Clarkson Radius Grinding Fixture

Hi Steve,

No it is fairly straight forward other than it has an adjusting dovetail slide to bring the tool forwards (sideways movement is accomplished by the cross travel screw). I have only used it a couple of times and that was for a shaper tool grind. However it did produce an excellent radius - far better than a hand formed one!

As I said previously I have to dig it out and currently Mrs Rag is, much to my frustration, limiting my 'shed time'; something to do with the time of year, I will drag it out and photograph for you.

Noel, interesting that you say the bore of the toolholder is 1.25" and not 1.5" - mine is 1.500" and is sleeved with a steel sleeve. There is then a further holder (long) shown in photo #2 of the second 24/12/2020 post. this screws into the rear of the holder and is then sleeved down to either 1.25" or by reversing is sleeved down to 1.000".

Phil, I would certainly appreciate a copy of the MkII instructions as I have never seen/read any and have so far used it 'intuitively' (and more than likely wrongly!). Can I PM you as well?

I just checked mine earlier this evening and it is definitely 1.5" bore. It looks to be original but I suppose someone could have bored out before I got it.

Phil

Phil I am a bit late coming to this discussion due to Christmas jobs for her who must be obeyed. Regarding your sketches you are correct that winding the table nearer the wheel reduces the radius. The correct way to use the radius grinding attachment is to set the tool as in your initial setup illustration and then touch the end of the tool onto the grinding wheel. The table is then locked and the tool is advanced into the wheel by using the threaded sleeve that fits into the aluminium block. The cutter to be ground is held in a standard holder with a collar in front and behind the ally block / sleeve assembly so the tool can be rotated. A finger is mounted in the usual fashion to locate and index the cutter.

Having got my RGA out and studied all that has been said, here Baz is right ! I could not understand the Bore in the alli housing being 1.5" when most clarkson gear revolves around 1.25" or less. BUT with the 1.5" to 1.25" sleeve threaded and grubscrewed to the alli body it is the feed screw, and the pivot point remains centre. The way I see it there is a 1.5"od sleeve about 3" long with an internal thread may be 20 tpi X 1.375" for 1/2" and a Knurled ring od 2" X 1" long stepped down and threaded 20tpi X1.375". This ring will have a 3/8"whit grubscrew in the center of the knurling . Then there's the Alli holder Bored 1.5".

The delux version could have a graduated ring at 50 thou per full turn.

Like most clarkson manuals the instructions are at best brief and very little in the way of clues as to what is IF you have parts missing as is so often the case.

WELL, at least I think I know what I'm doing NOW ! IF any one needs a copy of the drivers hand book for the Mk 2 RGA let me know ! Noel.

Clarkson instructions are very vague, they seem to assume everyone using the equipment is a professional cutter grinder and just needs a simple drawing of what goes where. The instructions for the basic machine at least include a list of standard parts so you know what you have and what you are missing but the radius attachment and drill grinding attachment booklets don’t, so as Noel says you may have an important part missing and not know about it.

Noel, I will photograph my threaded sleeve tomorrow and mail it to you.

Baz

Could I trouble you for a copy of the sleeve picture too?

I'm almost done with my reproduction spindle holder, and spindles seem like the next step.....

If anyone has a definitive picture of what the RGA 'set' contained, that would be very helpful.

As an side, I assume all of this missing part nonsense is due to Clarkson making a box which didn’t allow storage of an assembled unit?

Ian

Ian, Your right about the box ! The only good thing is I can make a box for my drill grinder attachment which is complete that will hold it assembled . The real problem is that if you have many attachments they will usually share parts . As to the RGA there were several kits. Mk2, 97111 was the basic set Imp 97113 same but metric. This was the basic set up, the tooth rests you made to suit your job and the bushes came from the machine set. and it had a 1"dia centre for setting up. The delux set was 97112 or 97114 Imp or metric. This had a raising block about 2" thick to raise the tool holder so that side and face cutters could be done and a S&F regrind mandrel which was 91120 Imp or 91121 metric. The raising block replicated the top of the swan neck and the underside of the tool holder - just 2" thick and a single central hole.

Most drawings or pictures show the wheel mounted on a spindle extension, needless to say this is not in the kit it's an extra that should come with Mk 2 grinders but NOT the Mk1 it's Pt No92614

I'm not very good as a draftsman but dimensioned sketches could be done of most of the parts used on these machines if required, I have most of them. Goodnight and God bless, Noel.

Ian Armstrong, you have a PM.