Bolt threads on old safes

[00247]

Seeing that there are knowledgeable forum members and some across the pond, maybe some light can be shed on bolt threads.

I am working on a 1891 Mosler screw door and it has metric threads. Not modern day metric but old world metrics. I first noticed it with the mounting bolts for the time locks. Luckily, even though I was missing both time locks, I did locate 2 Yale Triple L time locks and both had the mounting bolts included.

Next, on the door pivot bolts, the threads were all damaged as Mosler had hidden lock bolts covered with filler. I discovered this while battling the first pivot bolt but despite drilling and using an easyout on the others they were all damaged as the safe had been taken apart at some point earlier in it's life. The machinist said, "What the hell kind of threads are these?" No matter, he can duplicate anything so he made two new lower pivot bolts (easy to make) and weld repaired and match cut the upper bolts. (difficult to make the whole bolt)

Now I need some new bolts that hold the inner screw door threads. Again odd threads. I picked up a metric thread gauge so I know what I am dealing with and although it tells me the thread pitch, I can't seem to match up to thread charts I find on line.

The current bolt has the old British 11G 55 degree Whitworth thread, not unusual in of itself. What's odd is it is on a ~1/2" bolt and according to Whitworth thread charts that thread is used on a ~5/8 bolt. On another Mosler I have there is a 5/8 with 11G Whitworth threads. Back to the machinist.

So what I am guessing... Mosler cut whatever thread they wanted on the bolts they made?

I also noticed that the bolts in the Yale time lock are also different. Anyone familiar with them?

The point is, if your buying an old safe, beware of missing or damaged bolts. It can get time consuming and expensive for replacements.

[Chubby]

I was given a whole load of new countersunk allen bolts that were as hard as a mother in law's heart. When working on old Ratners, milners etc. at first I simply ran the correct size metric tap through and replaced the old ones. (I hate those old screws which always seemed to develop finger slicing edges). Of course this wasn't restoring safes to the original, it was just working on safes as quickly and efficiently as possible.

After a while I realised that a modern bolt is so hard I could, actually, dispense with the tap and just put the metric bolts straight in. They made their own thread.

[Doug MacQueen]

Matt and I are currently working on one of those old Mosler screw doors. I don't have immediate access to the safe but I do have the Yale time lock case mounting screws. A quick check shows them to be a 7/16 x 16 TPI as near as I can tell, which is an uncommon TPI in that size. I am thinking Yale may have supplied mounting screws on request, but more likely the safe maker would supply them. Standardization would not have been a widely accepted practice in the 1890's, so you do see a lot of oddball threads. Doubtful Mosler would spec metric or Whitworth sizes, however some of the machinists working there could be recent immigrants from Europe.

[00247]

Yes, Doug, 7/16 - 16 TPI is what I have. A strange thread indeed. All the bolts on a screw door are not a SAE thread or at least not standard size. There are a number of bolts, including the hidden lock bolts that are very close to 3/8 NC 16 TPI but interference starts after 4-5 revolutions. Even the flat head countersunk machine screws for cover plates are close to SAE but slightly different. The heads are of a different size also.

It is nice to replace plated bolts with stainless that I polish if the originals are beat up but on these two Moslers I have been forced to rework the old ones and send them off for new nickle plating. I was fortunate to find a parts safe that supplied not only a time lock but extra hardware, combination lock, and misc parts.

Another odd bolt is the one in the Mosler lock which I believe is a 5H? The shoulder bolt that the fence rotates on seems to be a 1/4 32 TPI and will thread into a 1/4 32 nut although loosely. A 1/4 32 bolt will not thread into the case as it is to large. I am missing one of these bolts but have located one in Arizona and am working on the purchase. Unfortunately, there are a couple models of this lock and each has a different length bolt.

About this lock, I see it is awfully similar to a Yale lock of the same design. Did Mosler make their own locks or did Yale make some for them?

I'm curious which model screw door you and Matt are working on, have a picture?

[Doug MacQueen]

Here is the model but not the same safe. I am currently looking for a good Yale time lock and a Yale/ Mosler 5H comb lock for this safe. I have yet to find out exactly when or if Mosler was ever making the locks. I do know that Mosler at some point had a lock manufacturing plant in Covington KY, and they were making their own lock models, but these were entirely different from the Yale's.