Hole End Mainsprings

Measuring the Hole End Mainspring

A Hole end mainspring is use when the mainspring is contained in a brass barrel.Read More »

Hole End Clock Mainspring

What is being measured below is the sizes of the new mainspring to match up to the old one.

The width is measured first and matched up to the width below, then the thickness is measured with a micrometer, then the approximate length.

So, if you match up the width first, you can then see what spring is closest in thickness and length that will be closest to the old one.

The diameter column is what the spring will fit best, in the inside diameter of the brass barrel. WARNING: Wear safety glasses and gloves if working with a hole end mainsprings, they can and will be dangerous. If you choose, we have a mainspring replacement service, all you have to do is send us the entire barrel.

Determining if the movement is worth fixing

When a hole end mainspring breaks in the barrel the impact may have caused damage in the rest of the gear train.Read More »

It is possible that the pivots that go into the outer plates have bent or the arbors bent some, its best check on this before finding a mainspring.

The length, width, and thickness would need to be measured and then you would match it up on the chart below.

Now if the mainspring has any size at all to it, it would require special tools to reinstall the hole end mainspring into the barrel.

These tools are over a hundred dollars, if the mainspring is larger then it would be very hard to put in and dangerous at the same time.

If the movement is 25-30 years old, it has lived its life anyway. A new movement would be less trouble, cheaper than a over haul, and would last another 30 years, and easier than the repair process.

If you would like to explore the new movement option rather than replacing the mainspring, Please provide the movement numbers off of the back plate of the movement itself and email this information to [email protected] There is another option also, just send us the clock mainspring barrel and we will swap it out with the correct new mainspring for a fee.

Hole End Clock Mainspring

Hole End Mainspring replacement service

We can do the task of measuring and installing the mainspring if you choose to send it in. Read More »

If going with the mainspring replacement because the clock is still in good shape or out of production new, then if you choose to send the entire barrel with the mainspring in it, we can swap it out for $30.

We will take out the mainspring and measure the width / thickness and approximate length and then install the correct spring back into the barrel.

If doing this please send to Clockworks PO Box 339 Huntington MA 01050 with your contact information.

It may be best also to send us an email to [email protected] so we can look out for the package.

It will end up being the 30 charge, and then add the price of the mainspring as stated in the below chart, and then shipping back to you.

If you would like to send in your barrel with the broken mainspring, please fill out the form at this link so we know its coming into us.

Removing a barrel and spring

Most often the barrel with the mainspring inside of it can be removed from the clock without disassembly of the clock movements outer plates.Read More »

This can be done with a mainspring let down tool, a device that allows you to hold the tension of the mainspring with your fist rather than your precious and fragile fingers. The idea is to put the mainspring let down tool over the square post that the key is to go onto, and then move the "click" out of the way with a flat screwdriver, and slowly allow the mainspring to unwind in your fist as you control the speed of the unwind easily with your whole fist rather then the fingers with a key.

To try this with a key usually ends up being a painful experience on the fingers. You will see the click that with its tension spring that your supposed to hold back, this click is what holds the mainspring to wind in only one direction.

Of course if the mainspring is broken, there usually is no worry as there is not much tension on the mainspring to begin with, but just to be safe on the movement, its best to be sure is in the totally unwound position.

Clear

HEMSP: $9.89$39.89


Hole End Mainsprings Measurements to item #
WIDTH inch | mm THICKNESS inch | mm LENGTH inch DIAMETER mm Item #
3/32" | 2.3 .007" | 0.18 18" 14 CMH 100
5/32" 4 .008" | 0.2 24" 17 CMH 101
5/32" 4 .011" | 0.28 26 1/2" 22 CMH 103
3/16" 4.8 .009" | 0.23 24" 17 CMH 104
7/32" 5.6 .008" | 0.2 26" 20 CMH 105
7/32" 5.6 .0095" 0.24 24" 18 CMH 106
1/4" 6.4 .011" 0.28 15 3/4" MB CMH 109
1/4" 6.4 .011" 0.28 39" 26 CMH 110
9/32 7 .007" 0.18 44" 19 CMH 111
9/32 7 .010" 0.25 18" MB CMH 112
9/32" 7 .010" 0.25 39 1/2" 25 CMH 113
5/16" 8 .008" 0.2 27" 18 CMH 114
5/16" 8 .010" | 0.25 28" 19 CMH 116
5/16" 8 .010" | 0.25 32" 23 CMH 117
5/16" 8 .010" | 0.25 39 1/2" 25 CMH 118
5/16" 8 .011" | 0.28 45 1/4" 28 CMH 119
5/16" 8 .015" 0.38 40" 34 CMH 120
5/16" 8 .016" 0.41 54" 38 CMH 121
11/32" 8.7 .013" 0.33 66" 38 CMH 122
23/64" 9 .011" 0.28 45 1/4" 28 CMH 124
23/64 9 .0125" 0.32 18 1/2" MB CMH 125
3/8 9.5 .011" 0.28 48" 26 CMH 126
3/8" 9.5 .014" 0.36 48" 32 CMH 127
3/8" 9.5 .017" 0.43 54" 38 CMH 128
25/64" 10 .011" 0.28 45 1/4" 28 CMH 130
25/64" 10 .012" | 0.32 73" 40 CMH 131
7/16" 11 .010" | 0.25 32 1/4" 22 CMH 132
7/12" 11 .011" | 0.28 49" 28 CMH 135
7/16" 11 .0155" | 0.4 55 1/2" 38 CMH 136
15/32" 12 .010" | 0.25 39 1/2" 25 CMH 137
15/32" 12 .012" 0.3 53" 32 CMH 139
15/32" 12 .014" 0.36 72" 41 CMH 140
15/32" 12 .013" 0.33 27" 25 CMH 141
1/2" 12.7 .013" 33 60" 36 CMH 142
1/2 12.7 .015" 0.38 36" 25 CMH 143
1/2 12.7 .016" 0.41 65" 32 CMH 144
1/2" 12.7 .018" 0.46 60" 38 CMH 145
33/64" 13 .010" 0.25 39 1/2" 25 CMH 146
33/64" 13 .010" 0.28 45 1/2" 28 CMH 147
33/64" .012" | 0.3 53" 32 CMH 148
33/64" 13 .014" | 0.36 38" 30H CMH 150
33/64" 13 .022" | 0.55 28" 32H CMH 151
17/32" 13.5 .010" | 0.26 72" 34 CMH 149
35/64" 14 .011" | 0.28 45 1/4" 28 CMH 152
35/64" 14 .011" 0.28 49" 30 CMH 153
35/64" 14 .012" 0.3 61" 35 CMH 155
35/64" 14 .0155" 0.4 37 1/2" 36 CMH 156
9/16" 14.3 .012" 0.3 39" 28 CMH 157
35/64 14 .013" 0.33 27" 25 CMH 158
35/64 14 .014" 0.36 32" 30 CMH 159
9/16" 14.3 .015" 0.38 42" 28 CMH 160
19/32" 15 .011" 0.28 45 1/4" 28 CMH 161
19/32" 15 .011" | 0.28 49" 30 CMH 162
19/32" 15 .012" | 0.3 53" 32 CMH 163
5/8" 16 .010" | 0.25 39 1/2" 25 CMH 164
5/8" 16 .011" | 0.28 45 1/4" 28 CMH 165
5/8" 16 .011" | 0.28 49" 30 CMH 166
5/8" 16 .013" 0.33 78" 34 CMH 167
5/8" 16 .013" 0.33 105" 47 CMH 168
5/8" 16 .014" 0.36 70" 39 CMH 169
5/8" 16 .016" 0.41 59" 35 CMH 170
5/8 16 .0175" 0.45 43 1/2" 37 CMH 171
5/8 16 .018" 0.46 41" 36 CMH 172
5/8" 16 .018" 0.46 72" 40 CMH 173
5/8" 16 .018" 0.46 96" 53 CMH 174
43/64" 17 .010" | 0.25 72" 34 CMH 176
43/64" 17 .010" | 0.25 39 1/2" 25 CMH 177
43/64" 17 .011" | 0.28 45 1/4" 28 CMH 178
43/64" 17 .011" | 0.28 49" 30 CMH 179
43/64" 17 .018" | 0.46 54" 40 CMH 180
11/16" 17.5 .012" 0.3 72" 30 CMH 181
11/16" 17.5 .014" 0.36 54" 34 CMH 182
45/64" 18 .018" | 0.46 44" 38 CMH 183
11/16" 17.5 .018" 0.46 96" 53 CMH 184
45/64" 18 .011" 0.28 45 1/4" 28 CMH 185
45/64 18 .011" 0.28 49" 30 CMH 186
45/64 18 .012" 0.3 53" 32 CMH 187
45/64" 18 .012" 0.3 61" 35 CMH 188
45/64" 18 .016" 0.41 56" 39 CMH 189
45/64" 18 .016" 0.41 61 1/2" 42 CMH 190
45/64" 18 .0175" | 0.44 70" 45 CMH 191
45/64" 18 .019" | 0.48 47" 35 CMH 192
45/64" 18 .021" | 0.53 48" 40 CMH 193
3/4" 19 .009" | 0.23 72" 33 CMH 194
3/4" 19 .010" 0.25 39 1/2" 25 CMH 195
3/4" 19 .011" 0.28 45 1/4" 28 CMH 196
3/4" 19 .011" 0.28 49" 30 CMH 197
3/4" 19 .011" 0.28 50" 30 CMH 198
3/4 19 .012" 0.3 53" 32 CMH 199
3/4 19 .012" 0.3 61" 35 CMH 200
3/4" 19 .012" 0.3 75" 35 CMH 201
3/4" .012" 0.3 90" 35 CMH 202
3/4" 19 .014" | 0.36 90" 35 CMH 204
3/4" 19 .015" | 0.38 72" 36 CMH 205
3/4" 19 .0155" | 0.4 53 1/2" 37 CMH 206
3/4" 19 .016" 0.41 53" 38 CMH 208
3/4" 19 .016" 0.41 56" 39 CMH 209
3/4" 19 .016" 0.41 60" 38 CMH 210
3/4" 19 .017" 0.43 44" 35 CMH 211
3/4 19 .017" 0.43 45" 36 CMH 212
3/4 19 .0175" 0.44 70" 45 CMH 213
3/4" 19 .018" 0.46 96" 53 CMH 214
3/4" 19 .019" 0.48 68 1/2" 45 CMH 215
25/32" 20 .011" | 0.28 49" 30 CMH 217
25/32" 20 .012" | 0.3 53" 32 CMH 218
25/32" 20 .012" | 0.3 61" 35 CMH 219
25/32" 20 .0155" | 0.4 53" 38 CMH 220
25/32" 20 .016" | 0.41 53" 38 CMH 221
25/32" 20 .0175" 0.44 70" 45 CMH 222
25/32" 20 .018" 0.46 76 1/2" 48 CMH 223
53/64" 21 .011" 0.28 45 1/4" 28 CMH 224
53/64" 21 .011" 0.28 49" 30 CMH 225
53/64 21 .012" 0.3 53" 32 CMH 226
53/64 21 .012" 0.3 61" 35 CMH 227
53/64" 21 .0125" 0.32 67" 38 CMH 228
53/64" 21 .015" 0.38 100" 50 CMH 229
7/8" 22.2 .011" 0.28 49" 30 CMH 230
7/8" 22.2 .012" | 0.3 53" 32 CMH 231
7/8" 22.2 .012" | 0.3 61" 35 CMH 232
7/8" 22.2 .0125" | 0.32 67" 38 CMH 233
7/8" 22.2 .013" | 0.33 72" 33 CMH 234
7/8" 22.2 .0155" | 0.4 50" 37 CMH 235
7/8" 22.2 .0175" 0.44 70" 45 CMH 236
7/8" 22.2 .018" 0.46 84" 49 CMH 237
7/8" 22.2 .018" 0.46 96" 53 CMH 228
7/8" 22.2 .0195" 0.5 56" 42 CMH 239
61/64 24 .0175" 0.44 70" 45 CMH 240
61/64 24 .018" 0.46 76 1/2" 48 CMH 241
61/64" 24 .018" 0.46 80 1/2" 50 CMH 242
63/64" 25 .018" 0.46 78 1/2" 49 CMH 243
1" 25.4 .018" 0.46 96" 53 CMH 244