welding a hole and tapping a new one in aluminum?

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hey guys, I'm almost afraid to post this here because I already know that many are going to say don't do it and it's not safe and all the rest of the safety police reactions but I really could use some inputI am doing a brake retrofit on one of my cars. the rear caliper needs to be moved down a bit relative o where the existing mounting bolts fall. I have machined the rear mounting pads to allow me to move the caliper lower, I can then just mark the new holes, drill and tap them, then even cut the extra ears with the old holes off. this I'm really not concerned about and I know will be fine BUT,my question is that there are a few different rotor diameters I can go with, and the larger rotor that I would rather use will wind up giving me holes that partially overlap these existing holes...now my question is, can the existing holes be welded closed completely, giving me a new blank pad to machine my new holes and tap, or is this really just not a good idea? I could remove the pistons and strip the caliper down to just an empty aluminum casting if necessary so the heat from welding them closed doesn't damage anything.realize that there isn't really so much pulling force on these bolt threads, the stresses this thing will see is sideways twisting, truth is even if the new bolt was not threaded then the 2 bolts almost act as shear pins and it would work even without threads as long as the bolts didn't fall out... I of course will be threading them but just want to show that the stress on the threads themselves is not so high, most of the stress is shearing against the bolts themselves...here is the caliper as it comes,  and the  approx place I'd need to bore new holes if I go with the smaller rotors, but I'd rather go with the larger which will wind up overlapping the existing hole a bit...ahh, tried to resize but don't want pics ruining my text so pics in next postmiller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:ok, pic 1 is factory setup with the approx location of the new trouble free holes optionand here's a shot of the mounting pad machined to allow me to move the caliper down to it's new position for mock upmiller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Weld heat will be on only one side of the piston bores, which could cause distortion.It's a given that disassembly is required, miking the bores before and after.The less heat, the better.That's an awfully thick ear relative to the hole size to weld up without seeing beaucoupheat input.Option might be to install slip fit AL plugs with chamfers on each end, plus some holechamfers, then bevel groove weld both sides of the chamfered pins and holesBlackbird
Reply:Have you tried finding different calipers that would fit?  If you found a different style caliper you may be able to make a new bracket to relocate the caliper rather than messing around with that casting.  Im doing a fork conversion on my bike right now that Im having a new bracket made for because the rotor I want to use is so much bigger than the one on the new forks.I am most definately NOT an expert on welding aluminum, in fact Im only now beginning the process of learning, but I have done similar things on steel parts and had it work.  Only thing I did was bevel the hole out real good to make sure I got in there and could get solid weld all the way up.
Reply:turbocad6If you are determined to do this consider cutting off the-now-excess ears through the center of the old holes.  This will give you an open trough to fill instead of a hole, and a high quality - 100% fusion - weld will be easy to attain  -  given the correct filler.Opus
Reply:I'd try to countersink both sides. Then build up from there. Let her rip!
Reply:Can't see pics from work but I would turn a slug in the lathe and then weld them in as stated above. I have fixed supercharger and intake manifold ears this way without any service life issues.T.J.Lets go Rangerswww.tjsperformance.comDynasty 300 DXHTP 240HTP Microcut 380Hyperthem 85JD2 Hyd Bender and HF Hyd Ring Roller all in one =(Frankenbender)Bpt. Mill/DRO4' x 8' CNC Plasma TableInstagram: tjsperformanceYT: TJS Welding and Fabrication
Reply:Originally Posted by OPUS FERROturbocad6If you are determined to do this consider cutting off the-now-excess ears through the center of the old holes.  This will give you an open trough to fill instead of a hole, and a high quality - 100% fusion - weld will be easy to attain  -  given the correct filler.Opus
Reply:Are you planning on having the calipers re-heat treated after welding? They are likely a 356 cast alloy which is a heat treated alloy. After welding the haz will be soft. You can tell right away because it machines gummy. Without heat treat you will likely compromise the integrity of the part. Welding leaves the part in a T0 state. It likely was a T6 from the factory. Now the bad news... getting a part through heat treat without changing the dimensions of the machined surfaces is likely impossible. Would I weld a caliper? I don't think so. It's possible you'd be ok in a T0 state... I don't know the part. I suspect the part would be stronger with the thinned wall than welded and soft.Another option, would be to machine a groove around the hole and then make custom bolts with a small lip that clamps in the groove, increasing the bit. Just throwing out ideas.
Reply:Here's a better thought for you maybe: Sleeve it with a steel threaded sleeve.Do the sleeve with a lip on the back end, and machine a groove in the hole area of the piston side so that when you pull on the bolt, it doesn't pull it through.
Reply:Presuming that the piston bores are steel or ss sleeved, the heat soak of weldingcan allow those sleeves loosen, then move or drop out of the bores-an un-welcomed surprise.Blackbird
Reply:How much into the old hole are you going to be overlapping?  You may be able to use a threaded style insert for the new hole.  They need a bigger size hole and tap to be put into for the original size bolt.  Depending what the offset of the holes are the new threaded hole may take up the original threads.  Some of the inserts come in an oversized OD as well.  I recently did this on a motorcycle hub to mount a different brake rotor to.  I would use a keensert or timesert style over a helicoil, but that is just me.
Reply:Could you weld a plate to the back side of it and drill for the new mounting hole? As long as there isn't any clearance issues...What about a new mounting bracket to relocate the caliper to the opposite side of the rotor?
Reply:guys, thanks for the input. opus that is a really great idea of how to approach welding these holes closed, when you said it a light bulb went on in my head, don't know why I didn't think of that  the camfered plug and chamfered holes seems to also be a good idea but... after reading forhires post I realized exactly how bad of an idea this is, and I'm really glad I posted this thread. I'd probably be better off just pressing a plug in and bonding it than welding but I'm not too thrilled with this idea either because of the location of the holes I'll require, aside from overlapping these holes quite a bit they are also getting too close to the edge of the mounting block, so even that is not going to work.as far as finding an alternate caliper, there really isn't anything else I can find equal to this 4 piston rear brembo caliper, short of spending 3 grand + buying a complete rear big brake setup made for this application. the front caliper I'm using is a brembo 8 piston monoblock so I really don't want to use less than this 4 piston rear, it's a perfect match to the fronts I'm using.  at this point I have 2 choices, either go with the smaller rotor which is pretty simple, just drill new holes above the existing ones, the new hole spread is 90mm apart where the old is only a 75mm spread, the new holes would wind up being centered ~20mm above the centering of the existing holes, this is the most straightforward way to do it. either that or cut the ears off of this one and build a bracket that bolts to the caliper and then bolts to the knuckle. I'd build the bracket out of steel, at this point I think this is the way I'm going to go with this, no welding to the caliper itself and building a bracket miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:this is aprox where the new holes would have had to beand this is where they would be if I went the easy way with smaller rotormiller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:can you modify the mounting plate instead of the caliper ? if not,the  size of the rear rotor is not nearly as meaningful as the front.miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:not really, the rear knuckle has 2 tabs that the caliper bolts to, I really don't want to even think about welding to the knuckle...I know the fronts are way more important than the rears, I believe the fronts account for ~70% of total stopping power on an average rwd or awd car,my front rotors are going to be huge though, there 15.4", I think the 13" rear smaller ones would be ok really, but I think I'd rather just do it once and go for the 14.3" rear rotors instead. also another thing that's making me lean towards doing the bracket is that I need to move the caliper back ~5mm or so, to do it with just retapping and bolting then I'll have to make the whole mounting boss a bit thinner to accommodate the 5mm moving in, where if I cut the caliper and make a bracket I won't have to do this and can leave the full existing thickness. the mounting tab is now 19mm thick, I don't know if reducing this to 14mm thick and just bolting it on is such a great idea either, I think I can get it to be sturdier with a bracket and also get the larger rotor on there too which is making me lean that way.... I'll try to draw up a sketch of the bracket I have in mind and how I have in mind to do itmiller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:1) Tap the existing hole 2) Screw in an a solid insert3) Drill a new hole
Reply:open the hole up, make an eccentric bushing, press eccentric bushing into hole..   drill and tap 3 small holes around the outer perimeter of the bushing and lock it in with set screws without welding..  you could also turn a shoulder on the bushing and counter bore the hole in the caliper so it wouldnt have a chance to push/pull through.  If you watch which side you put the set screws in and machine the shoulder in the bushing it will be  locked in location.use loctite 620 to seat the bushing, its stronger than the red locktite, just make sure its where you want it, that stuff is pretty much permanent. I would also safety wire the caliper bolts.tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:Originally Posted by leightrepairs1) Tap the existing hole 2) Screw in an a solid insert3) Drill a new hole
Reply:Could you just slot the hole with an end mill of the appropriate size. If slotted out correctly it will bolt down in the right place. I dont think it would move there would still be no way to move side to side. Just a thought.Making as much progress as a one legged duck in the middle of a pond, just going in circles.
Reply:Originally Posted by bruceropen the hole up, make an eccentric bushing, press eccentric bushing into hole..  you could also turn a shoulder on the bushing and counter bore the hole in the caliper so it wouldnt have a chance to push/pull through.  use loctite 620 to seat the bushing, its stronger than the red locktite, just make sure its where you want it, that stuff is pretty much permanent. I would also safety wire the caliper bolts.
Reply:I hear you about the inserts but the problem at this point is compounded by how close the new hole will be to the edge and the fact that I'd also have to thin this tab down a bit to properly center the caliper, I'd need to machine it from the 19mm thick it is now down to just 14mm thickwhat I am now considering is this... cut away all the black, mill the flat up to the new line shown, then use 4 M8 bolts where shown and have this bolt to a steel bracket. at that point I can leave the mounting tab at the full 19mm thickness because with as much cut away as shown the caliper can now be moved out as much as necessary because it would then be clearance'd enough to actually be completely above the existing mounting tabs. I'm going to sketch up my idea of a bracket but I think this may be thre most secure way of doing thismiller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Originally Posted by forhireAre you planning on having the calipers re-heat treated after welding? They are likely a 356 cast alloy which is a heat treated alloy. After welding the haz will be soft. You can tell right away because it machines gummy. Without heat treat you will likely compromise the integrity of the part. Welding leaves the part in a T0 state. It likely was a T6 from the factory. Now the bad news... getting a part through heat treat without changing the dimensions of the machined surfaces is likely impossible. Would I weld a caliper? I don't think so. It's possible you'd be ok in a T0 state... I don't know the part. I suspect the part would be stronger with the thinned wall than welded and soft.Another option, would be to machine a groove around the hole and then make custom bolts with a small lip that clamps in the groove, increasing the bit. Just throwing out ideas.
Reply:ok, this is what I now have in mind, cut the caliper down and machine the "flat" to be a bit wider like shown in the post above this one, then 4 bolts and a bracket like this:I think 4 M8 bolts will be as strong as the 2 M12 bolts that were originally used to mount this thing. does anyone think the 4 smaller bolt scheme would be weaker than the 2 larger bolts originally were? I think if this bracket is steel and I use all high grade hardware it should be as strong as it was at least... anyone think differently?miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....another sketch of the new bracket idea.shows how I moved the caliper in a bit over the knuckle's mounting  tab without having to thin the mounting tab to do it. I think this should be as strong as it originally was. I measured it to confirm and the original bolts are actually M14's but I  and I should be able to fit 4 M10's in my new setupmiller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:That was pretty much what I was going to suggest next. I was going to suggest machining the tabs off the calipers, drill and tap 2 holes on each side, maybe even drill and ream 2 blind holes and pin it with dowel pins, and bolt them on.  I was just going to run the bolts vertical instead of horizontal. To add to your tab design a little, you might drill and ream a couple of "Blind" dowel pins holes to lock the added tab in place.tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:You have a mill...What I would do is just make the existing holes slots to where they need to be..Then...Get some round aluminum stock to fill in the old hole that's leftover and weld in place just enough to hold them in..Then with the right size end mill just pick up the center of the new hole and finish the new hole.That's what I would do.Minimal heat and away we stop.BTW..You mention tapping..I don't see any tapped holes in anything shown......zap!Last edited by zapster; 05-15-2013 at 10:10 PM.I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I was thinking of pinning it, especially since the torque of the smaller bolts will be less, but figured using 4 bolts should be enough pinning really, and 4 M10's should provide enough clamping to prevent movement, maybe I could serrate one face to get a better bite without allowing any movement when torqued? . if I was still mounting to the front of the knuckle mounting tab then vertical bolts up would have been better but since I need to move it back slightly over the knuckle and I'd now be mounting to the rear of the knuckle tabs I think the vertical bolts from behind work out better in this design. I could go nuts and have 2 bolts from behind on the outer holes and then 2 bolts going up into the caliper on the inner and machine the bracket to contact both flats, but I think that may start to be a bit excessive and really complicate things, you think that would really be necessary here? I was also considering the possibility of instead of machining a flat to flat fit of caliper to bracket, maybe I'd be better off machining it as a notch to notch type deal, locking the 2 together better, but really the stresses on this thing don't really fall so much that way... I think the 4 bolts should be more than enough, and being much closer to the load, the leverage on them will be much less than even the stock bolt setup would have seen with those long mounting ears.I've been looking into material to build this bracket from, now I'm thinking of using 7075 T6 aluminum instead of steel for this bracket. the bracket itself doesn't necessarily have to have threads in it, the bottom 2 to the knuckle definitely just pass through holes, the 4 caliper to bracket bolts I'm thinking time-serts in the caliper. I'd rather not have the bolt heads be in board if I had the choice... if I did a steel bracket and put the threads in the bracket instead then I'd probably want to countersink the bolt heads inboard of the caliper, making the actual mounting flange that much thinner because of the countersinking but the threads would then be in steel... if I do 7075 T6 then this would probably need time-serts too, negating any benifit of bolting out to a threaded bracket.miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:zap, you were posting as I was and I just seen your post.. the holes in this caliper are supposed to be threaded but sometimes the steel bolts seize to the threads in a way that when the bolt is removed it kind of takes the threads with it... I think that's what happened here, there are traces of the threads left but not much I'm leary of what you suggest for 2 reasons, 1 is how close the new hole winds up being to the edge and 2 is that on top of this I would also need to make this tab a bit thinner to move the caliper in... after these things are done I don't think it'll be as strong as it was originally and a bracket would be a stronger end result...miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:as far as material selection for this bracket I'm going to order 7075 T6 unless I hear otherwise here. I've compared it to the existing caliper material, and assuming it is a 356 cast alloy heat treated to T6 then the 7075 seems to be much stronger overall, an ultimate tensile strength of 83,000 VS 38,000, a yeild strength of 73,000 VS 27,000 and a Brinell  hardness of 150 VS 80. it seems to have better properties than many steels, anything I'm missing here?miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:wow, I just went and looked at it again to take some final bolt measurements and you know what, your right after all man, there not tapped   there are some thread marks, and in my car they would have to be threaded as my originals are, so I just assumed they were threaded and stripped, didn't even look so hard at it till now, man I need glasses too miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:ok, I think I've come up with a final solution here and I'm really glad I posted this thread, it has really helped guide me to what I think will wind up being the best overall solution, only problem is I temporarily loose my parking brake .I've shown here the 2 different rotor positions I've been choosing between, the smaller rotor is a straight up drill and tap but it's just smaller than I want to settle for. the large one is the problem one I've shown, and the holes wind up too close to the edge for comfort, I don't think they'd good enough with just an insert and re-drilling, there's just not enough material left to still be strong enough.  so the whole bracket idea seems to be the only choice, but..... there is also a third rotor that is kind of usable here, it is sized in-between the small and large sized rotors, so medium I guess the reason why I originally dismissed this rotor is because it's from the latest model truck, and the latest model no longer uses a drum inside the rotor as a parking brake, instead it uses an electric actuated caliper parking brake thing. I didn't know that at first and I actually ordered this rotor and have them sitting in my shop right now, but when I seen that it didn't even fit over my parking brake and it had no drum surface is when I realized the whole electric parking brake deal. at that point I decided to just say screw it and just go with the large rotor, then I realized I may need to weld it, and thought that should be fine if I take it all apart and go easy, and that's when I decided to post this thread now, realizing why I can't fully weld it, and with zaps and all the other ideas of inserts in my head I decided to rethink the medium sized rotors fitment and measure it again. really that size rotor is just big enough, it's what I originally wanted for less unsprung weight...  well the medium sized rotor winds up putting the new holes 10mm higher than the problem holes. this is now well inside the tab, enough that it is no longer too close to an edge, and it only overlaps the existing hole by about 15%, as far as the thinning of the whole mounting boss from 19mm to 14mm is a little bit of concern but I may be able to squeeze a mm or 2 more out of this and 15-16mm should be thick enough. I wish I could take a few mm's off of the knuckle but that would be impossible with them mounted on the carthis final approach makes the caliper mounting much easier and eliminates the need for brackets and a lot of complications, but instead, now I'm going to have to get a parking brake caliper setup and make a bracket for that and rig something up there   I think I'm a little more comfortable making my own parking brake bracket than actual braking caliper bracket I guess, and maybe I can think of an alternate parking brake scheme too, a line lock could work maybe... don't really need a parking brake much tbh, I guess I could just keep a few bricks or blocks of wood in the trunk too either way this makes my life a whole lot easier right now at least, I do loose a parking brake temporarily but now I don't even have to fight with the Mercedes dealer to take back the rotors I made him order for me and order different ones toohere is roughly where the new holes will fall, this is what I originally machined my flats for, before I realized the whole parking brake problem  the washers are exactly like the bosses on the knuckle....and this is where the holes would beit really does look like threads at first glance ok, so now to do an insert, do I freeze the plug and heat the caliper for a tight interference fit? if I do freeze the plug and get a really tight interference fit do I even need to weld at all? will just a little welding on the edges to lock a plug in place not cause a problem? what should I even use as a plug? the hole is ~.475", how tight should I make the plug? can't I just bond one in?miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:I could also go back to brucers original idea of an offset insert threaded and flanged but not sure how I'd even begin to machine something like that with any kind of accuracy. this new hole location does allow a lot more possibilitiesmiller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Originally Posted by turbocad6I could also go back to brucers original idea of an offset insert threaded and flanged but not sure how I'd even begin to machine something like that with any kind of accuracy. this new hole location does allow a lot more possibilities
Reply:I knew they were not tapped..If they were they would not be called "Free Floating calipers" now would they?They just mount to the rods and the end of the rods are threaded and they bolt to the holding bracket.Myself I would just do what I stated at first but that's just me..Glad to see you are on track anyway....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:zap these aren't free floaters, there 100% solid fixed mount multi piston. if they were floaters then they'd have another support bracket and these bolts would only be an alignment/slide guide type thing, but these are solid mount bolted, no additional support bracket at all and these mounting holes are the only thing mounting these solidly to the knuckle. the car they came off of had the threads on the knuckle but on my car I'll have to thread the caliper or use a threaded nut on the inside I guess... a threaded nut might be better because then it won't rely on the strength of the inserted plug at all, it'll just be compressing it and the plug won't need to do any more than just be there as a filler more than anything... I would do what you are suggesting but I'm afraid of the heat ruining the metal now so I'm thinking tapping and screwing a plug in sounds like a good idea to me... I guess I could tap and screw and then minimal weld to keep it in place rather than lock tite it, shouldn't be too much heat for just a little bit of welding, just enough to lock the threaded insert I guess but if I do use a bolt and nut then I think I should be fine with no welding at all...thanks guys for all the input, it is greatly appreciated and I'm glad to have on line friends like you guys, really helped me reach my best solution here miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Whatever route you take once it's in place it really can't go anywhere anyway right?I left out the "Dutchman" route..You could always do that with (2) 8-32 set screws for each insert..Do you know what a Dutchman is?Just asking....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:no idea I'm def just going to bolt and nut this, takes all of my guesswork and worrying right out of the picture, with steel bolt and nut I could just about leave the existing hole as-is and it would still be fine. I'll just need to cut part of the backing plate out for room for the nuts, no problem now since I'll be gutting the parking brake anywaymiller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Pardon my bad drawing I'M no artist..Just drill and tap along the insert seam and install the screws and then it's locked in place with no heat involved..Only drill and tap about 1/4..3/8" deep dont break thru to the other side..When adding the insert to the existing hold do it with .001 press and put them in from the inside out with a rubber hammer and a drift so the part getting the insert is against the bench so it won't crack/break.We use dutchmans alot on new sleeves on stuff you can't weld and they are very strong.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:cool, I'm going to play with this tonight... I'll pick up a few tiny allen key lock insert things and a small tap & die and do what you're showing there, I also am going to play on the lathe and instead of just using full nuts inside I'm going to turn the nuts down to a flanged sleeve insert so the nut isn't protruding so much on the inside yet still give good thread engagement, now it'll only protrude as much as the flange I leave    thank you miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:All you need is set screws.Nothing fancy just plain'ol screws and just make sure they are flush or just below the opening.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:ok, I tapped the holes, threaded some aluminum bar and made inserts to fill the holes and loctited the new plugs in... I also removed my whole parking brake assy and cut the mounting tabs off so the rotor could sit flush so I can get a really precise new hole location, and it turns out that the new hole winds up falling completely above this existing plugged hole.i didn't pin them yet, truth is I really don't even think they even need to be pinned at this point but I might just for the hell of it.now my last dilemma here,,,turns out that I need to still move the caliper inboard a bit, final measurements puts this at me needing to remove 6.5mm from the mounting boss which is now ~19.5mm thick.... now I'm really not worried as far as the strength as even at 12mm thick I know the mounting bosses will be strong enough, what I'm more worried about is the strength of the threads in aluminum at only 12mm thick, I could use time-serts or whatever but even so, were still not changing the fact that there are only 12mm of thread engagement.   what I have been playing with now is to instead of directly threading into the aluminum, to instead use steel threaded bushings... I made a few from lug nuts, idea here is that the steel threads will be stronger than in aluminum an the flange at the back of this bushing will have this working as if it was a bolt and nut, I'm just a little unsure of if this would wind up being stronger than if I just threaded it into aluminum and also not sure if I thinned this bushing down too much and if it's still strong enough, so I would really like to hear opinions on this bushing design VS threading straight to the aluminumshould I have left a little more material thickness on the flanges here? this is where these bushings will sit, the bushing is really just a recessed nut with a flange and it completely misses the original hole, no overlap again, these mounting ears on the caliper will still be machined down from the 19.5mm thickness they are now, down to 12mm thick, which is why I have concerns about thread strength...miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:I like the progress. Good call on turning down the lug nuts... I'll have to remember that. You could put a straight knurl on them press them in just like a stud. I really think a retaining compound like 620 locktite would do it without issue. I have some 609 in single use (0.5 ml) applicators left over from a job. It's not as high temp as 620 as it's designed to be removable. Send me a PM if interested and I'll drop a few in the mail. Check the spec sheet:http://www.useloctite.com/filephotos...ions_Guide.pdf
Reply:press fit would be good but I think I'm going to simply thread the outside of this bushing with an M16x1.5 thread and then thread the new hole in the caliper too, making my own steel flanged threaded insert   the red loctite thread locker I'm using is temp resistance rated to 360*F continuous and is the more permanent, not made to easily take apart kind....  the caliper mounts will never ever, ever really see above 360*F in continuous use, and truth is, even if all the loctite completely melted clear off of this thing it would STILL be mechanically locked together as an assy with no dependency on the thread locking at all because of the level of torque and the compression as assembled, so  like zap says it def isn't going anywhere ....   mick for me the problem I think with just threaded inserts alone with only 12mm of total engagement on an M12 bolt is that aluminum threads are pretty weak unless there is a good length of engagement, and when you get down to the point of only 8-9 threads of engagement in aluminum you're limited in how much you can torque the bolt down and still have shear strength. even an insert is ultimately still only screwed into this same amount of total engagement, which is the limiting factor or weakest link, but by having a steal flange behind the hole it winds up making it at least twice as strong. these bolts need to be torqued pretty good, the stock bolts needed  a breaker bar and a floor jack just to break the damn things loose   now with the steel bushings I'm making from the lugnuts I should have no problem being able to tighten these bolts to 80-90 ftlb's of torque without worrying about aluminum threads at all, a thread insert is still only screwed into aluminum, and overall is only as strong as the next size up threaded aluminum hole could be.few pics in next post  tonight I machined the mounting boss down close to the required 12mm.Last edited by turbocad6; 05-21-2013 at 02:40 AM.miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:great work.regarding your earlier thought of serating the aluminum surface---that would have the opposite result from what you were trying to achieve as you would have less surface area in contact.miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:As far as threads go...Just as long as you have the same length of thread as the O.D. of the threaded part that's all you need..Longer threads are NOT any stronger and will never be.Example..1/2-13 threaded ROD..Once you get 1/2" DEEP threads...anything else is a moot point....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterAs far as threads go...Just as long as you have the same length of thread as the O.D. of the threaded part that's all you need..Longer threads are NOT any stronger and will never be.Example..1/2-13 threaded ROD..Once you get 1/2" DEEP threads...anything else is a moot point....zap!
Reply:Originally Posted by boatbuoyzap,that's pretty much true for steel but aluminum needs 2 to 3 times the diameter to get the same strength.