Questions about assembling lock kits

[rich pierce]

I don’t want to hijack Chris’s topic on building locks so will ask here.

I have assembled some lock kits before thstbhave the tumbler hole drilled and reamed and the holes all spotted.

Let’s say I have a pile of much rougher lock castings without all the hole locations spotted. I do have a spot in the plate for the tumbler hole.

Here are my proposed steps.  Will these work?

1) drill and tap and attach pan and bolster.
2) turn tumbler, drill and tap it for the cock screw, and face it.
3) double check the tumbler location, that cock settles where it should. Drill tumbler hole in lockplate slightly undersized. Ream hole. Question: what kind of reamer and where do I get it?
4) make sear the correct thickness, based on tumbler thickness and drill it for the sear bolt.
5) locate the sear so it engages tumbler properly and pivots without the sear arm falling beneath lockplate. Drill and tap plate for sear.
6) Locate the bridle.  File the legs to give a few thousandths of clearance for tumbler and sear.  First drill for tumbler axle (this worries me most) then install on tumbler. Then locate it so sear bolt hole works, then drill for sear bolt.  Drill for upper bolt last, and tap lockplate. Check all works right.
7) Locate sear spring, drill spring and drill and tap lockplate. Cut the slot for the sear spring tab into lockplate.
Locate the mainspring, undercut the bolster or drill and tap for spring upper arm attachment bolt, file the pivot tab so it’s just a pin, and drill the lockplate for the pivot pin.
9) Fit frizzen and solder to pan and drill and tap lockplate and frizzen pivot for pivot bolt.
10) Locate frizzen spring and drill and tap spring and lockplate.

Polish, harden and temper parts, assemble, tune.

[ddoyle]

Rich,

The below maybe has application to your #6. Worked for me but I am overtly paranoid about cockeyed ness. Helps  lining up the holes in plate and bridle. 

Took  a piece of drill rod and turned it to approximatley what I thought the tumbler bearing surface would turn down to.
I center drilled a short length of this so that it could be used as a drill guide to get the bridle drilled.
The remainder of the drill rod was ground into a d-bit which acts as a reamer to make the tumbler hole in the lockplate.
The bridle was drill after it was installed on the lockplate. (and after the hole in the lock plate is reamed)
 Once all that was done then I turned down the two bearing surfaces of the tumbler to be a tight fit. per Mr Rase's advice I used some valve grinding compound to improve the fit. It happens fast.

The above was used when bushing locks. I thought it was required so that I would not need to move the sear. i.e I really wanted the tumbler to be where it was suppose to be in relation to the sear. Worked a treat.

Reamers can be kind of pricey. As alternative Grinding 3 flats (that come to a point) on a drill rod works remarkabley well as does a D-bit. exc quality Small hand reamers for frizzen screw axle etc can be purchased overseas (everything is overseas for canadians )  for fair money. They come in .1 and .05 mm steps real nice kit. Larger metric size machine reamers seem to be hit and miss lots of garbage. But they all make round holes.

[M. E. Pering]

Rich,

The size of the tumbler hole to drill depends entirely on the size to which you turn the tumbler axle.  For example, if I made a 1/4" axle, I would first center-punch where I wanted the hole, and drill to 1/8".  Then I would follow that drill with a 15/64" drill.  Then I would ream to 1/4".  I would try this procedure first on a piece of scrap to make sure your reamer is cutting precisely.  I have gotten decent reamers here:

http://www.grizzly.com/reamers  OR  https://www.mcmaster.com

I am not affiliated with either company, but have received good service from them in the past.  Mostly imported tools, but I have been satisfied with the quality.  Any good machine tool supply company should be able to set you up with almost any size.

[David R. Pennington]

I made my own reamers. Forge long square taper on piece of steel. File true and square. Harden and temper. Finish with oilstone. Larger ones I make square on opposite end for bit brace. Smaller ones (like for locks) I put handle on to turn by hand. Ream a little at a time from both sides. Like DDoyle said it happens fast.

[FDR]

I have used MSC for years for reamers and drills.

https://www.mscdirect.com/

Fred

[rich pierce]

Good advice fellas.  I will investigate those leads on reamers. Doyle, pardon my ignorance but what is a D-bit?  Round stock filed away to a D shape?  found a good YouTube video on D bits

Does the sequence seem like it’s right on a set of castings where not all the holes are spotted, or where one might have to mix and match and possibly make some parts?

[Bob Roller]

Good advice fellas.  I will investigate those leads on reamers. Doyle, pardon my ignorance but what is a D-bit?  Round stock filed away to a D shape?

Does the sequence seem like it’s right on a set of castings where not all the holes are spotted, or where one might have to mix and match and possibly make some parts?

Any half way decent industrial supply business should have any size reamer
in decimal or metric.Use a threading fluid when reaming so the hole won't
be oversize.
I won't offer any advice on a lock kit because I have never tried to make a
lock with one but will say an 8x32 screw holding the cock is too big and I
I use a 6x40.

Bob Roller

[Long John]

Rich,

On locks that I recently received, assembled by the vendor, (Not Chambers, Grrrrrr) the hole in the bridle was not drilled on-center, creating all sorts of problems.  When I finally received replacement bridles I installed the bridles and then used the tumbler hole as a drill guide of sorts to spot the hole location for the pivot pin of the tumbler.  This assured me that the lock plate and the bridle had concentric holes.  If I am in a situation where I have to build a lock again (likely) I think I will try to attach the bridle BEFORE I ream the hole in the lockplate so I can use that hole as a drill guide.

Best Regards,

JMC
John Cholin

[ddoyle]

Doyle, pardon my ignorance but what is a D-bit?  Round stock filed away to a D shape?

Yes a D-bit is a true round hole forming reamer/drill. To make one you simply grind/file away half the diameter of a piece of drill rod. The size of the drill rod will be the size of your reamer. commercially available but most commonly shop made. The face end of the rod is ground at slight angle. Forms a single point cutting tool. Makes a nice hole. start it in a hole that it will just start in. It wont drill with out a big pilot.

An easier and acceptable reamer can be made by simply grinding a 3 sided point onto the end of a piece of drill rod that is the size of the hole you want.  No good for deep holes cause they will jam but for the depth of a lock plate they work great forming a round straight sided hole to size. You will often find dozens of them amongst old clock maker's tools and in the bottom of old tool boxes. Use to be a thing before we got too smart.

If you were always working with the same size holes and tumbler bearing sizes then I'd say get a store bought US reamer but for hobby lock stuff it is more convinient to adapt the tools to the parts at hand. Easier to ream a smaller hole then to add metal onto a tumbler - Imagine a world where instead of drawers full of half worn, never the right size drill bits you have a couple length of drill rod and a few strategic drills bits. I stopped trying to fight drill indexes, what a relief.

[rich pierce]

Great advice. In talking with a toolmaker about possibly using a tapered teamed to get close then lapping it in, I could hear him squirming and wincing on the other end of the phone. D- bits sound like a good choice. Potentially I could turn the tapered points on some drill rods on a friend’s lathe then prep the D bits when I need them.

[Clint]

Everything on this post sounds good to me. The main difference that I practice is that I assemble the tumbler and the sear onto the bridle before I drill the plate. After you fit the tumbler to the plate, the package of tumbler sear and bridle can be rotated together to get the best hammer down and full cock combination. The bridle pin is drilled first, then the bridle screw is drilled and tapped and last of all the sear screw. Most of my locks are scratch built so there aren't any dimples to follow. I love building locks from casting sets though because I don't have to make all the parts.

[Bob Roller]

Good advice fellas.  I will investigate those leads on reamers. Doyle, pardon my ignorance but what is a D-bit?  Round stock filed away to a D shape?

Does the sequence seem like it’s right on a set of castings where not all the holes are spotted, or where one might have to mix and match and possibly make some parts?

Any half way decent industrial supply business should have any size reamer
in decimal or metric.Use a threading fluid when reaming so the hole won't
be oversize.
I won't offer any advice on a lock kit because I have never tried to make a
lock with one but will say an 8x32 screw holding the cock is too big and I
I use a 6x40.

Bob Roller

After I wrote this, I received,unordered from TOW a fine set of castings for a TVLLE lock.
I MIGHT try to assemble it but I am not sure if I will or not.It was a gift and beyond that
I think he wanted me to critique it and I told him it looked very good to me but on another
line of thought,only time and use plus taking care of anything is the final judge of the real
quality of anything.
Bob Roller