carriage lock - mark vii

robertk · Post by **robertk** » Thu Jul 02, 2009 1:28 pm

my carriage lock has stopped locking....does anyone know how to adjust it? I wonder if there is any advice before I take it apart?

mbcabinetmaker · Post by **mbcabinetmaker** » Thu Jul 02, 2009 2:19 pm

robertk

Welcome to the forum. I do not have a Mark V11 but it should work the same way as a Mark V. Have you determined if anything is stripped. Unless something is broken or threads are stripped there isn't much to go wrong on the carriage lock. The first thing that I would do is to dissemble the lock and inspect for damage. It could also be foreign materials impacted in there interfering with the ability to lock down. Check these things and get back to us. I am sure we can figure it out.

Glad you joined
Mark

robertk · Post by **robertk** » Thu Jul 02, 2009 5:03 pm

When I turn the carriage lever, it has a slight resistance about every quarter turn. When I watch the mechanism work, I can see that it tries to exert pressure on the carriage rails, but this pressure is not enough to stop the carriage from moving.

I have inspected the lock and its mechanism. It appears that on one end there is the lock lever. On the other end, there is a nut attached to the end of a threaded rod. This threaded rod has a spring and cylinder which tighten and turn against each of the carriage rails.

I have taken the nut off, and have removed one of the cylinders and its spring. Clean as a whistle. I have then reassembled the unit and have tried tightening the nut to put more pressure on the springs - no measurable result.

How can I remove the carriage lock handle and inspect the mechanism that appears to be inside the handle - the handle seems to turn with very little resistance. Is there a mechanism in the lever handle that could have worn out? I have been very gentle with these items so I do not think they are stripped.

mbcabinetmaker · Post by **mbcabinetmaker** » Thu Jul 02, 2009 6:53 pm

Ok we need help from Farmer and Bill Mayo here. Help Help Help.

Don't worry we will figure it out.

Mark

billmayo · Post by **billmayo** » Fri Jul 03, 2009 10:19 am

Farmer has some Mark VIIs and more knowledge about them than me. I have only disassemblied one Mark VII. The carriage lock handle both moves the headstock when turned and locks the headstock when the handle is pivoted.

If I remember correctly, When the handle is pivoted, it pulls the shaft and end wedge lock toward the center of the headstock. It's action appears similar to the 510/520 carriage lock handle action. Therefore I would believe that tighten the end nut should bring the wedges closer together thus locking the headstock when the handle is pivoted. The wedges have a smooth ID and slide on the shaft. I remember having quite a problem disassembling/removing this shaft assembly with the headstock moving gear keyed on the shaft.

I would attempt to tighten the shaft nut until the lock handle is hard to pivot to see if it helps. Hopefully Farmer will jump in here now.

robertk · Post by **robertk** » Fri Jul 03, 2009 1:57 pm

thanks for the advice guys....tightening the screw does not help. From my parts list, there is a piece called a "spacer-cam lock" which is on the handle end of the shaft. Because I get no 'purchase" from the lock when I try to lock the carriage - but I do get a bit of turning action - I am concluding that it is this cam lock which has expired. I'll have to see if I can locate one. For now I am using wood blocks and clamps to hold the carriage.

BUT.....

You guys seem to be the gurus - so I have another question.

Sheave noise, bearing noise...??

My Mark VII was purchased in 1964 (I have the original paperwork). When I bought my house in 1992, the original owner gave me the SS Mark VII. The original owner used it extensively and I have only used it for sanding and drilling occasionally. I have kept it clean and oiled. By coincidence with my carriage lock, I am now getting a sound which to me sounds like a bearing noise.

With the Mark VII in the horizontal position, the sound comes from the belly ....sounding almost like it was from the impeller. I have taken the head cover off and run the machine and all looks well - but the sound definitely comes from near the motor.

With the motor running, there will be no sound for a while, and then there is a sound like a "clutch" or a "speed reducer" kicks in. The sound will go on for a while - 10 seconds or so - and then it sounds like a clutch disengages and the motor runs quietly.

Have you heard of such things before?

JPG · Post by **JPG** » Fri Jul 03, 2009 2:22 pm

robertk wrote:thanks for the advice guys....tightening the screw does not help. From my parts list, there is a piece called a "spacer-cam lock" which is on the handle end of the shaft. Because I get no 'purchase" from the lock when I try to lock the carriage - but I do get a bit of turning action - I am concluding that it is this cam lock which has expired. I'll have to see if I can locate one. For now I am using wood blocks and clamps to hold the carriage.

BUT.....

You guys seem to be the gurus - so I have another question.

Sheave noise, bearing noise...??

My Mark VII was purchased in 1964 (I have the original paperwork). When I bought my house in 1992, the original owner gave me the SS Mark VII. The original owner used it extensively and I have only used it for sanding and drilling occasionally. I have kept it clean and oiled. By coincidence with my carriage lock, I am now getting a sound which to me sounds like a bearing noise.

With the Mark VII in the horizontal position, the sound comes from the belly ....sounding almost like it was from the impeller. I have taken the head cover off and run the machine and all looks well - but the sound definitely comes from near the motor.

With the motor running, there will be no sound for a while, and then there is a sound like a "clutch" or a "speed reducer" kicks in. The sound will go on for a while - 10 seconds or so - and then it sounds like a clutch disengages and the motor runs quietly.

Have you heard of such things before?

My GUESS would be 1)Motor bearing 2)loose impeller 3)loose pulley/sheave

Have YOU been lubricating the sheaves? With the plastic cam, you do NOT want anything to get HOT!:eek:

robinson46176 · Post by **robinson46176** » Fri Jul 03, 2009 4:05 pm

I'm afraid I'm not much help here.

My #1 Mark VII was in good running condition other than the rack gear and everything else worked good. Since I am of the "If it ain't fixed, don't broke it" school, I have not taken the carriage lock apart yet.
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My #2 Mark VII is my "Frankensmith" and I have a Mark V carriage on it.
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My #3 Mark VII is in a storage building and I have barely looked at it. I need to look it over soon and see what it needs to get it going and if I want to get it going. I may still have the original Mark VII carriage from the Frankensmith sitting in the old shop. I'll try to remember to look at it.

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