I have a (factory) 465/205 10 spline, figure 8 pattern setup.

I'm thinking about redriling my 205 for the round pattern in the hopes of (now or later) making some kind of drivetrain change: either the 465/205 clocked flat or a 465/231/205 setup

I swear I've seen people post (not necessarily on this board) that the figure 8 pattern 205 is thin in the area that would need to be drilled.


I am a fairly good fabricator and I have some experience with machining tools.





I guess I'm really asking if the figure 8 NP205 casting has as much material at the mounting surface as the 6 bolt round pattern. I've heard both ways :dunno:
 
I could check for you tonight as i have one of each bare case sitting in the garage.
 
I have both tcases outside.
I don't think it will work.
The figure 8 pattern case is kinda rounded, whereas the round pattern case has a large flat machined surface in the front.
I just set the round pattern adapter on the 8 bolt case and i don't see how you could get it to seal up, by simply trying to drill and tap the new pattern.
 
From the thread on pirate:

Figure 8 205:

figure8.jpg


Round pattern 205:

round.jpg



The figure 8 pattern 205 doesn't have material in what would be the lower bolt hole area (and sealing/mating problems would arise, as stated before).


Anyone know what kind of steel 205's are made of and if they're weldable?
 
I could but then I would have to find/buy a round pattern 205 :doah:
Click to expand...

I happen to have one. :whistle:

Not sure on how to ship something like that though. Not even sure it would be worth it for you.
 
4X4HIGH said:
I happen to have one. :whistle:

Not sure on how to ship something like that though. Not even sure it would be worth it for you.
Click to expand...

I'm sure shipping would be too expensive, they're pretty heavy.

I could build a 465/205 figure 8 adapter that clocks the t-case but if I want a 465/231/205 doubler setup I need the round pattern (unless I feel like building my own, which will probably take more time than its worth).

Really I'm just planning in advance and trying to discover some (apparently) lesser known info :dunno:
 
I had the following adapter made to bolt my figure 8 205 to my NV4500 . . .

cabwork009.jpg


Then you just plug the lower three holes in the tcase--or use them for an extra mount to support all the extra weight, like I'm working on :D

Not sure if this helps, since you're doing a doubler--for my application, it had to be thick enough to countersink one set of bolt heads . . . just food for thought . . .
 
Wrench said:
I had the following adapter made to bolt my figure 8 205 to my NV4500 . . .

cabwork009.jpg


Then you just plug the lower three holes in the tcase--or use them for an extra mount to support all the extra weight, like I'm working on :D

Not sure if this helps, since you're doing a doubler--for my application, it had to be thick enough to countersink one set of bolt heads . . . just food for thought . . .
Click to expand...

I know this thread is 10 years old now but where did you get the adapter made?
 
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