recess plugs

[Gregg Feldstone]

SImple beginer question? When making a plug for a bowl bottom recess, does one simply keep the sides of the plug verticle (90deg.) or is there a way to match the doevail angle and still get the plug in?

[Dennis Peacock]

Gregg,

If you are talking about a "friction fit" or a "jam chuck", then you'll need to leave off the dovetail and go for straight sides and a nice "press fit" for the bowl. Once you ever try a scroll chuck for turning? You'll wonder how you ever got along without one. :D

[Gregg Feldstone]

I am talking about pluging the recess I have made for my scroll chuck. The recess is dovetailed and I don't want to bother using cole jaws to reverse mount the bowl and straighten the doevetail...just want to reinforce the bottom of the bowl (which I turned too thin) with a plug. Do most turners just try for a good enough fit with precise measurments?

[Scott Hubl]

Gregg,
I don't think most Turners these days use "plugs".

It's a sure sign of going through the bottom or going to thin.

I'm sure if you take calipers and measure the recess diameter at the outmost bottom edge and cut a "plug" to fit it as tight as you can will do the job use some titebond or CA glue and tap it in place.

You may still need to reverse chuck it to finish it off flush and do some kind of detail work to successfully incorporate a plug into the piece without it screaming out "Ive been plugged!"

Maybe insert the "plug" then reverse chuck , dress it up some then add a coin or somthing interesting so it looks to be an inlay ring around it?

Good luck and let us know how it turns out.

[Brian Poor]

I 2nd Scott's observation.

The usual style of any bowl's foot is to remain in some form of recessed state.
Look at a wide range of bowls in different mediums; porcelain, stoneware, glass, wood - they will almost always have 'feet'.

But yes, you can add a plug and salvage the piece you have, definitely.

My own technique for plugs or inlays, is to use a shallow locking taper, instead of straight sides. Similar to a Morse taper.

[Gregg Feldstone]

Brian, how do you get the morse taper into the recess if the widest part is the top of the foot?

[Brian Poor]

You may want to do this on a practice piece first, to try to get the hang of it before plunging into your good piece.

First, cut a plug that has a slight taper to it's side, slightly wider at what will be the outside of the inlay.
With the bowl reverse mounted on the lathe, take a plunge cut that wipes out your dovetail.
This should be approximately what was cut for a taper on the inlay.

The end of the cut that is against the bottom of the bowl will now be the narrow end of the taper.

With practice, this process allows you to readily fit inlays.
The concept behind using a taper is that it is easier to find where the 'fit' is.
After you have done it a number of times, your eye can gauge what you need for a mating taper easily and you can get a press fit that glue will only enhance.

[Don Eddard]

Brian, how do you get the morse taper into the recess if the widest part is the top of the foot?
I believe he's suggesting having the widest part at the bottom of the foot instead. Instead of making 90 degree sides on the plug, taper them a bit so it's bigger on the bottom than the top. Sort of like an upside down rubber stopper. That makes sure you get good contact with the edge of the recess all the way around the plug. It also helps if the recess has a matching angle, though.

There is no way I know of to install a dovetail plug with a bigger diameter at the top unless you're doing it from the inside of the bowl through a hole. ;)

[Bernie Weishapl]

Gregg I had the same thing happen on a bowl one time. I got it to thin in the middle on the bottom. You cannot get a good fit with the plug if your recess is dovetailed. What I did was use my colejaws to reverse the bowl and made the side of the recess straight with a parting tool being careful not to go to deep as to go thru the thin bottom. I then made a plug and just kept taking it taking it down till I had a tight fit. Take light cuts and keep trying the fit. Glued it with Titebond III. When it had dried for 24 hrs. I went and finished the bottom. I used a skew to make a scored line over the glue joint and you couldn't even see it.