hairyaardvark Posted March 6, 2017 Share Posted March 6, 2017 Hello. I need to obtain some replacement wheel struts. Have tried chrome moly but it is not strong enough. Any ideas on what the original material (maybe spring steel) and where to get it? Thank you Richard Link to comment Share on other sites More sharing options...
Head in the clouds Posted March 7, 2017 Share Posted March 7, 2017 The originals are 4130 Chromoly but they have to be heat treated after you cut and drill them. I can't remember the sizes but you can measure that off the originals of course - off the top of my head I think the outer was 1.5" diameter x 0.120" wall and the half length internal sleeve was 1.25" x 0.095" wall but don't take my word for it ... Your avatar doesn't say where you're located so I can't recommend a heat treatment plant but you need to be sure they know what they're doing with the tempering process otherwise they could end up brittle. You'll also probably need someone with a 20-50 tonne shop press to straighten them after heat treatment, they often end up with a fair curve in them. Don't try and do it with a sledge hammer or it'll probably spring back and kill you. Likewise in the shop press they need to be fully contained so that if they slip out from under the ram they don't go anywhere at high speed. Seriously - it can be deadly, to straighten even a slight curve you need to bend it like a banana in the opposite direction. I drilled holes right through my shop press vertical main supports and threaded the legs through them so they were positively held under the ram that way and couldn't escape. Link to comment Share on other sites More sharing options...
facthunter Posted March 7, 2017 Share Posted March 7, 2017 In the heat treated condition (tempered) they are used in they will bend and stay bent, if you hit the ground hard enough. If you can hold them you can straighten them and as said you go way past straight to make it end up straight. It would not be impossible to make some apparatus that does in situ, MAYBE.... but you shouldn't subject the fuselage to much load in the process.. I think most of the bending of the leg happens near the top (as you would expect). Any good shop that hardens and tempers springs should be able to do the heat treatment. Most spring resetting is done at temper heat (not above) or it just bends too easily. I reckon you would get away with doing it cold (ambient) in a lot of situations Nev Link to comment Share on other sites More sharing options...
M61A1 Posted March 7, 2017 Share Posted March 7, 2017 Hello. I need to obtain some replacement wheel struts. Have tried chrome moly but it is not strong enough. Any ideas on what the original material (maybe spring steel) and where to get it?Thank you Richard Get hold of Glen Shaw at Dalby Air Maintenance. They are sleeved Heat treated 4130. Link to comment Share on other sites More sharing options...
boleropilot Posted March 21, 2017 Share Posted March 21, 2017 g'day Richard, don't forget there is a shorter, smaller diameter inner section that is located inside part of the outer struts - also, the bolt holes at each end are different diameter I've been told they have to be perfect in relation to strength and flexibility - too brittle and they snap, too soft and they bend... I bought a newly manufactured set a while ago (can't remember who from but they were as expensive as hell) because those on my 3,500 hour Drifter were buggered I watched the late great Wayne Fisher straighten the original ones in a hydraulic press - wow, had 'em straight in a flash - and he had the tailfeathers off the aircraft in about 10 minutes! the big fun starts when it's time to re-install them into the aircraft - those little washers just love to fall inside the aircraft - make sure you have a magnet on the end of a telescopic thingo (get one with a little mirror) let me know if you need the details of where I got my new ones from, but be prepared to sell a kidney to pay for them... BP Link to comment Share on other sites More sharing options...
Head in the clouds Posted March 21, 2017 Share Posted March 21, 2017 ... but be prepared to sell a kidney to pay for them... I hope you didn't get badly ripped off because if you can cut and drill them yourself it's not a very expensive exercise to make them up. Current price for 1.5"x 0.0120" 4130N from Bralco (formerly Airport Metals) is $11/ft, 1.375" x 0.0120" is $13/ft, can't recall which size you need for the outer but you need about 8ft of the outer and about 4ft of the inner sleeve in total. The inner sleeve material (1.250" or 1.125" x 0.095") is $9/ft or $7.50/ft, so the most the material can cost is $140. The freight would be about $30. Cut and drill it yourself using the old ones as examples and then the heat treatment is about $60 as long as you are happy to wait for a day or two until the heat treatment people have enough for their oven. So - add GST and you wouldn't get me selling a kidney for $250. Link to comment Share on other sites More sharing options...
M61A1 Posted March 21, 2017 Share Posted March 21, 2017 Hey HITC, the heat treating was the biggest problem for the guys at DAM. They found someone to do it, that claimed to have the correct setup, and very quickly found that it was inadequate and had to be retreated. Unfortunately that involved sending a batch to Melbourne. The first lot were soft, I put them on the hardness tester at work and they didn't even make the RW 'C'' scale, so they were about as hard as annealed 4130. Believe it or not apparently the biggest issue (and I did a lot of phoning myself) is getting a kiln big enough to hang a 4 ft length inside. You don't want them laying down, they bow too much. Still DAM's price was quite reasonable.... I think I paid about $470 for a pair. Link to comment Share on other sites More sharing options...
sandman Posted March 21, 2017 Share Posted March 21, 2017 Dalby Air Maint. are good for the drifters, I believe they have a few spare struts to. Link to comment Share on other sites More sharing options...
boleropilot Posted March 21, 2017 Share Posted March 21, 2017 I recall I paid about $600 for mine....including freight from Victoria. let's hope they are as good as advertised... BP Link to comment Share on other sites More sharing options...
Head in the clouds Posted March 21, 2017 Share Posted March 21, 2017 Hey HITC, the heat treating was the biggest problem for the guys at DAM. They found someone to do it, that claimed to have the correct setup, and very quickly found that it was inadequate and had to be retreated. Unfortunately that involved sending a batch to Melbourne.The first lot were soft, I put them on the hardness tester at work and they didn't even make the RW 'C'' scale, so they were about as hard as annealed 4130. Believe it or not apparently the biggest issue (and I did a lot of phoning myself) is getting a kiln big enough to hang a 4 ft length inside. You don't want them laying down, they bow too much. Still DAM's price was quite reasonable.... I think I paid about $470 for a pair. Yes OK, always respect everything you say M61A1, as I'm sure you know, but it doesn't have to be quite that difficult ... With even greater respect I do have to say that whether the item is bowed or not after heat treatment has nothing to do with whether it was hung or laid in the kiln providing that it's soaked at temperature for several hours, it will be evenly heated overall. However it does have all to do with how it enters the quenching fluid. As you'd be aware it can be quenched in water (not recommended) oil, or a variety of gels or salts. The gels are the kindest but are specialty work not generally available here, so oil is the most likely, given that's how the local industry does spring hardening and tempering. If the items ended up too soft it wouldn't/shouldn't have had anything to do with the hardening process, more likely someone doesn't have good control over the tempering which is much more difficult to get right, and 'amateur' shops err on the side of over-tempering because people tend to complain if their springs are brittle and break but generally have little to say if they're a bit soft and relax a little later. Consequently a customer should ideally have their own hardness testing equipment, or know someone who does. It's not expensive stuff, my Brinell cost about $250 or so and I would just charge for my time if someone wanted to confirm their heat treatment. Getting back to the bowing of the item, from experience I do think it's almost unavoidable with anything less than a direct vertical drop into a deep oil or gel quenching bath, since one side of the item will always hit the fluid first and contract earlier than the other side. There's nothing wrong with banana shaped properly heat treated items, you just need to have the right straightening equipment - a shop press with a setup for full escape containment of the rod/tube and a dial gauge. There are two or three highly knowledgeable and capable heat treaters in Brisbane which I could recommend and who will provide a finished product within 5% of requested hardness after tempering, but as I mentioned in an earlier post I don't know where the OP is, and he/she hasn't responded to that, so there's not much point in making recommendations if they're in Adelaide or Perth, for example ... Link to comment Share on other sites More sharing options...
Head in the clouds Posted March 21, 2017 Share Posted March 21, 2017 I recall I paid about $600 for mine....including freight from Victoria.let's hope they are as good as advertised... BP Hellsbells - that's pretty fair, if the basic cost of materials and processing is $250 as I demonstrated - and you want someone else to do all the precision cutting and drilling on your behalf, warranty that it fits your plane, pack and send it, well at my modest charge out you'd think I have to do all that for less than $75/hr? Oh - and I pay the freight ... So you have a kidney for sale for $600? I'll take it! Link to comment Share on other sites More sharing options...
M61A1 Posted March 21, 2017 Share Posted March 21, 2017 Yes OK, always respect everything you say M61A1, as I'm sure you know, but it doesn't have to be quite that difficult ...With even greater respect I do have to say that whether the item is bowed or not after heat treatment has nothing to do with whether it was hung or laid in the kiln providing that it's soaked at temperature for several hours, it will be evenly heated overall. However it does have all to do with how it enters the quenching fluid. As you'd be aware it can be quenched in water (not recommended) oil, or a variety of gels or salts. The gels are the kindest but are specialty work not generally available here, so oil is the most likely, given that's how the local industry does spring hardening and tempering. If the items ended up too soft it wouldn't/shouldn't have had anything to do with the hardening process, more likely someone doesn't have good control over the tempering which is much more difficult to get right, and 'amateur' shops err on the side of over-tempering because people tend to complain if their springs are brittle and break but generally have little to say if they're a bit soft and relax a little later. Consequently a customer should ideally have their own hardness testing equipment, or know someone who does. It's not expensive stuff, my Brinell cost about $250 or so and I would just charge for my time if someone wanted to confirm their heat treatment. Getting back to the bowing of the item, from experience I do think it's almost unavoidable with anything less than a direct vertical drop into a deep oil or gel quenching bath, since one side of the item will always hit the fluid first and contract earlier than the other side. There's nothing wrong with banana shaped properly heat treated items, you just need to have the right straightening equipment - a shop press with a setup for full escape containment of the rod/tube and a dial gauge. There are two or three highly knowledgeable and capable heat treaters in Brisbane which I could recommend and who will provide a finished product within 5% of requested hardness after tempering, but as I mentioned in an earlier post I don't know where the OP is, and he/she hasn't responded to that, so there's not much point in making recommendations if they're in Adelaide or Perth, for example ... I'm quite sure Glen would love to know a good facility in Brisbane.. Link to comment Share on other sites More sharing options...
Head in the clouds Posted March 21, 2017 Share Posted March 21, 2017 I'm quite sure Glen would love to know a good facility in Brisbane.. OK, I'll PM you tomorrow. Link to comment Share on other sites More sharing options...
Head in the clouds Posted March 21, 2017 Share Posted March 21, 2017 I'm quite sure Glen would love to know a good facility in Brisbane.. I'll post it here rather than PM, others may benefit from the info too. It looks like heat treatment is in something of a decline. As far as I can tell Thermalhire at Geebung is no more but perhaps they've merged with Heat Tech which was over the road in Granite St. It's a very long time since I had anything to do with them but they did a good job at the time. Heat Treatment Australia is at Coopers Plains and they have aerospace experience and AS9100 accreditation. They're a big operation and were quite expensive for a couple of small items, but did good work. Queensland Heat Treatment, WYAMPA and Metal Components Australia all appear to have merged and are at 49 Dunn St, Rocklea. MCA did the gear legs for my AussieMozzie build and they did a good and accurate job of the harden and temper but the legs required a lot of straightening in the press afterwards. They also did the CRMO sheet metal components for the wing attachments where it was important to get them in the right final hardness/temper state, which they did well. Five gear legs and about 20 small plates only cost about $100 and the wait time for a full oven was about 3-4 days. Link to comment Share on other sites More sharing options...
boleropilot Posted March 21, 2017 Share Posted March 21, 2017 Looking forward to your final comments on this HITC. quick question, I had my u/c legs powder coated - would that affect them in any way or prevent them from being tested with your Brinell? btw, is there something else I can call ya apart from hitc? heady? headclouds? foggy? doomawdriver? or something like - maybe - Bill? Link to comment Share on other sites More sharing options...
Head in the clouds Posted March 21, 2017 Share Posted March 21, 2017 is there something else I can call ya apart from hitc? Just don't call me late for dinner ... .... quick question, I had my u/c legs powder coated - would that affect them in any way or prevent them from being tested with your Brinell? Powdercoating cure temperature is about 200°C and tempering temperature is above that so it shouldn't affect the heat treated condition. The hardness tester uses a small ball impacted onto the surface of the steel and then you measure the size of the indentation with a magnifier and tiny scale, it's a very simple test, but reasonably accurate. You'd have to remove the powdercoating from the test area. Frankly I wouldn't bother unless you're bending the gear legs easily. I'll try and attach a *.pdf file from the University of Vermont, it tells you pretty much everything you need to know about 4130 Chromoly heat treatment - OK, it's too large, it's 660Kb, anyone who's interested can send me their email address via PM if you like, and I'll email it to you. Link to comment Share on other sites More sharing options...
boleropilot Posted March 21, 2017 Share Posted March 21, 2017 I'll just try Alan, that should work...and work on my landings! BP (Dave) Link to comment Share on other sites More sharing options...
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