Vise to Hold Gearbox?

nomadwarmachine · Dec 21, 2012

What size bench vise have others used to hold the Commando gearbox when rebuilding it? I would think that a 6" vise is sufficient, but I wanted to check with others who had actually done the business. Should not matter much, but this is for a 1974 Commando M2a.

Hobot · Dec 21, 2012

Yep my 6" vice holds the shell fine for me. Extra handy to have very tough leather sections to cushion various items but not needed for gear box or crank cases.

acotrel · Dec 21, 2012

I always have a couple of pieces of aluminium angle to cover the grips on the vise, so I don't get an imprint pressed into aluminium parts.

pete.v · Dec 21, 2012

I have a rolling bench with a 3/4" plywood top. I put a big hole in one corner so the main shaft could stink down. Piece of cake.

No real need to clamp up for me.

79x100 · Dec 21, 2012

A 5" Record bench vice is plenty big enough for Norton gearboxes which need about 3 1/2" opening. The box won't quite fit into my little 3" Record No.1 but anything bigger should be OK if it's firmly mounted.

Hobot · Dec 21, 2012

Oh yeah The Hole. I've a square stool for a bench seat with 2" wood plate on it and bored two holes of size-space that I can stand fork legs in or stick a shaft through to service or knock out.

bluto · Dec 21, 2012

a good excuse to buy a Jawhorse...I use mine for all sorts of MC work, most recently for working on forks on a couple of bikes, use it for tire changing too and to hold a work table...the jaws have rubber faces so they don't mar parts. Highly recommended, you can use both hands to position work and your foot to clamp the item.

nomadwarmachine · Dec 25, 2012

The Jawhorse is pretty cool! Going to start off with the bench vise and move from there. Want to get the gearbox rebuilt this winter.

Am I correct that I can remove the gearbox without having to remove the swingarm / destabilize the bike. Looks like it should just pop out once I disassemble the primary.

nomadwarmachine · Dec 25, 2012

Also, would a 4-inch vise work, or is that too small?

BillT · Dec 25, 2012

nomadwarmachine said:
Also, would a 4-inch vise work, or is that too small?

If the jaws will open at least 3 1/2" it should work. As others have said, using something to cushion the jaws will keep them from marking up the transmission case. I have a 6" vise and took some 16 gage aluminum shaped to wrap around the jaws. Anytime I put something in I don't want to mark up, I slip the aluminum pieces in. I've worn out my first set and made another (aluminum is softer than just about anything else I clamp in the vise and they get beat up)

There are vises with replaceable jaw edges (serrated, smooth, brass, lead, fiber, etc.), but I find just using the basic serrated jaws with the slip-on aluminum caps cover just about every use.

Hobot · Dec 25, 2012

Only need to spread jaws a bit less than 3.5" to grip the flats of the bottom bosses.
Main issue would be narrower jaw edges to mare the bosses a bit, but not much loading to un do or do up AMC kit. Just don't expect 4" vice to hold up for a stuck up caliper cap or beating a bend muffler hanger back nicer. It should be able to hold crank cases upright to diddle most of it too but maybe final full torque on everything which can be done mounted about as easy and secure.

gripper · Dec 25, 2012

After you have removed the primary cases, you will find the gearbox can be removed to the righthand side, but only after you have removed the three forward cradle bolts and swiveled the cradle to the rear. This moves the cradle and uncovers the cutout in the RH side that is normally covered by the engine. You can do it with a 22t gearbox sprocket fitted but easier with the sprocket removed. When looking at the RH side twist the gearbox anti clockwise till the casing lines up with the elongations in the plate. Best of British :wink:

Hobot · Dec 25, 2012

On the 750's other than the combat i just un do primary side then un bolt the grearbox and then tip gear box forward to align with cuts outs. On Combat with low down breather baffle in the way I've un done the 3 cradle bolts and headers and coil pack to tip engine forward, but like the cradle tip back labor saver idea.

nomadwarmachine · Dec 26, 2012

gripper said:
After you have removed the primary cases, you will find the gearbox can be removed to the righthand side, but only after you have removed the three forward cradle bolts and swiveled the cradle to the rear. This moves the cradle and uncovers the cutout in the RH side that is normally covered by the engine. You can do it with a 22t gearbox sprocket fitted but easier with the sprocket removed. When looking at the RH side twist the gearbox anti clockwise till the casing lines up with the elongations in the plate. Best of British :wink:

Perfect! Will post photos of the progress/regress!

nomadwarmachine · Dec 26, 2012

Found the old vise I had to build R/C planes in my childhood. It opens to 4 1/2" and is not top-of-the-line by any measure, but it has sentimental value, so it looks like I will use that.

Hobot · Dec 27, 2012

Handier to mount on a corner than mid bench or in my case old '1930s wood desk.

Vise to Hold Gearbox?

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