magnesium drilling

[chainsawjunky]

So while I was building my 044 I put the aftermarket elasto-start from Baileys on the one piece starter cover which is supposed to have the normal starter handle. The one piece starter handle has 4mm holes for the bolts to attach to the case. The two-piece(normal elasto-start cover) cover has 5mm holes. I went to the dealer to get bolts for it and he asked if I had the elasto-start and I said yes. So he gave me the 5mm bolts with me having no idea I had put the elasto-start on the wrong cover. My case has 5mm holes and my cover has 4mm holes. So should I go back and get the 4mm screws or should I drill the cover out to 5mm(13/64 if I can't find a metric drill bit)? Can I drill magnesium without screwing it up? The bolts were stocked so he has no problem with me taking them back and swapping for 4mm bolts. Any suggestions?

Evan

 

[ShoerFast]

Just a note to your question , as I don't know the parts fit that your looking for.

magnesium drills almost to easy, it is almost to soft and grainy and bits tend to want to take huge bites, have everything set up well, lube the bit with a light-oil or kerosene or diesel fuel and keep a consistent pressure, moderate speed.

The grabbness of magnesium makes it only slightly more of a trick then aluminum,,,,,,, IOW, 'NP'

 

[chainsawjunky]

Just a note to your question , as I don't know the parts fit that your looking for.

magnesium drills almost to easy, it is almost to soft and grainy and bits tend to want to take huge bites, have everything set up well, lube the bit with a light-oil or kerosene or diesel fuel and keep a consistent pressure, moderate speed.

The grabbness of magnesium makes it only slightly more of a trick then aluminum,,,,,,, IOW, 'NP'

IOW? NP? Is thread cutting oil ok, or should I use something else? And I've only drilled wood and steel before, any special techniques? Should I practice drilling on my cracked crankcase?

Evan

 

[blis]

IMO id get those 4mm bolts instead of drilling the case... alot more safer...

 

[chainsawjunky]

IMO id get those 4mm bolts instead of drilling the case... alot more safer...

But the case is drilled for 5mm bolts. Will the 4mm bolts fit in the case? I wouldn't be drilling the case. I'd be widening the holes that the bolts pass through to hold the rewind starter on.

Evan

 

[djmercer1]

non-ferrrous metals are typically easier to rill than steel as noted. in our shop we use dicated aluminum cutting fluid for these, but most any light oil or lard is suitable and we use high drill press speeds(1500 rpm).

as to the fit, it is possible that the bolts are used to align the parts, in that case the 5mm may ne necessary. also do you mean that the 5mm hole is threaded, if that is the case the 4mm bolt is useless and the part must be drilled. pics of the parts would be helpful.

 

[ShoerFast]

IOW? NP? Is thread cutting oil ok, or should I use something else? And I've only drilled wood and steel before, any special techniques? Should I practice drilling on my cracked crankcase?

Evan

Evan,

truth? spite or nothing would work, but any lube would help.

If you opt to run a practice hole, my bet is you will only drill one and will be impressed on how easy it drills.

 

[brian660]

dont push too hard especially with lubricant like kerosene or diesel, magnesium is flammable, kinda hard to light a chunk but the filings go up real quick in the right enviroment.




i`m serious

 

[blis]

But the case is drilled for 5mm bolts. Will the 4mm bolts fit in the case? I wouldn't be drilling the case. I'd be widening the holes that the bolts pass through to hold the rewind starter on.

Evan

ahh, should read more carefully :hmm3grin2orange:

if thats the case i see no problem, just get a sharp bit and decent fluid and drill press or something... High revs for magnesium i think...

 

[chainsawjunky]

non-ferrrous metals are typically easier to rill than steel as noted. in our shop we use dicated aluminum cutting fluid for these, but most any light oil or lard is suitable and we use high drill press speeds(1500 rpm).

as to the fit, it is possible that the bolts are used to align the parts, in that case the 5mm may ne necessary. also do you mean that the 5mm hole is threaded, if that is the case the 4mm bolt is useless and the part must be drilled. pics of the parts would be helpful.

Yes the 5mm is a threaded hole in the crankcase. And the cover has 4mm nonthreaded holes in it. I figured it would be useless. The serial number on my saw is x4xxxxxxx something like that. I just know 4 is a later model 044 and so my guess is that it came with the elasto-start and the cover that is drilled for 5mm bolts. Then I got the cover with 4mm holes without knowing about the change in size. Will thread cutting oil work as a lubricant?

Evan

 

[Rleonard]

I hear that a cutting torch works well (hehe!!)

Bob

 

[Crofter]

It is tricky to enlarge an existing hole. with no metal under the point the drill will likely chatter and make an oversize hole. Make sure you clamp down the cover as the drill may try to thread in and grab. Really what you should have is a reamer. You might try dulling the lips of the drill so it is more of a scraping action. Getting it to bite is not the problem.

 

[chainsawjunky]

It is tricky to enlarge an existing hole. with no metal under the point the drill will likely chatter and make an oversize hole. Make sure you clamp down the cover as the drill may try to thread in and grab. Really what you should have is a reamer. You might try dulling the lips of the drill so it is more of a scraping action. Getting it to bite is not the problem.

Think I should go 1/64 or 1/32 smaller? I'd like to not dull my drill bits but if I have to I guess I could.

Evan

 

[Urbicide]

You might try a Unibit #1. The #1 has 13 steps ranging from 1/8" to 1/2", in 1/32" increments. Your 5mm hole would fall in between 3/16" and7/32". Unibits are easy to use and won't grab on you like a twist drill bit can. opcorn:

 

[chainsawjunky]

That's a good idea but it's already done now. Drilled the 3 holes to 13/64 with no problems. Went to put it on and I realized the heads couldn't fit down in there on 2 of the holes. So I went back with a big bit and made a couple passes at it(the bit kept wanting to move instead of cut the metal) and then it fits on really nice. I tested the coil out by touching the sparkplug to the head. I was going to try and start it but I didn't have the right spark plug. I can get pictures of the cover if anyone wants them. And does magnesium rust? I'm thinking no, but I want to make sure since it's now unpainted metal where I had to drill to make the heads of the bolts fit.

Evan

 

[manual]

That's a good idea but it's already done now. Drilled the 3 holes to 13/64 with no problems. Went to put it on and I realized the heads couldn't fit down in there on 2 of the holes. So I went back with a big bit and made a couple passes at it(the bit kept wanting to move instead of cut the metal) and then it fits on really nice. I tested the coil out by touching the sparkplug to the head. I was going to try and start it but I didn't have the right spark plug. I can get pictures of the cover if anyone wants them. And does magnesium rust? I'm thinking no, but I want to make sure since it's now unpainted metal where I had to drill to make the heads of the bolts fit.

Evan

Magnesium does not rust, But will corrode. Do not use alodine as a anti corrosive treatment, A epoxy primer and then paint is recommend, to stop any exfoleation.
Do not breath any Magnesium dust, While sanding, grinding, or drilling.

 

[chainsawjunky]

Magnesium does not rust, But will corrode. Do not use alodine as a anti corrosive treatment, A epoxy primer and then paint is recommend, to stop any exfoleation.
Do not breath any Magnesium dust, While sanding, grinding, or drilling.

Do I just use any paint?

Evan

 

[manual]

Do I just use any paint?

Evan

Basically Yes, Seeing you are working on a stihl use the Stihl Paint.
What you are trying to do is protect it from the elements.

Just make sure you don't see any white powder on the surface.
Something like you would see on your car battery termnal ends.
If so just sand the area so it blends to the surface. and paint.

 

[Al Smith]

Mag will pretty much crumble when drilling.Aluminum has a tedency to come out in a big long curly cue .To slow down the "grabiness "in drilling either one,you can go a little towards negative on your drill sharpening.Also if you are drilling much aluminum,a chip breaker ground in the bit sure is better than having a big spring chase you around.

To enlarge those holes, a reamer,if you had one would have worked just dandy.