Looking for a Mark VII speed change follower

[zenman]

Looking for the follower which goes around the porkchop for speed control in the original mark vii also looking for the sheave that it is pressed into. I have been replacing the bearings on mine and one of the followers broke while pressing the bearing out, and another of the sheaves split while pressing the follower out. that can be fixed if need be,

anyone still parting a mark vii?

[db5]

Not sure what a speed change follower is. I still have a lot of things left from my Mk VII. You can PM me or post a picture of what you need and I'll see what I have.

[zenman]

Here is what the follower looks like.
the thing on the left center of the picture.
it is the rectangular thing with pins and spins on the center of the sheave.

Sent pm.

[larrycz]

I have the same problem you faced, with my M7 sheave. My cam is usable, although it has some damage. But the sheave it pushes on is in bad shape. It has a hogged-out bronze bushing I think due to lack of lubrication on the drive shaft. The bushing is worn to an oblong hole where it rides on the shaft, and is severely damaged by the cotter key as well. From your post, it seems the follower broke while pressing out the bronze bushing? Does this mean you had previous success in replacing this bushing? I was thinking that maybe I could get a machinist to mill out the bushing and fit another? I did some searching on this forum and I'm picking up hints that maybe others have had success in replacing these bushings? In my case the plastic pork-chop shaped cam and the fork follower that rides on it are more-or-less ok but the control sheave is hosed. SS told me they have no parts and to check the web and this forum. They also said that the M5 speed control can't be retrofitted to the M7.

[billmayo]

I have the same problem you faced, with my M7 sheave. My cam is usable, although it has some damage. But the sheave it pushes on is in bad shape. It has a hogged-out bronze bushing I think due to lack of lubrication on the drive shaft. The bushing is worn to an oblong hole where it rides on the shaft, and is severely damaged by the cotter key as well. From your post, it seems the follower broke while pressing out the bronze bushing? Does this mean you had previous success in replacing this bushing? I was thinking that maybe I could get a machinist to mill out the bushing and fit another? I did some searching on this forum and I'm picking up hints that maybe others have had success in replacing these bushings? In my case the plastic pork-chop shaped cam and the fork follower that rides on it are more-or-less ok but the control sheave is hosed. SS told me they have no parts and to check the web and this forum. They also said that the M5 speed control can't be retrofitted to the M7.

I believe I used the Mark V Control Sheave and Idler Sheave on the Mark VII idler shaft. I machined the Mark V Control Sheave bearing depth another .050" deeper so I could stake the bearing with the Mark VII speed cam follower. I would be happy to try this change if you wished to mail me the Control/Idler sheave and shaft assembly. I have a metal lathe so have been able to even machine collars to go over the Control Sheave end to hold the bearing. I have a hydranic press I used to press together this collar and Control Sheave. Contact me off-line if interested.

[JPG]

I believe I used the Mark V Control Sheave and Idler Sheave on the Mark VII idler shaft. I machined the Mark V Control Sheave bearing depth another .050" deeper so I could stake the bearing with the Mark VII speed cam follower. I would be happy to try this change if you wished to mail me the Control/Idler sheave and shaft assembly. I have a metal lathe so have been able to even machine collars to go over the Control Sheave end to hold the bearing. I have a hydranic press I used to press together this collar and Control Sheave. Contact me off-line if interested.

I think Bill likely shortened the 'snout' as well.

I think Bill has provided a solution to your 'problem'.

I had a M5 control sheave become so badly worn to allow it to 'skip a vane' and become jammed. The key way was also severely worn. Yes too little tlc and lubing over almost a half century.

I would also replace the key as a minimum and both sheaves as I am sure Bill will Recommend.

New bearings at this time would also be in order.

A 'permanent' solution to your plastic cam exists, although it is not inexpensive. If 'he' does not offer you an aluminum cam, I will PM you with his 'nom de forum'.

P.S. Notice I also had a problem with the control sheave 'snout' retaining the bearing. Notice the jb weld in 'our' pix you posted. ;>}

[damagi]

Looking for the follower which goes around the porkchop for speed control in the original mark vii also looking for the sheave that it is pressed into. I have been replacing the bearings on mine and one of the followers broke while pressing the bearing out, and another of the sheaves split while pressing the follower out. that can be fixed if need be,

anyone still parting a mark vii?

I have a bunch of Mark VII parts left over. Contact me via email and we can work something out. If you send me photos of what you need, I can send you photos of what I have.

[zenman]

my follower broke while pressing out the inside diam of the bearing away from the folower axis. we didn't support the follower properly in the arbor press and the follower broke under really low pressure. broke like a piece of cheddar cheese. cast aluminum.

we had two bearings to replace. the first one popped out easily. the second must have had a lip surrounding the bearing center. even after the follower broke we tried to press the bearing out, and it took a lot of pressure.

not sure what to do next time to guarantee the bearing pops out easy like the first. those bearings were really bad.

jpg, good to see that I am not the only one cracking the sheave. my mechanical guy never expected the sheave to crack and broke it about 20 seconds after starting the pressing. another story. we have a smithy lathe so we will turn and press on a collar once the follower is replaced. or do you think jbweld will be good enough to hold the bearing.

[billmayo]

my follower broke while pressing out the inside diam of the bearing away from the folower axis. we didn't support the follower properly in the arbor press and the follower broke under really low pressure. broke like a piece of cheddar cheese. cast aluminum.

we had two bearings to replace. the first one popped out easily. the second must have had a lip surrounding the bearing center. even after the follower broke we tried to press the bearing out, and it took a lot of pressure.

not sure what to do next time to guarantee the bearing pops out easy like the first. those bearings were really bad.

jpg, good to see that I am not the only one cracking the sheave. my mechanical guy never expected the sheave to crack and broke it about 20 seconds after starting the pressing. another story. we have a smithy lathe so we will turn and press on a collar once the follower is replaced. or do you think jbweld will be good enough to hold the bearing.

After cracking a few control sheave columns, I machined some hand tools to help me remove and replace the bearing. It is not as easy as it looks. Any cocking of the bearing being removed or inserted will normally crack the housing. Also just using LocTite or other similar glues without having room to stake the bearing could result in failure in the future when the bearing pulls out of the control sheave column. Normally a lack of lubrication after the repair will cause this problem in a year or two. Shopsmith varied the bearing depth over the years. Therefore, many control sheave bearing depth is not enough to allow room to stake. I have to machine most of my control sheave bearing depths to .0275", .235" for the bearing and .040" for staking.

JB Weld would be a waste of time in this case. JB Weld will not hold up where there are any vibration or any side pressure being applied the the parts being put together. Only go for the machined collar that will be pressed on the control sheave column stem. This takes a really knowledgeable machinest to do this work. Setup takes time to do accurately. I still use LocTite 271 even through I am pressing on the collar and installing the bearing. Be sure to leave enough material on the end of the bearing end of the collar to be able to stake over the bearing at each 90 deg point.

[JPG]

. . .

jpg, good to see that I am not the only one cracking the sheave. my mechanical guy never expected the sheave to crack and broke it about 20 seconds after starting the pressing. another story. we have a smithy lathe so we will turn and press on a collar once the follower is replaced. or do you think jbweld will be good enough to hold the bearing.

The control sheave had a void as received from PO. It was still 'operational' although I barely put any time on it.

If the jbweld fails, I will likely try to reinforce it with a sleeve. This being a weak link will mean religious lubrication will be mandatory(not a bad idea anyway!).

Time will tell.

I fear Bill is being a prophet!:eek:

In case you are not aware ofthis.