Screw removal using extractor bits ?

[greg_o]

Has anyone got experience with using a screw removal tool ?
I have a project bike (1972 CB350) with seriously stripped out oval head cross-point (Phillips) screws that retain a cast side cover plate on the crankcase. This cover is the only access to the oil filter, on this bike its internal to the engine. So removal is a must to change oil on the bike which hasn't really run in 20+ years. My concern is in drilling out the screws and using the extractor bits.
These screws are very frozen in place and not budging (hence the crosspoint stripping) so I'll likely get one good crack at this extraction method. Since the screws are oval/panhead they are flush to the cover and no tool can get to any edge.
So How do I use it best?  apply heat ?, penetrating oil ?, hammer....? How do I keep from shearing off the screws in the crankcase?

[TLRam1]

Yes, yes, yes...all the above. I would mix part transmission fluid with Acetone in a 50/50 mix. Use that as penetrating oil, put some on daily, tap with a hammer to loosen, apply heat also tap some more Than use a good extractor to remove.  I have had to drill them out before and it works okay.

These type of issues with a one-shot-deal you do all the above to increase your chances of success. I do have a set of extractors, where do you live, is the motor off the frame?

[TLRam1]

I see you live in Rockwall, any chance of bringing it to the wrench session?

[greg_o]

The motor is on the frame and the cover is very easy open access on the  lower right side crankcase.
Being on the frame provides more grip locations and leverage than if off so I thought Id leave it on

Yeah was thinking about bringin it to the wrench session, tossing it in back of the pickup and draggin it down.
The bike is old, kinda beat up and dirty. In short its a fair mess but a project to work on
I plan to clean it up slowly over time after I get the basics done.
I just cleaned and rebuilt the carbs. Drained the oil.
Need to :
    clean out the centrifugal internal oil filter,
     pop in a battery and re-fire it up
     run new fuel lines
     clean, drain, brake lines
     get new tube for front tire
    and on and on and on

[Magniac]

Good luck with getting the screws out. I would suggest before putting new screws back in, run a tap in the holes to clean up threads, and apply some anti-seize compound to the new screw threads. You don't want to go through this again in the future.

[lragan]

Good luck with getting the screws out. I would suggest before putting new screws back in, run a tap in the holes to clean up threads, and apply some anti-seize compound to the new screw threads. You don't want to go through this again in the future.

You are a braver man than I am.  It is really easy to get a tap in wrong and mess up the threads that are there.  I would just run a bolt in and out a few times with some penetrating oil, then flush out the hole (especially if it is a blind hole) before going back together with the whole assembly.

[Cannon]

I agree to all the above. My experience with bolt extractors is that they are prone to breakage when used in small diameters, such as i assume is the case here. In addition i would use alternative types of screws when putting it all together.Torx-bolts with "square" shaped heads, and maybe a little washer under it. Good Luck , and a happy new year too 

[Curtis_Valk]

Greg have you tried an impact driver (the kind with the cross-point tip that you whack with a hammer)?  Every motorcycle mechanic MUST have one.

Curtis

[Greg Cothern]

Well RATS!  I dont have one......  YET!  LoL, just an excuse for me to go buy one hehehehe.

[greg_o]

Greg have you tried an impact driver (the kind with the cross-point tip that you whack with a hammer)?  Every motorcycle mechanic MUST have one.

Curtis

Yep. unfortunately the impact wrench is what finally stripped out the heads of the screws.
The cross points were marginal to start with... I heated up screws and case with a heat gun and whacked the screws with the impact wrench, slowly at first then with more force as the screws are pretty well frozen. All I accomplished was to round out the screw heads.
Now I'm on the slippery slope...wondering if I should leave well enough alone or plow forward and drill and apply screw extractors. My concern is that the extractor bits (hardened metal) are brittle and if I snap one off then I'm truly    ahem    screwed.
The only reason to get to the internal oil filter is the bike has been sitting for > 20 years and when I finally got the drain plug off (it was stuck too) there were plastic debris in the bottom of the plug indicating some FOD is in the engine. BTW the oil drain plug was so frozen on,  that I had to apply a cheater bar and the resultant torque twisted the wrench adapter boss apprx 15 degrees around. Its a project....   

[Curtis_Valk]

You have correctly assessed the situation.  The screw extractors are a gamble.  If they work, great.  If one breaks off you are truly screwed.  Try drilling out a hardened tool from steel with aluminum surrounding.  Guess where the bit is going to go?  I'm close by if you need moral support.  Give me a call if you need to.

Curtis

[Charles S Otwell]

If the screw is on a flat surface you can lay a flat washer over the head of the screw and weld it to the screw then weld a small nut to the washer let cool a little then gently work back and forth till it turns loose. Worse case is the head breakes off and your back to drilling.

[Smoked U]

Try investing in some left hand twist drill bits for this job. Use a good center punch to get things started in the right area.

I have been surprised by the fasteners that have simply twisted out of a frozen hole once the internal pressure is released by some drilling and subsequent heat generated by the drilling process.

Again, try to get some penetrating oil in the works first. Heat the area up good and shoot a penetrating agent on the culprit. It will tend to suck some of the penetrant into the threads as it cools the hot metal.

If none of this works, you still have the hole to use the screw extractor as a last resort.

Mess up the threads (they may come out with the fastener, hello electrolysis)? That's why they sell helicoils.

Best Wishes.

[dgc67]

If the screw is on a flat surface you can lay a flat washer over the head of the screw and weld it to the screw then weld a small nut to the washer let cool a little then gently work back and forth till it turns loose.

Cool idea...

simply twisted out of a frozen hole once the internal pressure is released by some drilling and subsequent heat generated by the drilling process

I concur with this as well.  I have carefully drilled a hole in the center of a screw and then used a chisel punch (?name) and hammer to tap it around and loose (with plenty of penetrating oil of course).
Also have used Helicoils and they worked well.

[greg_o]

If the screw is on a flat surface you can lay a flat washer over the head of the screw and weld it to the screw then weld a small nut to the washer let cool a little then gently work back and forth till it turns loose. Worse case is the head breaks off and your back to drilling.

Sounds great, unfortunately this problem is pan head screws in countersunk holes in the cover.

Thanks for the help guys
I think I'm gonna heat soak the screws multiple times and drill out the centers and see what happens.