Lapping out Hand Wheels


Often, the new reproduction hand wheels that are coming out of China arrive apparently machined to some metric inside diameter that is very, very close to the old American Singer size… but not quite close enough. They either won't go on the shaft, or are so tight that there is no possibility of free-wheeling for bobbin winding. Also, sometimes folks get a machine out of Europe that has a slightly "off" measurement in relation to the size wheel we are attempting to fit.

If you have the right tools, and are comfortable using them, lapping out the inside of the hand wheel is not difficult and really doesn't take much time. There are two easy techniques, both of which are presented here…

Lapping on a lathe…

 

 

This is the technique I use for this job, since I happen to have a wood lathe. Above, Picture 1, you see the hand wheel chucked up in the lathe, which is set to it's slowest speed. In Picture 2 you see me holding a 3/4" wooden dowel with some 600 wet and dry paper wrapped around it. This will slowly be inserted into the shaft hole of the wheel while the lathe turns. Once inside, it is 'worked' back and forth. Be sure the direction in which the lathe is turning matches the direction you have wound the paper. Replace the paper a couple of times. Take the wheel off and check fit. It should spin freely on the machine shaft when oiled. If it doesn't, do more lapping. If necessary, wrap the paper a bit thicker.

Study the brake lapping tool shown below. It would be no big deal to saw a slot in the end of the wooden dowel above and insert the paper in a similar manner.

Note: If the lathe is run at slow speed and you are careful, this is not a dangerous procedure, though you are holding the dowel while the machine is running. A person used to lathe work will not be bothered by this, but if you are not, it is not for rank beginners…

 

And, the brake lap tool technique…

This was sent in by Pat in Michigan City, and I am including her explanation…

 

 

 

Above are three views of the brake cylinder hone discussed below…

 

Hi Captain and All!

While DH agrees that this method works and works well, Captain, there is another method which Chuck has used for years for many different projects. He wanted to offer his methodology:

Go to your local auto parts store and buy a cheap (there are expensive models) brake cylinder hone, using the abrasive that comes with it as a pattern, cut some #400 wet or dry or crocus cloth to fit; chuck it in a hand drill (or drill press which T'Annie probably doesn't have) and run it back and forth through the hole in the hand wheel (check often so you don't get the hole too loose).

This device is good to remove surface rust in the wheel also. Note: the #400 wet or dry paper and crocus cloth are available at the auto parts store also. Also, the #400 cuts faster while the crocus cloth polishes better. I am sending the Captain pictures in a separate post.

Just thought there might be some who would like to try Chuck's method; hope this helps!

Pat in Michigan City, IN

I hope these pictures/discussions are helpful to you.

 Dick Wightman