Might anyone be able to help with a snapped bolt?
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Just to add, the Marzocchi forks I have taken apart all had really good threadlock on the bolts, which may be hampering your removal efforts. I don't know if there is a way to melt the threadlock first before you try undoing it?
integerspin
Senior Retro Guru
I can usually remove bolts and not damage threads, I can always helicoil it if need be.
Drilling a hole, if I can't do it on the milling machine, is a lot easier with a small air drill. You start with a very small drill and you can correct the location with a centre punch, you just chip the side of the hole away to move the drill over. The larger the hole gets the less you can correct it's position.
If you going to buy stud extractors[easy outs] the best ones are fluted rather than the spiral left hand thread. The spiral ones work some times but I often find they split the bolt and make it harder to get out, the fluted ones you hammer into the bolt, after drilling a hole, they work more often than the others for me.
If it's likely to be loose sharpen a drill to cut backwards[I know it won't cut very well] then try drilling it out, sometimes fasteners unscrew.
Another very good method is chemical, steel bolts in ali can be burned out in sulphuric acid[battery acid] it leaves the threads lovely and clean[anodised]
I have a gearbox case here that has a snapped stud and someone has drilled off centre. I am going to try soaking it in Alum, it's available in Tecos, can't remember what it's for. I am told a warm solution of Alum dissolves steel, but doesn't do anything to ali?
Drilling a hole, if I can't do it on the milling machine, is a lot easier with a small air drill. You start with a very small drill and you can correct the location with a centre punch, you just chip the side of the hole away to move the drill over. The larger the hole gets the less you can correct it's position.
If you going to buy stud extractors[easy outs] the best ones are fluted rather than the spiral left hand thread. The spiral ones work some times but I often find they split the bolt and make it harder to get out, the fluted ones you hammer into the bolt, after drilling a hole, they work more often than the others for me.
If it's likely to be loose sharpen a drill to cut backwards[I know it won't cut very well] then try drilling it out, sometimes fasteners unscrew.
Another very good method is chemical, steel bolts in ali can be burned out in sulphuric acid[battery acid] it leaves the threads lovely and clean[anodised]
I have a gearbox case here that has a snapped stud and someone has drilled off centre. I am going to try soaking it in Alum, it's available in Tecos, can't remember what it's for. I am told a warm solution of Alum dissolves steel, but doesn't do anything to ali?
Also.If theres a bit sticking out then have you tried tightly locking a pair of mole grips onto the stump and attempting to turn that :?
NOTE- To everyone
Not everyone has a milling machine or pillar drill or any fixed engineering machine.Most will have a drill and the ability to buy a drill bit of the correct diameter
The pound shop and the like has little kits of 3-5 different sizes of screw extractor.
Drill a hole if you can in near enough the centre of the stuck bolt.
Chances are you dont own a hardened centre punch so use a wood nail though a masonry nail is better because that is hardened.
Drill about 5mm into the top and then attempt to screw in the extractor.Ive found that they bite in quite quickly and because its a reverse thread the harder you force it in the better as this also forces it to undo.
Ive taken out bolts at the bike station that have been rusted in for a good 30 years[judge from the age of the bikes]
If you own a drill then your outlay should be no more than a fiver for the drill bit and extractor kit
Still waiting to hear which model they are though :?
NOTE- To everyone
Not everyone has a milling machine or pillar drill or any fixed engineering machine.Most will have a drill and the ability to buy a drill bit of the correct diameter
The pound shop and the like has little kits of 3-5 different sizes of screw extractor.
Drill a hole if you can in near enough the centre of the stuck bolt.
Chances are you dont own a hardened centre punch so use a wood nail though a masonry nail is better because that is hardened.
Drill about 5mm into the top and then attempt to screw in the extractor.Ive found that they bite in quite quickly and because its a reverse thread the harder you force it in the better as this also forces it to undo.
Ive taken out bolts at the bike station that have been rusted in for a good 30 years[judge from the age of the bikes]
If you own a drill then your outlay should be no more than a fiver for the drill bit and extractor kit
Still waiting to hear which model they are though :?
integerspin
Senior Retro Guru
dyna-ti":1s5izuq9 said:NOTE- To everyone
Not everyone has a milling machine
They will have to figure a way to do it in the lathe then;-)
If you get stuck and do want to post it to someone let me know..
Most effective for me is inert gas welding and melding a bigger hexagon head screw on it.
I often tried drilling holes, using special bits, threading bits, turn-out-srews ... etc.
But with a welding machine it makes real fun ;-)
Last Devember I fixed most of my forks with problem screws (broken, rounded etc.) in some hours ;-)
Only 2 M4 where difficult, because they have been cut off inside the hole and I had to cut the brake booster to reach them ;-)
I often tried drilling holes, using special bits, threading bits, turn-out-srews ... etc.
But with a welding machine it makes real fun ;-)
Last Devember I fixed most of my forks with problem screws (broken, rounded etc.) in some hours ;-)
Only 2 M4 where difficult, because they have been cut off inside the hole and I had to cut the brake booster to reach them ;-)
