Hi, take look at my post “ Engines Woes “ on the Lanchester Forum.
I replaced a Core Plug only yesterday in my Lanchester Cylinder Head, and also “Repaired” coroded water way holes using Loctite Aluminium Putty .

Cheers Al

PLEASE DO NOT USE tjt77s method of hitting two hammers together. It is highly dangerous as the hammers can shatter causing serious injury.

re the theory of shattering hammers.. Im unsure where this long held old wives tale comes from, but it has stuck for decades.. Ive never experienced this issue and have been whacking hammers agin each other for over 40 yrs.. especially for installing for plugs.. whilst its contrary to long standing engineering practice, a good quality ball pain hammer, hit on the ball end with a larger hammer, is the ideal tool for expanding core plugs in my opinion.. Ive broken lots of hammer handles in my life..but NEVER suffered any damage to the business end..which is commonly made of the same steel that ANVILS are fabricated form.. although if you can find a really cheap cast iron hammer (such as in those really nasty budget Asian body hammer sets sold online) theoretically it is possible ..

re the theory of shattering hammers. It is just good practice to make people aware when you don’t know there abilities or there equipment. Not me but journeymen I trained under passed on an experience. I wouldn’t dream of calling them old wives. The male end of a half inch square drive socket extension with a slightly domed end can work quite well if you are not too worried about abuse to it. I suppose you could dome a suitable size punch.

First rule of engineering, if it's hard hit it with a softer tool, if you wish to distort it hit it with a harder tool, Core plug soft, hammer OK, hammer on hammer, both hard not OK, the only time you use hard on hard is if you wish to break something (ie a seized bearing on a shaft) in that case take precautions.

tjt77 wrote: ↑Tue Dec 11, 2018 5:43 pm re the theory of shattering hammers.. Im unsure where this long held old wives tale comes from, but it has stuck for decades.. Ive never experienced this issue and have been whacking hammers agin each other for over 40 yrs.

Well, you have been kucky then . Long may your luck continue . It is certainly not an old wives tale that hardened metal is liaible to shatter if struck with similarly hardened metal

Id agree that is best to use caution ..many different tools can be used to expand for plugs.. I think the critical thing is to size the tool that is used to expand the plug needs too be minimally 1/2 the diameter of the plug.. if one uses one too small to will leave a depression without fully expanding the plug.. and yes a 1/2 drive socket bar will work on the smaller ones.. 3/4 drive can be used on larger ones.. a suitable brass or copper faced hammer is best against a hard steel tool.. such as the copper faced hammer for tightening the big nut on spoke wheels.. I'll stick to my 2 hammer method as I have it 'down pat' as they say ..one whack does the trick.