Don't Laugh! It works

[sawdust maker]

a week or so ago I posted a thread of my attempts to make a jig using a router on my lathe to make some long 4" dia. collums. I failed . Have a look at my previous posting "Some You Win Some You Loose".

But once dropped the idea of using a router, things got better :lol: .
Have a look.

The finish is not bad. My test wood is fast grown softwood, so I am expecting a better finish on the hard wood. The accuracy is very good, less than 0.3mm.

The jig uses the base of the original jig with the addition of spring loaded guards to clear shavings from the lathe bed.

I know it looks a bit Heath Robinson, but it works :lol:
Paul

 

[dicke]

Paul
I always like to see other people inventions, and I am trying to think of one myself ---- A simple set up to turn "off center spindles", Say for instance hammer or chisel handles. Both head stock and tail stock will have to turn in sync. Any bright ideas out there. No No No spokeshave
****

 

[PowerTool]

Nice idea,Paul - same principle as a metalworking lathe,so no reason it shouldn't work well.

Andrew

 

[Anonymous]

Interesting project Paul ....now, if you could rig a jig with a skew to do a planing cut.........

Thanks for the inspiration.... with some adaption of your design I can 'see' a potential copy jig ... but it would take all the fun of 'freehand' away...

but as an old colleague used to say: needs must when the devil drives :wink: (particularly when there's money in it :lol:

Dicke

Both head stock and tail stock will have to turn in sync. Any bright ideas out there.

One possibilty...
at its simplest: a plain disc of say, plywood, with two screws (as centres but at the desired off centre!) held in the headstock and a corresponding disc fitted into a revolving centre (the ones that have interchangeable bits)

Let me know if you can see any flaws in the idea (it's a 'first thought' rather than a considered solution :wink: )

 

[Anonymous]

I like that SP - something I could do with myself as I hate trying to get spindles straight

 

[sawdust maker]

Yes Dicki, setting it up to use a skew rather than a scraper would give a better finish quicker. Two problems, the easy one, getting the angle of cut right. The second more difficult is making a jig simple enough that it keeps it's rigidity but alows fine accurate adjustment.

Your idea for a copier has been done. B&Q were selling a cheep copier lathe. Don't think it worked that well though, they have stopped selling them now. A scraper tool was held in a clamp. The clamp was connected to a "V" shaped former that pivoted at the bottom of the vee. The other arm of the vee ran a long the spindle, that is clamped at the back of the lathe. The vee shaped formed could be wound along the length of the lathe. But if you come up with a better idea using my idea. I claim cope right and want a cut :twisted:

 

[Anonymous]

Dicki? e by gum :shock:

copy... I was thinking more of a plywood former which a 'needle' could follow... for me it'll go on the tuit pile

Skew... daft idea that might work... hinged wedge adjustable with threaded rod with the skew riding in a suitably angled rebate....

Back to the red wine for more inspiration (nowt to do with the name oldsoke :lol: )

 

[sawdust maker]

Now I'm disappointed :shock: I thought you were going turn my idea into something that would to make millions and toss me a few £100,000.
Now I'm heading for the whisky.

 

[Bob Chapman]

Hi Paul,

Your setup looks fine. I think you will improve the finish if you sharpen the scraper at an angle of about 45 degrees and then use a fine stone to remove the burr on the upper surface. If you can arrange the scraper so that the bevel is rubbing (angled upwards) and the cutting edge is about centre height, so much the better. You might be able to get the bevel rubbing by adjusting the grind angle of the scraper and leaving it above centre as you have it now.

Used in this way the scraper ceases scraping and becomes a cutting tool capable of giving a fine surface finish. I call them 'flat gouges'.

Bob

 

[sawdust maker]

Thanks Bob

I will try your suggestions. I have made a change to the jig, in that the tool rest can now be raised above the centre line. Did this in the hope of using a skew chisel to make a smoother cut. Couldn't get the angle right. Your idea sounds much better.

 

[sawdust maker]

After following the advice of Bob I have made a mk3 jig that now works much better. I have completed a test run on making a 3.5" fluted collum which has been split to form four quadrant moldings.

Bob's advice was to shapen the rounder scraper mor like a gouge and present to the wood at an angle. To do this I made an adjustable rest

The rest is spring loaded and the tool cutting edge is lowered by turning the black knob on the top.

I started with four pices of 2"X2" glued together with paper joints.

I was not sure which way to place the wood, cutting with the rings or across them. So I glued the woo up as shown to see which gave the best finish.

Once glued up I rough turned the wood in the normal way.

I then followed with my jig. I started using the chisel as a scraper, with the rest in a horizontal position. Once I was near the finished size I lowered the angle of the rest and used the same chisel as a gouge, attacking the wood in an up ward angle. This produced a much finer finish than before

Once the collum was finished I routed the flutes with a jig described in the Fine Woodworking, Basic turning supplement.

third resulted in loverly even flutes.

Next I split the collum, much easier than I had imagined. To produce these.

All I have to say is thanks for the very useful advice I have got from you all
Thank
Paul

 

[NeilO]

very inventive SM, you just gotta love jigs
mind if i copy your idea???

did you find any difference in the finish, following the grain (growth rings)
(2 on the right of piccy ) or fighting the grain ( 2 on the left ) ??

 

[sawdust maker]

Thanks Neil, be my guest. The only tweak I will be making is the flatten the end of the cutting tool. The one I am using is a half round scraper sharpened to 40 degrees. I think an even better finish will be obtained if the end is flattened so about 1/4" is in contact with the wood. As far as the finish is concerned the grain direction made no difference.

Paul