I want to make a radius jig on a router table

[hawkeyefxr]

I have got back into making Solitaire boards. Previously i have mounted them on a sheet of 10mm ply and clamped it to the router table with a centre point so the board rotates, the problem is that this restricts the cut vertical movement which means i have to take two bites at machining a round.

What i have thought of doing is using a short length of 6mm*20mm bar, the router table will be machined to accept the so it slide giving me adjustment to use different diameter boards. A 6mm dia bar threaded at the end so that it screws into the square bar from the underside. The problem is this could weaken my router table top.

My router table is home made and i have had it for many years and for me is perfect (except for the radius cut lol) It's thickness is 1 1/4".

This is in my head so have no drawings .

Has anyone done something like this, anyone have a better idea, any ideas really

Cheers

 

[Steve Maskery]

Have I got this right, you are trying to make disks on the RT?
If so, I have an excellent jig. I wish I could claim to have designed it, but I didn't. I can't remember the name of the guy who did. But it is excellent, it really is. It runs in a mitre slot, but if you don't have a mitre slot you can run it against the edge of your table. It is infinitely variable from as small as you can handle to, well, how much stability have you got?
I'll take some pics tomorrow.

 

[Yojevol]

Without some pics I don't quite understand your present method, particularly the restriction of vertical cut movement. However, that aside, I would think you have trouble in getting a clean cut as for half of the revolution of the blank you will be cutting 'uphill' against the grain thus risking tearout. The way round this is to turn the blank over every 90 degrees of its rotation so the cutter is always cutting 'downhill'.
I have been doing something similar to this in recent times in producing gear blanks for my clock making activities. For this I've used my disc sander. As with your system, I clamp a sheet of ply to the sander table. I have a vertical brass rod mounted in the ply to take the roughly cut gear blank. I then adjust the position of the ply sheet such that the sanding disc is just biting into the blank. Rotating the blank produces a nice clean disc.
Brian

 

[hawkeyefxr]

Have I got this right, you are trying to make disks on the RT?
If so, I have an excellent jig. I wish I could claim to have designed it, but I didn't. I can't remember the name of the guy who did. But it is excellent, it really is. It runs in a mitre slot, but if you don't have a mitre slot you can run it against the edge of your table. It is infinitely variable from as small as you can handle to, well, how much stability have you got?
I'll take some pics tomorrow.

Look forward to the pictures, cheers

 

[hawkeyefxr]

Without some pics I don't quite understand your present method, particularly the restriction of vertical cut movement. However, that aside, I would think you have trouble in getting a clean cut as for half of the revolution of the blank you will be cutting 'uphill' against the grain thus risking tearout. The way round this is to turn the blank over every 90 degrees of its rotation so the cutter is always cutting 'downhill'.
I have been doing something similar to this in recent times in producing gear blanks for my clock making activities. For this I've used my disc sander. As with your system, I clamp a sheet of ply to the sander table. I have a vertical brass rod mounted in the ply to take the roughly cut gear blank. I then adjust the position of the ply sheet such that the sanding disc is just biting into the blank. Rotating the blank produces a nice clean disc.
Brian

I know my description is hard to visualise. The vertical cut movement is the plunge cut, I use the fine adjuster on my Elu MOF96 and i run out of movement and have to reset with a shorter bit of studding in the depth stop (even that sound hard to understand).
Your last paragraph sounds like what i am doing where the pivot point is mounted to the ply. Your also right in that as i rotate my disc the cutter travels through end grain then with the grain. I screw a piece of 1*1 to the back of my 12in disc so my fingers are a long way from the cutter as it emerges through the disc.
My discs thickness can be up to 1in thick as well, i do stop about every three rotations and clear the dust away.
I would like to see you setup if possible.

My router insert is quite old so it's bigger than todays Ali ones, i bought it about 23 years ago lol. I can't do much with the router table as it's designed to fit under the workbench in my 12ft*8ft shed. Its quite full in there, A lathe, bandsaw, 12in sander, sliding mitre saw, small planer thicknesser, compressor, mortiser not to mention various boxes for other things, 3 routers, biscuit cutter, drill. i can take three steps in one direction lol.

 

[Yojevol]

I would like to see you setup if possible.

The far end (out of shot) of the jig is pivoted with a screw into the base so that the position of the brass shaft can be adjusted with the clamp on the right. Not very sophisticated but it does the job
Brian

 

[transatlantic]

This may be of interest

https://www.youtube.com/watch?v=_HMneS7nrsE

 

[Trainee neophyte]

You have a bandsaw - would that not do the job? Depth of cut problem resolved, but may not be as clean as the router? [youtube]N6_2h-vo0jA[/youtube]

 

[Steve Maskery]

This is mine.

It consists of a baseboard made in two layers to produce a dovetail slot in it, in which runs a matching piece of wood with a row of holes in it (4mm at 25mm centres, if you are interested)

There is fine adjustment for radii in between pin holes....

...and underneath

That chunk of steel was a weight from a set of vertical blinds. The nuts are nylox, so they an be adjusted to turn snugly without play.

The position of the jig is limited by a stop over the RH side of the RT

So I start with workpiece on the appropriate pin hole, pulled well back from the cutter, advance in until the stop engages, then rotate the workpiece and pull back. Adjust the Bristol Lever and repeat until I have the diameter I want.

 

[hawkeyefxr]

This may be of interest

https://www.youtube.com/watch?v=_HMneS7nrsE

It's a good idea but a bit light for me, and it made my fingers curl lol, cheers

 

[hawkeyefxr]

This is mine.


It consists of a baseboard made in two layers to produce a dovetail slot in it, in which runs a matching piece of wood with a row of holes in it (4mm at 25mm centres, if you are interested)



There is fine adjustment for radii in between pin holes....



...and underneath



That chunk of steel was a weight from a set of vertical blinds. The nuts are nylox, so they an be adjusted to turn snugly without play.

The position of the jig is limited by a stop over the RH side of the RT



So I start with workpiece on the appropriate pin hole, pulled well back from the cutter, advance in until the stop engages, then rotate the workpiece and pull back. Adjust the Bristol Lever and repeat until I have the diameter I want.

That is some router table and i'm envious lol. I am thinking of 'making' a new RT top with two slots, one will have an adjustable pivot to suit my needs, i will take a picture of my setup tomorrow to give you a laugh.

 

[Steve Maskery]

That is some router table .

It's Norm Abrams' DeLuxe New Yankee Workshop design, with an improved fence by, er, me.

 

[hawkeyefxr]

This is my router table, old i know but has served me well, where the studding is shown i will be putting an aluminium channel into the top, each end will have a small metal block drilled to take the studding and held in place each side the locking half nuts.
In the centre will be a threaded block, a bit like a saddle on a lathe, when the studding is turned it will move side to side so giving me any radius i will need.

Not sure if the picture is attached as i can't see it.

 

[hawkeyefxr]

That is some router table .

It's Norm Abrams' DeLuxe New Yankee Workshop design, with an improved fence by, er, me.

He was a "required watching" in the mid 90's for me. He made things look so simple!! I got his plans for making a Cherry wood bed, and still have it to this day, it will out see me. Made it around 2000.

 

[worn thumbs]

Router tables give me the heeby jeebies.Never used one and don't want to,yet I'm quite happy to use an overhead router or even a spindle (for some jobs).I think disc jigs work well with a disc sander as illustrated above in Yojevol's post.Even then there is a sensible limit to the minimum size to be machined on them.I used to work with a 24" Zimmermann that had a factory supplied disc attachment very similar in concept to the jig Steve shows on his router table.It worked very well and by using the lock nut on the adjuster a whole batch of discs could be produced with excellent consistency.I expect because Steve rushed into his workshop to get some useful pictures to illustrate his post he didn't adjust the fence to close the gap around the cutter.Anybody thinking of making such an attachment might need to be reminded that it is a good idea to keep as much of the cutter shrouded as you can and to sneak up on the final size of the disc you are making.

 

[Steve Maskery]

That is a good point WT. I was just photographing the jig, not actually using it.