Everything You Ever Wanted To Know About Spindles from Progressive Hardware

What models should the locksmith stock? A numbering system and the experts at Progressive can help you identify and purchase the right spindle for the job. And two Progressive spindle kits will cover a majority of mortise locks.


The other means of building up the center diameter of a spindle is with “Removable Centers.” This is an easy way to cover several options with one spindle. Use the spindle with two centers, use it with one center or use it with no centers. This type of center is not as substantial as a press on center but in a pinch it will work fine. However, be aware that its life cycle will be shorter.

We have talked a lot about swivel spindles. There is one common problem that pops up because it’s often forgotten. In order for the interior and exterior knobs to work independently, the swivel spindles halves must be able to swivel. To do this, before installing into the lock, lightly screw both halves together and then back off one turn. This is very important.

Photos 20-22 show a spindle being inserted into a mortise lock. Be sure that the center of the swivel spindle is in the center of the lock. Photo 23 shows a typical pair of lock hubs that has been removed from a lock to illustrate the spindle in its correct position HOW LONG A SPINDLE?? The spindle needs to pass through the door thickness, through the thickness of whatever trim is in place and still have enough left over to attach a knob or lever. The easiest answer is to put back the same length you took out. If you don’t have the previous spindle, then you need to calculate a size. Try to measure the overall thickness of the door and trim together at the point the spindle passes through the lock.

Add to this size a sufficient length for spindle to attach your knob or lever. In photo 24, the door is 1-3/4” plus about ¾” of trim. The overall dimension is 2-1/2”. I want the spindle to thread at least 1” into each knob; therefore I want a spindle at least 4-1/2” long. Since my knobs on this lock are hollow, I don’t need to worry about the spindle being too long. Some knobs have a blind hole and levers in particular have this issue. In these cases it may be necessary to be more precise in the length of the spindle or you may have to cut a portion off.

I’ve often been asked what a locksmith should stock. First, know your customer base. Each town or city seems to develop around one or two major manufacturers over its life. But be careful, if a customer calls and tells you he or she has a Sargent mortise lock on their door. Don’t assume the spindle is threaded 3/8-16. It could have been previously replaced and it could be 3/8-20 threads per inch. As long as the knob and spindle are threaded the same, the lock really doesn’t care. Remember, it’s still only a square rod turning a square hub.

To help simplify matters, Progressive Hardware sells two spindle kits that will probably cover a majority of the mortise locks you will service. One kit is for 3/8-20 thread knobs. This is the majority of the country and covers Arrow, Corbin, Marks, National, Norwalk, Russwin and Yale. This is our Number 20. The other kit is for 3/8-16 and 3/8-18 thread knobs. This is aimed at Lockwood and Sargent knobs plus a few other companies. This is our kit Number 1618.

The #45-20-RTP Universal Spindle is always a good bet to keep around plus a pair of 20 thread knobs to go with it. Don’t get hung up on the idea that you have to put 3/8-18 thread knobs on a Lockwood mortise lock. The lock doesn’t care you only need something to turn the square hub. If the knobs fit the trim and the spindle works the lock, you’re done!

We have also developed a numbering system that should help you identify and purchase our spindles. In general:

The first 2 digits indicate if the spindle is Straight (44), swivel (45) or sectional (46).

The next 2 digits indicate the number of threads per inch, 16, 18 or 20.

The last digits indicate some sort of special characteristic.

Therefore a #45-20-P, is a swivel spindle (45), threaded 20 threads per inch (20), with a pin stop (P). A #44-18-5 is a straight spindle (44), 18 threads per inch (18), 5” long (5).

As a reference, Progressive Hardware has an available Spindle Chart that shows pictures of the majority of the spindles that we make.

For more information, contact Progressive Hardware at Telephone 631-757-8866, Fax 631-757-8870, e-mail bill@progressive-hardware.com and online at www.progressive-hardware.com.

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