Adjusting a Misaligned Tenon


On the old Churchill’s bent pot I picked up on Ebay and wrote about in a previous article I spoke of adjusting a misaligned tenon to tighten up the gap between the shank and the stem. Al Jones commented in his reply to that blog post that he would like to hear more about the procedure I used to achieve the correction. I have written this article in response to Al’s question.

The Churchill’s pipe had a slight cant to the tenon. It did not allow the stem to line up correctly. It had a gap at either the top of the bottom of the shank and no matter how it was inserted you could see light in the gap. I have seen the mishaps, and experienced some firsthand, when the tenon is pressed after heating to try to expand it. The misalignment is often dramatic and hard to repair. In the past I have had to just start over with a different stem. I decided to experiment with a different fix on this old Churchill’s.

Churchill 2

Churchill 3

My first attempt at heating the tenon involved the boiling water method that is used to bend stems. I set a bowl of water in the microwave and heated it for two minutes and then dipped the pipe stem, tenon first, into the water to heat it. I repeated that several times until the tenon was pliable and then dried it and inserted into the mortise. I pressed it into place carefully and held it while I cooled it. The results of the first attempt are below – still a gap and the addition of an oxidized stem to remedy. As I thought about the process and the desired end I concluded that a possible issue was that I had not heated the tenon enough to truly get a flexible bend to it. The caution is to proceed very slowly in the process so that you do not snap the tenon and necessitate a different fix.

IMG_1740

IMG_1741

I put the tenon in the shank and left a gap of approximately a ¼ to a ½ inch. I then used heat gun with a tip that reduced the area of the heat to about an inch diameter circle. I held the pipe above the heat and rotated it quickly to evenly heat the gap, and thus heat the tenon. I apologize for the blurriness of the photos but the general set up is clear. Hold the pipe above the heat about three or four inches, rotate it quickly as you do not want to burn the vulcanite.

IMG_1776

IMG_1777

IMG_1778

Once the stem was warm I carefully pushed it into the shank. You want the stem warm enough that the tenon is flexible and not stiff or it will break off as you work it. The tricky part is to slowly and evenly push the stem into place. A variation in the push to either side will only make the problem worse. Once it is tightly against the shank I gently moved it until the fit was tight between the shank and stem. I held it tightly in place with my thumb and fingers as I cooled the stem and shank under cold water to set the new adjustment. It took several attempts to get it to sit properly.

IMG_1780

IMG_1781

Once the cooling was done I held the stem in place for a few minutes as I walked back to my work table. The finished fit was snug and no light shone through the stem shank union as it had previously. I have included the last three pictures below to show the finished fit of the stem to the shank. You can read about the restoration of the pipe in another blog post on the Churchill Bent Pot. https://rebornpipes.wordpress.com/2013/09/08/churchills-bent-pot/

IMG_1772

IMG_1771

IMG_1770

Advertisements

2 thoughts on “Adjusting a Misaligned Tenon

  1. upshallfan

    Thats pretty nifty! I’ll have to give it a try. I don’t have a heat gun, so I’ll have to work with near boiling water. Thanks for the fast response to my request.

    Reply

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.