Drilling and tapping a tappet cover stud hole.

[Splodge]

Hi
I need to drill out, tap and fit an insert into one of the studs holes on my Right hand inlet tappet cover.

I wondered if anyone has any tips or tricks for avoiding getting swarf into the engine.
Thanks

 

[bosco659]

I‘m not certain but isn't the stud hole a blind hole? If thats the case if you plug the tappet cavity with a rag, chips shouldn’t get in there. When drilling or tapping, coat the tools with grease to catch the chips and clean often. You can also keep a strong vacuum cleaner hose near the hole you’re working on.

 

[5twins]

The one I had to fix was a blind hole. You may need the special bottoming tap so the hole can be threaded deep enough to accept the insert.

 

[Splodge]

Arr.. yes you are correct, I went and had a poke in the hole with a screwdriver and well I never it is a blind hole, as long as I don't drill too far in I should be fine.

It has been like this ever since I bought the bike, 'Slight oil leak' has been an advisory on every MOT so it's about time I did something about it.

The hole was already badly drilled out to 8mm and stripped so I have got to go up to 10mm, which is why I've been avoiding the job.

I've 3D printed a drill guide which should help.

 

[Adamc]

Arr.. yes you are correct, I went and had a poke in the hole with a screwdriver and well I never it is a blind hole, as long as I don't drill too far in I should be fine.

It has been like this ever since I bought the bike, 'Slight oil leak' has been an advisory on every MOT so it's about time I did something about it.

The hole was already badly drilled out to 8mm and stripped so I have got to go up to 10mm, which is why I've been avoiding the job.

I've 3D printed a drill guide which should help.

Ther will not be much meat on the flange after drilling so go easy with the insert and when tightening down on the cover screw.

 

[bosco659]

I like that drill guide!

 

[Splodge]

I like that drill guide!

If it works out ok I'll make the stl. files available, I'll find out the drill size needed
for a standard Helicoil and make a drill guide file for that too.

I ordered a bottom tap which arrived today, here is a picture of the kit I'm going to use.
I have re-printed the drill guide with the hole to be drilled moved inwards by 1mm, which
will hopefully help a bit.
The blue one is a tap guide.

I'm going to be using an EZ-LOK insert, it seemed to be the best thing to use in the circumstances, I am
thinking of shortening it by a millimeter or so though so I don't have to drill so deep, any
thoughts on that would be appreciated.

I have also now printed a drill stop coller so I can accurately set my drilling depth.
I've used taps and dies a few times but I'm by no means an expert at this stuff, I'm pretty
nervous about it.
Neil

 

[RustiePyles]

I used a liberal amount of grease on both my tap and drill bit. The grease will catch the swarf. A rag stuffed into the access hole will catch the rest.