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A Few Strange Hinges

Interim Hinge by McKinney

Interim Hinge

Above is pictured an interim hinge, used when your door and your frame have different sized hinge preps. For example, your frame is prepped for a five-inch by four-and-a-half inch hinge and your door is prepped for a four-and-a-half by four-and-a-half inch hinge. Why would you need such a thing? Inability to read a tape measure, perhaps?

Wide Throw Hinge

Wide Throw Hinge by McKinney

The hinge above is a wide throw hinge, used when you have a thick molding applied to the pull side face of the door frame. My illustration below shows the difference.

Sometimes people order wide throw hinges by accident because they do not know how to properly measure a full mortise hinge. Full mortise hinges are measured height first, then width. Wide throw hinges have a width that is greater than the height whereas standard hinges do not So if, for example, you order a 5 x 4-1/2 inch hinge you are getting a standard hinge and if you order a 4-1/2 x 5 inch hinge you are getting a wide throw hinge.

Half Mortise and Half Surface Hinges

Half Mortise and Half Surface HInges by McKinney

In the picture above, the half mortise hinge is on the left and the half surface hinge is on the right. As you can see by the “application’ drawings below each hinge, the half mortise hinge has the mortise prep on the door, and the half surface has the mortise prep on the frame. You can tell the half mortise at a glance because the surface leaf is narrow, for installation on the surface of the frame.



The Diverse World of Overhead Stops and Holders

Clockwise beginning at top left: surface mounted GJ 70 and 79 series and Rixson 7 series; Rixson 6 series concealed; bottom right, GJ 81 series surface mount; bottom center, ABH 3400 series with side jamb bracket; bottom left, GJ 90 series surface mount; and above that, ABH 1000A series.

For some applications there is no truly adequate substitute for an overhead stop. Yet many times they are omitted from from hardware schedules where they should be used. But unless concealed OH stops are included at the design stage, retrofitting surface stops to a job after the fact can present a significant challenge.

All overhead stops and holders are designed to accomplish basically the same goals, but in differing situations. If it is a stop, its purpose is to stop the door before it hits something, usually a wall. If it is a stop and holder, its purpose is to stop the door and, under the right circumstances, hold the door open. Overhead stops protect the door closer arm, and they can also make it more possible for the door closer to shut the door in high winds when the stop is templated to allow the door to open to 90 degrees or less. Maximum degree of opening with an overhead stop tends to be in 110 degree range.

Installation of surface-mounted models is simple except when a door closer is involved. Then an amount of thinking and/or additional parts may be required. This is one of the main reasons overhead stops are not often used. However, in at least one circumstance there is no comparable substitute; that is, exterior, high-use, out-swinging doors that are frequently exposed to high winds.

Most overhead stops are sized according to door width and type of hinge used, for example, you would use a 792S (size 2) for a butt hung door with an opening width of 23-1/16 inches through 27 inches, and a 793S for a door with butt hinges that is 27-1/16 inches wide through 33 inches wide. This is information found in the installation instructions. There are also adjustable overhead stops available from most manufacturers; one example is the ABH 1000A series.

The sections below discuss a few of overhead stops shown in the illustration at the top of this article.

Glynn Johnson 70 and 79 Series

Glynn Johnson 70 and 79 Series Surface Mount Overhead Stops
The 70 series is heavy duty and the 79 is extra-heavy duty. These are overhead stops for doors that are regularly exposed to high winds and/or abuse.

At left is a drawing of the 79 Series installed. You can see the problem of where to put the door closer.


One solution might be the LCN 1460 with 62A shoe that significantly lowers the door closer on the door as shown below:

LCN 1460 with 62A shoe and 70 series LCN overhead stop

The drawing above comes from a GJ / LCN applications guide I stumbled upon many years ago. If you look at overhead stop installation instructions, you’ll see they don’t mention a door closer. I have searched for other guides that show door closers with overhead stops, but I have found none.

If you have an aluminum-and-glass narrow stile storefront door with a 3-1/2-inch top rail, you can see that dropping the door closer this much might be a problem. At best, there would need to be a drop plate added that would show through the glass. Not pretty. Another common solution with all surface mount overhead stops is to install the stop on the push side of the door and the closer on the pull side – a viable choice on interior doors, but not usually on exterior doors.

Glynn Johnson 90 Series

Glynn Johnson 90 Series Surface Mounted Overhead Stops
This is the most common type of surface mounted overhead stop, and all overhead stop manufacturer’s make something like it.

In the drawing above you can see the space it takes up on the door. Here’s how it translates into an application with a door closer:

GJ 90 Series with LCN 1460 closer mounted top jamb
Side View, GJ 90 with LCN 1460 series

As you can see, this is not too bad as hardware conflicts go. The measurements are tight, but do-able.

Rixson 7 Series

Rixson Series 7 Surface Mount Overhead Stops
Rixson doesn’t talk much about this overhead stop in their catalog. They say it is ‘industrial duty,’ so, I guess, it must be well suited for high use and abuse environments like factories and warehouses. Much like the heavy spring on the GJ 70 series above, the cantilever design works as a shock-absorber. I included it because if its unique design, which is to say it looks kind of cool.

Rixson 7 Series

Rixson 6 Series Concealed Overhead Stops
All overhead stop manufacturers make concealed overhead stops.

Concealed overhead stops have the distinct advantage that they interfere much less with the door closer installation, however they often make a difficult retrofit, especially on wood doors, sometimes requiring that the door be taken down so the mortise for the track can be cut in.

On a fire rated door this would most likely void the rating.

Rixson 6 Series

Like most Rixson overhead stops, the 6 Series is also available as the 6ADJ Series adjustable version.

Shock absorption is achieved by a heavy spring inside the track. The spring engages at the last seven inches of swing, affording a significant layer of protection for the door closer.

From the Rixson 6 Series install instructions.

The picture taken from the Rixson 6 Series installation instructions shows how much real estate is left on the door for a door closer, and illustrates how much better it is to be working with a concealed overhead stop rather than a surface mounted one.



Occupancy Indicators

In 2018 we have seen a sharp increase in choices available for occupancy indicators for mortise locks. Goodness knows the world can always use more occupancy indicators. One might say that us hardware geniuses now have a dizzying array of indicators available to meet your occupancy indication application needs. Following are some examples of the new choices.

The Schlage lock company advanced with new “180 degree visibility” indicator offerings for their L Series mortise locks, including the new N escutcheon with indicator. Four signage options are available, and indicators are available for use on both the insides and outsides of doors. For example, on a classroom intruder application, LOCKED/UNLOCKED indicators can be installed on both sides of the door, or on a nursing mother’s room, a LOCKED/UNLOCKED indicator inside to reassure the mom, and a DO NOT DISTURB or OCCUPIED indicator outside to stop folks from barging in.

“180 degree visibility” is accomplished by additional indicator windows on the edge of the indicator unit that are visible from the side.
There are many models in this offering of indicators: one for each combination of interior or exterior multiplied by four possible signage choices and for use with either cylinder, emergency screwdriver slot or turn piece.

These indicators are usable with many, but not all L Series functions.   Schlage still offers their original model 09-611 indicator that is included with some mortise lock functions.  Consult your Schlage commercial price book or favorite door hardware genius for more information.

Sargent and Corbin have also increased their indicator offerings for their mortise locks, expanding them to more functions with more signage options, and now including escutcheon trims as well. 

One option offered by Assa Abloy and not by Allegion at this time is escutcheons engraved with the word, “LOCK,” and an arrow indicating the direction one needs to turn the key to lock the door.  This option would perhaps be most notably used for classroom intruder functions, wherein the outside trim is locked from inside the classroom with a key during a security emergency.  The inside trim remains unlocked for safe egress. 

Like the new Allegion indicators, the new Assa Abloy indicator offerings work with select functions and have variable part numbers that reflect the different signage, placement and function of the indicator. 

Usually occupancy indicators can be added to existing locks, as long as the indicator is compatible with the function of the lock.  Replacing a plain escutcheon with an indicator escutcheon is a bit pricier and installation is more complex, but it can be done, once again, if the chosen indicator trim is compatible with the existing hardware.

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Exit Device Retrofitting Adventures

Monarch model 18

As door hardware evolves, new products emerge to replace older products. This may happen because of a design improvement, or because a company changes ownership, but in either case it means that there are older products in the field for which there are no exact replacements. Any door hardware product may become obsolete over time. Today we are talking about exit devices.

Falcon Model 25

In the mid-Twentieth Century mass production of doors was standardized so that the mortise pocket within a door that houses the mortise lock would always be the same size. Before this standardization mortise locks were available in a wide variety of sizes, but from this time forward all architectural grade lock fronts would be eight inches tall by one-and-a-quarter inches wide. Of course this affected mortise exit devices. So when I went to replace a Von Duprin 8875 mortise exit device manufactured sometime between 1897 and 1920, I found that the mortise pocket was only about six inches tall and I had a bit of cutting to do to make the new device fit.

Companies pay varying attention to the ‘retrofit-ability’ of their products. Some companies make it easy to replace an old device with a new one, and some do not. As an installer it is easy to find oneself marooned out in the field, having identified an exit device by its appearance for the purpose of providing an estimate to replace it, only to find out during installation that it is the old version, and installing the new version is either going to be a lot of extra work, or extra hardware that was not on the estimate.

For example, in the late 1990’s Von Duprin redesigned their narrow stile 33 and 35 series exit devices. The rails remained the same, but the heads were completely changed. The old version did not accept a rim cylinder tail piece, and the new one does. This means the old outside trim will by no means work with the new device – a potentially expensive problem if not anticipated.

Similarly the Precision 2000 series Apex devices are not backwards compatible with the old 1000 series trims.

Monarch was bought by Ingersoll Rand and rebranded under the Falcon line of products, now part of Allegion. During these transitions the trims changed part numbers two or maybe three times. Check with your favorite hardware genius as to whether the trim you have will work with the device you need.

The lesson here is not to judge by appearances. The new Von Duprin 33 looks a lot like the old one and the Precision 2000 looks just like the 1000 series. To avoid expensive mistakes, pull the device off the door and positively identify it before you write your estimate.

Both Doromatic and Jackson responded to the need to replace crossbar devices with touch bar devices by creating touch bar versions that fit the same footprint as their crossbar predecessors. The Doromatic 1690 and 1790 devices replace the 1990 and 2090, and the Jackson 2085 and 2095 replace the 1085 and 1095 devices with very little trouble. A big bonus is that a in the case of the 2085 Jackson and the 1690 Doromatic concealed vertical rod devices, you can reuse the exiting concealed vertical rods.





Knowing what you have is the key to knowing what you want.

 

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Compatibility Issues

What’s wrong with this picture?

When specifying door hardware I understand that it can be like being an kid in a candy store.  But like that kid, you may not be able to always get everything you want.   Sometimes “this” might not go with “that.” There are some examples that should be obvious, such as fire rated exit devices with cylinder dogging, since fire rated exit devices must positively latch each time they close without exception and any kind of dogging could prevent that.  But other combinations of options are less obviously incompatible.

One elusive combination of exit device options that pops up sometimes is delayed egress with electric latch retraction.  In most electric exit devices this is almost a contradiction in terms because they use the same mechanism for delayed egress as they do for electric latch retraction, except it works the opposite way.  For example, the Von Duprin Chexit uses the same kind of motor that the Von Duprin EL devices use, except that the Chexit motor pushes out on the latch mechanism while the EL motor pulls in.  What would be necessary I guess would be to build a little transmission so one could shift gears from push to pull to switch from delayed egress to electric latch retraction and back again.

But since no one has yet invented this miniature transmission neither the Sargent Electroguard nor the Von Duprin Chexit currently offer both delayed egress and electric latch retraction in the same device.  The only device I have encountered so far that does offer these two options together in the same device is Detex.  There could be others.  Check with individual factories to be sure.

Two options that are offered together in many, but not all exit devices, with varying degrees of availability, are cylinder dogging and electric latch retraction.   For example, Sargent offers cylinder dogging with electric latch retraction, but only when factory installed.   Von Duprin offers “Special Dogging” (SD prefix) with electric latch retraction.  In this case the effect of cylinder dogging is accomplished by a cylinder operated latch holdback feature in the center case of the device.  (Not quite the same as traditional cylinder dogging.)  Precision can offer cylinder dogging and electric latch retraction in the same device without complication because their electric latch retraction and cylinder dogging mechanisms happen in different sections of the rail altogether.  Corbin and Yale offer devices with cylinder dogging and electric latch retraction in the same device.   Yes, the electric latch retraction and cylinder dogging combo is all over the charts when it comes to availability.

 





As in all facets of life, when in doubt, contact your friendly door hardware genius.

 

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Door Hardware Triage

The Medical Metaphor

medicalAs previously published in Doors and Hardware Magazine, Feb. 2016

As in the medical profession, correct diagnosis of door hardware problems is wholly dependent upon the knowledge, skill and powers of observation of the person whose job it is to correct the problem.  “The devil is in the details,” they say, and it is never truer than when said in reference to doors and hardware.

Another old saying, “ignorance is bliss,” can be liberally applied to who those innocent building occupants and visitors who think that the answer to a lock that is not latching is to slam it until it does – or until the hardware falls off, whichever comes first.  Yet by the same token, door hardware technicians who fail to look at door hardware problems holistically are equally blissful.  If you have ever seen the latch hole in an ANSI strike enlarged to include half the head of the bottom mounting screw in order to remedy what is clearly a hinge problem you will understand what I am talking about.

The above occurs because the technician sent to solve the problem is guilty of treating the symptoms while failing to diagnose the disease.  He or she observes that the latch is making contact with the strike too low to drop into the strike hole as it should, but does not question why this is happening.  This example is a simple one, but the principle applies to more complex problems as well.

Method

A great way to make sure you correctly identify a door hardware problem on the first visit is to have a consistent method of examining the total opening.   An example follows:

  1. If possible, speak with the person who has reported the problem, or better yet, meet with them at the opening so that they can show you what the problem is.
  2. As you approach the door, visually check the gap around the edges of the door on the top and both sides.  (The gap should be one-eighth inch.)  If the gap is greater in one place and less in another, the problem may be a bent hinge or misaligned frame.
    Open the door.  How does it feel?  Does the door itself stick?  If it has a latch, is there resistance when you turn the lever to retract it?  Do the hinges groan or squeak?
  3. Inspect the door for dents and abrasions.  For example, scratches at the top of the lock-side edge may indicate bent or loose hinges.   Dents may indicate attempted forced entry:  check for damage to internal lock parts.  A dent in the gap between the door and frame above the top hinge may mean an object was placed there.  The frame may be damaged and/or the top hinge may be bent.
  4. Inspect the hardware for damage, missing parts and/or wear.   If it is a hollow metal frame, are the silencers installed?  If there are no silencers the door will not align properly and the lock will not latch correctly.  Is the door closer leaking?  Does the door closer arm move smoothly?  Are the hinge screws all present and accounted for, and are they tight?  If there is a latch, there probably is a drag mark on the strike.  Does the drag mark reflect correct alignment?

In other words, look at the door, the frame and the hardware thoroughly and completely, and always do it the same way.  That way you won’t fix one problem just to return the following week to fix another problem that you missed.strike

Tools May Be Required

To identify a door hardware problem you may find it helpful to use instruments or tools.   For example, a carpenter’s level can help you determine whether a door or frame is level or plumb quickly and accurately, and a carpenter’s square can show immediately if the frame is true or sprung.   A tape measure may be helpful to check if hardware is correctly located, whether or not the gap between door and frame is consistently one-eighth inch, and if one leg of the door frame seems to be longer than the other.

One problem most swiftly identified using a carpenter’s level is positive pressure.   If you detach the closer arm and tape back the latch on a door that is level, and it swings open seemingly of its own accord, chances are it’s a positive pressure issue.  Positive pressure occurs when the air pressure inside the HVAC ducts is greater than the pressure outside, causing air to be constantly forced out of the structure.  Positive pressure can be powerful enough to prevent a door closer from closing the door, and sometimes the only cure is when the HVAC technician changes the settings on the air circulation system.

The positive pressure issue is one of those door hardware issues that may require someone besides a door hardware technician to fix.

Waiting For The Electrician

Problems with electro-mechanical and electronic locking systems, like positive pressure issues, may require a low voltage or electronics specialist to solve in addition to a door hardware technician.  For liability reasons it is important to use technicians who are appropriately licensed as required in your locality.

Often these problems are due to mechanical as well as – or even instead of – electrical or electronic issues.  Therefore the best situation for electronic or electrical door hardware triage is when the technician called upon to fix a problem is skilled in all three disciplines. Out in the world we are finding locksmiths that have their low voltage electrical technician license and a working knowledge of how to troubleshoot or program an access control system, systems integrators who can disassemble and repair a mortise lock, and even electricians who can adjust a door closer or repair an exit device.

This is a phenomenon driven by a market that desires to have one technician who can do everything, both for convenience and economics.  In any event, a technician equally skilled in these areas solves the problem of cross discipline communication.  If you’ve ever had to explain the difference between fail safe and continuous duty electrified door hardware to someone who just does not get these concepts you will understand what I’m talking about.

For this reason alone it behooves one in the door hardware repair and installation business to learn as much as they can and get all the credentials they need to be able to service all the door hardware out there in today’s electric and electronic world.

Closure

The age of door hardware in which we work today is the age of the renaissance woman or  man, student of many skills.  However, diagnosing the often complex ailments of doors and door hardware takes more than skill and knowledge:  it requires mindfulness, openness, resourcefulness and humility.  It is not only necessary to know what could go wrong (and doubtless will, according to Murphy’s Law); it is necessary to be aware enough to observe all the symptoms, to be open to all possibilities and to be imaginative in creating solutions.  One must also have the humility to realize that it is not possible for anyone to know absolutely everything.  Sometimes the most useful tool at your disposal is your mobile phone.  A call to factory tech support can often save hours of fruitless aggravation.

 





No man is an island – but some men belong on one. 

The Pressure’s On

balloonPositive Pressure Issues

Sometimes doors are required to perform conflicting functions simultaneously.  For example, in order to comply with the American Disabilities Act a particular door may be restricted to a door closer that requires as little as five pounds of opening force.  This same door may be required to lock automatically without fail.

One solution could be to use a non-hydraulic, motorized power operator (automatic door opener) instead of a standard hydraulic closer.  Since many non-hydraulic power operators do not depend on a spring for closing force it is possible for them to have an ADA compliant opening force and also exert a closing adequate to close and latch the door.  Most power operators that fit this description must be installed by AAADM certified installers.

Without the magic fix of the non-hydraulic power operator, all a door technician can do is fine tune the door so that it swings perfectly and is perfectly balanced; fine tune the locks, hinges and door closer to peak performance under the opening force restriction; and pray there isn’t a positive pressure or wind issue.

One caveat:  deprived of electricity, a non-hydraulic power operator will neither open nor close the door.

Positive pressure HVAC operation is a prime example of how the intended function of a door can be impeded or prevented by the normal operation of building infrastructure.   Positive pressure in a building is accomplished by using the HVAC system to add air from outside the building to the air that is already in the building.  As with a balloon, the added air pushes outwards in all directions.  When an exterior door is opened, air flows out through the open portal, acting as an invisible barrier that keeps outside air out.

Unfortunately positive pressure acts like a constant wind pushing on the inside of the exterior doors.   Since almost all exterior doors swing out, the net effect of positive pressure HVAC on exterior doors is that of blowing to doors open and/or preventing them from closing.

The non-hydraulic power operator idea discussed above can usually solve the problem, but I have had some success adjusting door closers to compensate for positive pressure situations.  I have found that a slow swinging speed followed by a fast latching speed will often accomplish the mission.  This solution, however, can create other problems such as creating a wider time window for unauthorized persons to enter while the door is still shutting, for example.

I have found no reliable fix for an opening subjected to positive pressure that must comply with ADA reduced opening force requirements; however, since positive pressure on out-swinging doors inherently reduces opening force, there is some hope.

In the best of all worlds, door hardware technicians and HVAC technicians work together to coordinate positive pressure ventilation needs with security and ADA compliance requirements.

Excerpt from Tom’s article “Butcher, Baker, Door Hardware Technician… ” published in the February 2015 issue of Doors and Hardware Magazine, magazine of the Door Hardware Institute.

The Obsolete Mortise Lock

Nothing lasts forever.  Like manufacturers of other mechanical devices, lock companies periodically update their products to be consistent with current technology.  They do this to make better, safer, more reliable products, and also to remain competitive in the market place.

Sometimes these new, updated products are backwards-compatible with older models of the same brand, sometimes not.   In the case of mortise locks I can say with some confidence, mostly not.   One cannot replace a Schlage K series mortise lock body with an L series and expect the trim to work.  The same is true of the newer Sargent 8200 vs. the older 8100 and the Yale 8800 series vs. the previous 8700 series.  As these older locks age and must be replaced these differences can become a problem, since the existing trims and cylinders on site may not be usable with the new lock bodies.  And there are still plenty of these older lock bodies out there.  Case in point, although the Yale 8700 series was discontinued in 2006, one facility I know is filled to the brim with these mortise locks.

Although I foresaw that they would not be able to use the existing trims with their new locks I failed to anticipate that the existing cylinders would also be incompatible.  But they were and here is why.  On the left the cam that works with the Yale 8700 is in the process of being removed from a Medeco small format interchangeable core (SFIC) housing.  In the first picture below, the correct cam has been installed.

DSCN4430DSCN4432

 

 

 

 

 

In the second picture you can see that the new cam is not only thinner than the old cam, it’s also slightly longer.  There is no way that old cam is going to work.  Luckily, on a Medeco SFIC housing the cams are interchangeable, unlike most others on which the cams are permanently attached.


Please visit my friends’ site:

http://www.americanlocksets.com/mortise-locks-c-38_159.html


Now I’m waiting to hear about the other SFIC housings on the job that have their cams staked on. But one cluster at time, eh?

The Wrap-Around Door Reinforcer

4CW2A wrap-around door reinforcer is a metal sleeve that slides over the door at the lock prep to conceal damage and/or reinforce the door.  They are a quick and handy solution when wood doors are damaged by forced entry and are often installed to strengthen new wooden doors against forced entry attempts.

In my experience a wrap does not really deter forced entry, but it does limit the damage done to the door.   I have found that when wood doors equipped with wrap around door reinforcers are burglarized, often only the wrap and the lock need replacing, not the whole door.   As with all door security hardware, if your lock is installed in a wrap-around door reinforcer and your neighbor’s lock is not, a would-be burglar may choose to break into your neighbor’s place instead of yours; however, this hypothesis is dependent on the highly dubious notion that a burglar is behaving rationally.  If the person were behaving rationally they would not risk their freedom and personal safety breaking into to somebody’s home to steal  their iPad or PC and selling it for chump change to their drug dealer.

Another benefit to using wrap-arounds is that they can act as a drill guide for lock installation.  Be careful, however, not to let the hole saw chew up the wrap.  Also, especially with stainless steel wraps, be sure not to let your drill bind up with the metal at high speed.  Injury would be likely.

Wraps are typically used on wooden doors, and while it is possible to use them on hollow metal doors, they never seem to fit quite right without a fight.  It seems that hollow metal doors measure exactly 1-3/4 inches thick whereas wood doors tend to measure closer to 1-11/16 inches.  Variations in door thickness affect the way a wrap will fit (or not fit) on a door.

A wide variety of wrap-arounds have been created to accommodate various locks and conditions.  Don Jo Manufacturing currently carries the largest assortment, and if a new kind of lock by a major manufacturer emerges, they are pretty quick to design a wrap for it.  To get the right borewrap for your application you need to know:

  • Door thickness
  • Size of the wrap you want
  • Diameter of the lock bore
  • Backset
  • Finish
  • Through-bolt holes (yes or no)

(see illustration)

Standard door thicknesses for wraps are 1-3/8 inches and 1-3/4 inches.  Some models of wraps are available thicker doors.   Wraps come in a variety of heights, but height is usually determined by the kind of lock the wrap is designed for and the backset.  See the illustration for bore, through-bolt hole and backset details.

For other wraps you may need other dimensions.  For example, Don Jo makes a number of wrap-arounds for interconnected locks and these (naturally) have two bores cut in instead of one.   If you need a wrap for a mortise lock you may have to change the trim on the lock to make it work, or you might have to drill lever, cylinder and thumb turn holes into a blank wrap to customize it to the lock you have.  See my warning about hole saws and stainless steel above.  I earned myself sprained fingers that way once.

I used to joke about certain doors that they could use a door sized wrap.  Then some enterprising individual actually brought one by.  The idea didn’t go anywhere, as far as I know, but it was a good concept:  one wrap covered the door completely in sheet metal and another covered the frame.  Still, at that point why would one just buy a hollow metal door and frame?

And that about wraps it up.

Compact Electric Strikes

A common problem with installing electric strikes is cavity depth – that is, how deeply you need to cut into the frame (or wall) so that the electric strike will fit. For most of the twentieth century electric strikes were, and most still are, designed without consideration for this factor. Instead they are designed for burglary resistance and durability.

VD6211

Von Duprin 6211 Electric Strike

Click on  the dimensional diagram of the Von Duprin 6211 electric strike at right.   You can see that its total depth is 1-11/16 inches. All of its internal parts are heavy duty, and it has a heavy cast body and a thick, finished face plate. Most of the parts are individually replaceable. To install the 6211 in a hollow metal door frame, the dust box must be removed and often material inside the door frame – sheet rock, wood, masonry, whatever – must be removed in order to accommodate the strike. If the strike must be installed in a grouted door frame the installer is in for perhaps an hour’s worth of work that may involve a masonry drill, a 2-1/2 lb. sledge hammer, a masonry chisel and safety goggles.

HES 5000 Dimensional DrawingsIn more recent years a new generation of low profile (shallow depth) electric strikes has become available, offering unprecedented ease of installation. The HES 5000 (illustration at left) was one of the first strikes on the scene to offer a depth of only 1-1/16 inches, and advertised that it could be installed without even removing the dust box from the frame. I have found it is usually much easier to knock out the dust box for wiring reasons, but it is true that the unit will fit neatly inside most original equipment dust boxes in hollow metal frames.

More recent offerings in the shallow depth electric strike department include the Trine 3478, the HES 8000 and the Adams Rite 7440, illustrations shown at the end of this article.  All are UL Listed burglary resistant. The HES 8000 offers 1500 lbs. holding force, the 3478 offers 1200 lbs. holding force and the Adams Rite, with its innovative double keeper design, offers 2400 lbs. of holding force.  The Trine 3478 offers an install with a very tiny lip cutout, and the HES 8000 offers the advantage of needing no lip cutout at all. Each of them fit in a strike cavity only 1-1/16 inches deep.

These strikes have revolutionized electric strike installation. Before, a good installer might install six or ten electric strikes in a day. Now a really fast installer might be able to install 20 or more, greatly reducing labor and other costs associated with installation.

What’s the Trade-Off?

None of the internal parts of these strikes are available. When these strikes break, you throw them away and buy new ones. Also they do not last as long. Whereas it is not unusual to see a Von Duprin 6211 or a Folger Adam 712 still in use after 10 or even 20 years, 6 years of service is a long time for a low profile strike. In ten years you might be replacing a spring or solenoid in a Von Duprin, but you might be installing your second or third low profile strike in the same door frame in that same amount of time. This is a small inconvenience.

Upon installing that third strike in the same hole, you probably will not yet have equaled the price of a single Folger Adam 712 or Von Duprin 6211. If price up front is the primary consideration, low profile is definitely the way to go. But if in about 12 years you are installing the fourth replacement strike in the same prep, those expensive, harder-to-install, heavy duty strikes start to look like a much better value.

strikethree

HES model 8000, Trine model 3478 and Adams Rite model 7440

Thank you.


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