Seating a non Bedrock frog

[dunbarhamlin]

Hi folks

Have started bringing a Record T5 back into service, and wondered about seating the frog.

I am only used to bedrock style frogs (a breeze) and given the small footprint between body and frog, want to improve the contact (the original maching is poor.)

Think I've heard of valve grinding paste being used? Not a petrol head, so no idea about this.

Any suggestions buch appreciated

Cheers
Steve

[fingers55]

Steve - if you cut of a piece of 8 or 10mm dowel squarely it can then be put into the pillar drill. Dip the end into some valve grinding paste and you can then use it to clean up the areas of the casting where the frog seats by just moving it around underneath the rotating dowel...worked for me - Rob

[dunbarhamlin]

Oo, thanks Rob, will give it a go. Guess I can get valve grinding paste from the likes of Halfords?

Steve

[fingers55]

Steve - Halfords would be a good place to have a look I would have thought. You can sometimes buy a double ended tin with coarse in one end and fine in the other. Fine is what I used, coarse will really chew off the metal - Rob

[dunbarhamlin]

Thanks again, Rob.
This one won't be up to your standards, but if I can get it to perform that'll suit.
Happily japanning is all but complete and iron, stay set and lever cap are good.
Cheers

[engineerone]

you could of course be all grown up and engineering about it

as dc has stated elsewhere, one can use a proper scraper to flatten the surfaces. you could make one out of an old chisel, a three sided one is best, so actually you could grind down an old file as well.

a marker pen also is quite useful for marking out.

paul

[dunbarhamlin]

Hi Paul
What's the m.o. for this approach? Presume blue/permanent marker, rub together, scrape the shiny spots, repeat?
How do you prepare a scraper? Just square off the end of file to give three sharp edges? What technique do you use with the scraper (scratching away with a corner, pushing/pulling the edge at high/low angle?)

Sorry for the dumb Qs - no metal working experience - just means more fun stuff to learn.

Thanks
Steve

[david charlesworth]

Steve,

Its in my first book. A flat engineers scraper is better, 6"file, slightly curved radiused end, square cutting edge from grinder, though the flat faces are usually slightly concave from the surface of a bench grinder. Tormek is ideal.

Whatever. The drill press and valve grinding may work as well but does not deal with irregularitied on frog casting.

Sole casting machining is usually worse.

When you get close the loose grit from APTC sold to use on the metal japanese flattening plate can be used with a little water or oil. If you rub the two castings together it is possible to get 90% or even 100% contact.

Dvaid

[engineerone]

steve,

a lot depends on whether you have any grinding equipment.

if you have a high speed type grinder, say an old black and decker, rather than a tormek, then you just have to be careful.

find a couple of old files and practice. the important thing is not to reduce the temper etc. you want to ensure that they have handles. then clean off the teeth toward the end. make it smooth, do this by rubbing on the wheel, and dipping in water a lot. once you cannot really see the teeth pattern, you can start on the scraping part. as david says, just square the edge, and create a kind of blade, does not need to be anywhere as acute as plane. aim for about 50 degrees i think.

the only reason for removing the teeth is to make the scraper nicer to use, since if you hold the blade near to the edge, the
teeth will rub you fingers badly

if you can and have sharpened your plane and chisel blades, then you can make a simple scraper. in the model railway world, people use things like swiss files and even hack saw blades to make scrapers. they are generally used to remove solder, but the same principle applies. what you need is a strong cutting edge, so a greater rather than a lesser angle is required.

hope that helps

paul

[dunbarhamlin]

Thanks David
I had read through that (several times ) yesterday but being unfamiliar with the tool had given me pause.

I had contemplated making a simple cradle for the frog, so it could be treated the same way on the pillar drill

Thanks for the detail, Paul - helps a lot.
Suppose I will have to bite the bullet and get an electric grinder.

Cheers
Steve

[engineerone]

well you could always be like alf, colin and me and also have a hand driven one, the mole was pretty good ;D

paul

[dunbarhamlin]

Certainly sounds more my style - I did recently encumber my brother with tailed drill, circular saw and drill press in preference for braces, rip saws and pillar drill.
Now I just need to move somewhere with a water wheel so I can unplug the bandsaw...

[davidc]

Hand cranked grinders can work very well.

Surely you might know someone with electric grinder? It is not always necessary to own tools.

What about local turning club?

Just ideas.
David

[petemaddex]

Hi,
I use the grinding past and rubbing technique, if you have no past just soak some sandpaper.

Pete