DavidB
Well-known member
I was working on my truck the other day and ran into the situation where the bolt moved with the ratchet in both directions. This is very annoying when you can't get your fingers on the bolt and have to go find another ratchet to finish getting the bolt out as you probably know. Folks here (and probably elsewhere) refer to the torque required to make a ratchet go backwards as back drag. Afterwards finishing up on the truck, I started looking more into the back drag of my ratchets. Picking them up and rotating them in my hand showed that some ratchets had better back drag than others. But I was curious to put numbers on them because I'm wired that way.
So, I present the results of my low tech method of measuring ratchet back drag. To measure the back drag I needed a way of slowly increasing torque on the ratchet to see when it moved. I scratched my head for a little bit and came up with the plan to put a bar on a ratchet, hang a cup off the bar, and slowly add weight to the cup until it dropped.
Here's a pic of my low tech setup with a 3/8" drive ratchet:
Nit picking details (skip if wanted):
The bar is mounted on the ratchet in the middle so as not to contribute to the weight trying to turn the ratchet. There's also small notches in the bar to keep the string in the same spot each time. I filed the end of the bars down so that it balanced at the middle of the square where the ratchet fit. I used a funnel and my finger to slowly meter out aluminum oxide blast media. When the cup dropped onto the scale I disconnected the string and took a reading off the scale. There's a short delay between the cup dropping and when I stop the flow of media. The media comes out slow enough for it not to change the reading on the scale though from my testing to by adding media to a cup sitting on the scale. There was sometimes movement in the cup before it dropped but I kept adding media until it dropped completely.
My scale is an old postal meter that measures in 0.1oz increments. I don't have it calibrated since it just use it around the house. Instead I used a series of coins as test weights because they should be close to their weights listed from the US mint. Weighing the coins showed that my scale always rounds up to the next 0.1 oz when the weight is above 0.01 oz. The results of the scale always matched the theoretical combined weight of the coins when rounding this way which leads me to believe my weight measuring error to be 0 oz to +0.1oz.
When measuring the 1/4" drive ratchets I used a 2" moment arm and for the 3/8" drive ratchets I used a 5" moment arm. I used a different bar for the different ratchet drive sizes. So, my back drag torque values hopefully have a max error of 0.2 in-oz for the 1/4" drive ratchets and 0.5 in-oz for the 3/8" drive ratchets.
1/4" Drive Results:
I took three measurements per ratchet, averaged the weights, and multiplied by the arm to get the back drag torque values shown in the right most column.
1/4" Drive ratchets:
Here are the ratchets. Their order in the pic does NOT match the order in the table.
3/8" Drive Results:
I took four measurements per ratchet, averaged the weight values, and multiplied by the arm to get the back drag torque values shown in the right most column.
3/8" Drive Ratchets:
Once again, order does NOT match the table.
Note I'm a DIY guy so I'm going to say all my use is light to moderate use compared to a pro using tools everyday. I can't say how much the ratchets were used before I bought them as I buy used a lot. If I've changed the lube out I say what with. Otherwise I assume factory lubed.
Some info on the 1/4" ratchets...
Benchtop - Made in Taiwan ratchet out of a set that rides around in my car. I've probably used it only a few times. It has the lowest back drag but feels loose in a bad way and occasionally a tooth when moving the ratchet quickly. Factory lubed.
Gearwrench 81028 - Borrowed from a friend. New.
Snap-On TL72 - I bought it lightly used off of Ebay. I'm a DIY guy so its still lightly used. Factory lubed.
Snap-On T72 - Bought off Ebay recently and is almost brand new. Factory lubed.
Craftsman old Raised Panel - Older Craftsman ratchet from my grandfather that is marked -V-. It has an oil ball on the top of the ratchet and I use hydraulic oil to lubricate it.
Snap-On TML70A - I found it at a flea market and it looks like it's been well used. Lubricated with Super-Lube.
Snap-On T936 - I purchased it used off of Ebay. I played around with lubricants to see the effects. WB Grease is Mobil wheel bearing grease. SL is Super Lube. Oil is hydraulic oil. Dry is what I got wiping the internal parts down with a paper towel until it looked dry.
Wright 2492 - Purchased new and lightly used because I'm not a fan of the coarse gearing and high back drag. Lubed with hydraulic oil.
Some info about the 3/8" ratchets:
Proto 5249 - Another flea market find. I think I used the wheel bearing grease in it a while back after cleaning it out. It's in good shape but mostly gets used with my mill due to the coarse teeth and large head.
CM 43175 - Round head fine tooth Craftsman ratchet. Another flea market find in really good shape. Factory lubed.
New Britain NB-45 - Antique store find. In like new condition. Factory lubed.
SK 45170 - Flea market find and in good shape with SK logo in the diamond. Factory lubed.
GW 81264 - Bought new. Lightly used. Factory lubed.
Snap-On F80 - Bought off eBay lightly used. Seen DIY use since then.
Craftsman newer RP - Craftsman made in USA marked -VQ-. Bought new with a socket set I think. Not sure I've ever used it. Factory lube.
Snap-On F723 - Bought at a flea market. Well used. Lubed with Super Lube.
CM old RP - Another old raised panel ratchet from my grandfather. Marked =V= with the oil port. Lubed with hydraulic oil.
Wright 3490 - Bought new and very lightly used. Oiled with hydraulic oil.
Snap-On F936 - Bought used on ebay. Light use from me. Lubed with Super Lube.
The don't flame me or argue about the best ratchet bit:
These are simple results based on a few tests with my handful of ratchets in various condition. I imagine ratchet use would reduce the back drag due to wear and fatigue on the spring. The value of a ratchet in the user's mind is a result of multiple features. In other words, I'm not saying X ratchet is better than Y. I'm just showing what I found.
Well, except for one....
I was disappointed with the back drag on the Snap-On F936 especially compared to the much older ratchets. So, I decided to do something about it. Here's the guts of the F936.
My thoughts are that back drag is primarily caused by friction between the pawl (the bat shaped part) and the gear. If you look closely between the pawl and ratchet head you'll see a small ball. This ball is forced against the pawl by a spring in the ratchet head that isn't shown. The gear and pawl teeth slide on each other until the pawl drops to the next tooth. Friction between these two is a result of the surface finish on the parts and the force the pawl puts on the gear. Surface finish could be improved but I don't think there's much to gain here. You can reduce the force the pawl exerts though by modifying the spring. That's where I'm focusing my efforts.
Note: If you try this be aware that when you remove the pawl the spring will launch the ball into orbit if you're not careful. The spring may follow after it too. When you go to put the ball and spring back it's easy to launch them again. So, be careful and disassemble it in a ziplock bag the first few times. The ball and spring are very tough to find on the floor.
I didn't want to cut down my stock spring in the F936 because I didn't want to make my ratchet useless if I screwed up and cut too much off. I went looking for a replacement spring at a local hardware store but didn't find anything small enough. So, I started looking into pens and mechanical pencils. I found a few around my house and borrowed a few from work to sample. The stock spring is about 0.155" in diameter and most of the pens I found had springs that are a bit larger. I did find a beat up pen in my garage and a mechanical pencil that had small enough springs. See here:
Here are the sprigs from the pen and pencil above. I stuck two images together because I used the pen spring first and then found I couldn't find a name on the pen. The mechanical pencil is a Zebra M-301. In the pic below: Stock is the spring the F936 came with. MP is the mechanical pencil spring. I cut down my replacement springs and will discuss that below.
Here's the results:
Everything was lubed with Super Lube.
SO F936 - Stock spring in place.
SO F936 Pen Spring C - The coils on the end of the pen's spring are really close together. When I tried the uncut spring the ball wouldn't go below the opening hole meaning I couldn't get the pawl in. So, I cut the close together coils section off one end as close to the close together coils as I could.
SO F936 MP Spring S - This is the spring from the mechanical pencil uncut.
SO F936 MP Spring C1 - I cut on end of the spring off right below where the coils were close together.
SO F936 MP Spring C2 - After C1 I removed another full turn of the coil.
I stopped at this point though I probably could have cut a bit more (maybe another full turn) off the spring. I didn't want to cut the spring too short for fear that it might lead to the ratchet skipping. I've gone back to the pen spring and am going to try it out.
Modding the spring is something others have suggested here but I hope I've quantified the results a bit. It definitely improves the feel of the F936 and you might want to give it a try if the back drag bothers you.
I think you could cut down the spring in any pear headed ratchet but I've not looked into modding a round headed ratchet. Besides the round headed ratchets seemed to already have low back drag. Also, I don't have any RLL but I'm sure I could find some if there's a large outcry. I'd test measure other ratchets but ratchets can be pricey and it's hard to argue I need another one to myself.
So, lube those ratchets and cut down springs to live the good low back drag life!
Just don't over do it.
So, I present the results of my low tech method of measuring ratchet back drag. To measure the back drag I needed a way of slowly increasing torque on the ratchet to see when it moved. I scratched my head for a little bit and came up with the plan to put a bar on a ratchet, hang a cup off the bar, and slowly add weight to the cup until it dropped.
Here's a pic of my low tech setup with a 3/8" drive ratchet:
Nit picking details (skip if wanted):
The bar is mounted on the ratchet in the middle so as not to contribute to the weight trying to turn the ratchet. There's also small notches in the bar to keep the string in the same spot each time. I filed the end of the bars down so that it balanced at the middle of the square where the ratchet fit. I used a funnel and my finger to slowly meter out aluminum oxide blast media. When the cup dropped onto the scale I disconnected the string and took a reading off the scale. There's a short delay between the cup dropping and when I stop the flow of media. The media comes out slow enough for it not to change the reading on the scale though from my testing to by adding media to a cup sitting on the scale. There was sometimes movement in the cup before it dropped but I kept adding media until it dropped completely.
My scale is an old postal meter that measures in 0.1oz increments. I don't have it calibrated since it just use it around the house. Instead I used a series of coins as test weights because they should be close to their weights listed from the US mint. Weighing the coins showed that my scale always rounds up to the next 0.1 oz when the weight is above 0.01 oz. The results of the scale always matched the theoretical combined weight of the coins when rounding this way which leads me to believe my weight measuring error to be 0 oz to +0.1oz.
When measuring the 1/4" drive ratchets I used a 2" moment arm and for the 3/8" drive ratchets I used a 5" moment arm. I used a different bar for the different ratchet drive sizes. So, my back drag torque values hopefully have a max error of 0.2 in-oz for the 1/4" drive ratchets and 0.5 in-oz for the 3/8" drive ratchets.
1/4" Drive Results:
I took three measurements per ratchet, averaged the weights, and multiplied by the arm to get the back drag torque values shown in the right most column.
1/4" Drive ratchets:
Here are the ratchets. Their order in the pic does NOT match the order in the table.
3/8" Drive Results:
I took four measurements per ratchet, averaged the weight values, and multiplied by the arm to get the back drag torque values shown in the right most column.
3/8" Drive Ratchets:
Once again, order does NOT match the table.
Note I'm a DIY guy so I'm going to say all my use is light to moderate use compared to a pro using tools everyday. I can't say how much the ratchets were used before I bought them as I buy used a lot. If I've changed the lube out I say what with. Otherwise I assume factory lubed.
Some info on the 1/4" ratchets...
Benchtop - Made in Taiwan ratchet out of a set that rides around in my car. I've probably used it only a few times. It has the lowest back drag but feels loose in a bad way and occasionally a tooth when moving the ratchet quickly. Factory lubed.
Gearwrench 81028 - Borrowed from a friend. New.
Snap-On TL72 - I bought it lightly used off of Ebay. I'm a DIY guy so its still lightly used. Factory lubed.
Snap-On T72 - Bought off Ebay recently and is almost brand new. Factory lubed.
Craftsman old Raised Panel - Older Craftsman ratchet from my grandfather that is marked -V-. It has an oil ball on the top of the ratchet and I use hydraulic oil to lubricate it.
Snap-On TML70A - I found it at a flea market and it looks like it's been well used. Lubricated with Super-Lube.
Snap-On T936 - I purchased it used off of Ebay. I played around with lubricants to see the effects. WB Grease is Mobil wheel bearing grease. SL is Super Lube. Oil is hydraulic oil. Dry is what I got wiping the internal parts down with a paper towel until it looked dry.
Wright 2492 - Purchased new and lightly used because I'm not a fan of the coarse gearing and high back drag. Lubed with hydraulic oil.
Some info about the 3/8" ratchets:
Proto 5249 - Another flea market find. I think I used the wheel bearing grease in it a while back after cleaning it out. It's in good shape but mostly gets used with my mill due to the coarse teeth and large head.
CM 43175 - Round head fine tooth Craftsman ratchet. Another flea market find in really good shape. Factory lubed.
New Britain NB-45 - Antique store find. In like new condition. Factory lubed.
SK 45170 - Flea market find and in good shape with SK logo in the diamond. Factory lubed.
GW 81264 - Bought new. Lightly used. Factory lubed.
Snap-On F80 - Bought off eBay lightly used. Seen DIY use since then.
Craftsman newer RP - Craftsman made in USA marked -VQ-. Bought new with a socket set I think. Not sure I've ever used it. Factory lube.
Snap-On F723 - Bought at a flea market. Well used. Lubed with Super Lube.
CM old RP - Another old raised panel ratchet from my grandfather. Marked =V= with the oil port. Lubed with hydraulic oil.
Wright 3490 - Bought new and very lightly used. Oiled with hydraulic oil.
Snap-On F936 - Bought used on ebay. Light use from me. Lubed with Super Lube.
The don't flame me or argue about the best ratchet bit:
These are simple results based on a few tests with my handful of ratchets in various condition. I imagine ratchet use would reduce the back drag due to wear and fatigue on the spring. The value of a ratchet in the user's mind is a result of multiple features. In other words, I'm not saying X ratchet is better than Y. I'm just showing what I found.
Well, except for one....
I was disappointed with the back drag on the Snap-On F936 especially compared to the much older ratchets. So, I decided to do something about it. Here's the guts of the F936.
My thoughts are that back drag is primarily caused by friction between the pawl (the bat shaped part) and the gear. If you look closely between the pawl and ratchet head you'll see a small ball. This ball is forced against the pawl by a spring in the ratchet head that isn't shown. The gear and pawl teeth slide on each other until the pawl drops to the next tooth. Friction between these two is a result of the surface finish on the parts and the force the pawl puts on the gear. Surface finish could be improved but I don't think there's much to gain here. You can reduce the force the pawl exerts though by modifying the spring. That's where I'm focusing my efforts.
Note: If you try this be aware that when you remove the pawl the spring will launch the ball into orbit if you're not careful. The spring may follow after it too. When you go to put the ball and spring back it's easy to launch them again. So, be careful and disassemble it in a ziplock bag the first few times. The ball and spring are very tough to find on the floor.
I didn't want to cut down my stock spring in the F936 because I didn't want to make my ratchet useless if I screwed up and cut too much off. I went looking for a replacement spring at a local hardware store but didn't find anything small enough. So, I started looking into pens and mechanical pencils. I found a few around my house and borrowed a few from work to sample. The stock spring is about 0.155" in diameter and most of the pens I found had springs that are a bit larger. I did find a beat up pen in my garage and a mechanical pencil that had small enough springs. See here:
Here are the sprigs from the pen and pencil above. I stuck two images together because I used the pen spring first and then found I couldn't find a name on the pen. The mechanical pencil is a Zebra M-301. In the pic below: Stock is the spring the F936 came with. MP is the mechanical pencil spring. I cut down my replacement springs and will discuss that below.
Here's the results:
Everything was lubed with Super Lube.
SO F936 - Stock spring in place.
SO F936 Pen Spring C - The coils on the end of the pen's spring are really close together. When I tried the uncut spring the ball wouldn't go below the opening hole meaning I couldn't get the pawl in. So, I cut the close together coils section off one end as close to the close together coils as I could.
SO F936 MP Spring S - This is the spring from the mechanical pencil uncut.
SO F936 MP Spring C1 - I cut on end of the spring off right below where the coils were close together.
SO F936 MP Spring C2 - After C1 I removed another full turn of the coil.
I stopped at this point though I probably could have cut a bit more (maybe another full turn) off the spring. I didn't want to cut the spring too short for fear that it might lead to the ratchet skipping. I've gone back to the pen spring and am going to try it out.
Modding the spring is something others have suggested here but I hope I've quantified the results a bit. It definitely improves the feel of the F936 and you might want to give it a try if the back drag bothers you.
I think you could cut down the spring in any pear headed ratchet but I've not looked into modding a round headed ratchet. Besides the round headed ratchets seemed to already have low back drag. Also, I don't have any RLL but I'm sure I could find some if there's a large outcry. I'd test measure other ratchets but ratchets can be pricey and it's hard to argue I need another one to myself.
So, lube those ratchets and cut down springs to live the good low back drag life!
Just don't over do it.
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