Pete,
I am in the middle of a Glider G4 rebuild and am thinking it would be a good time to make the change from picas to inches. I looked at your thread from ought six, http://www.machinejunkie.com/forum/viewtopic.php?t=178 and like the idea of replacing the lead screw and nut as well as the scale.
Before I dive into it, I have some questions and hope you can share some insights with me.
Now that you have 4+ years of experience with this mod, does it work as you expected? Would you recommend it to others?
Why did you go with 8 TPI Acme rather than 16 TPI Acme - I am guessing it was availability?
I am thinking I would make a new point dial as well, with either 8 or 16 indents in it. With 8 TPI Acme rod, this would make each indent 1/64" or 1/128" respectively. Any thoughts on this?
I read that your first try at the finger nut did not work out, wondering if you can recall what the problem with it was?
Cheers!
Dan
Pica to Inch
Moderator: crzypete
I consider the upgrade essential. It has been a great addition to my work flow and woodworking life. I ended up converting both of my G100's which are my daily drivers.
I have no regrets to the choices I made. I am not sure you can even get 16 tpi acme, but even if you could, I am not thinking it would be an advantage, the 8tpi leadscrew is plenty accurate, and I would think a fine thread like 16 tpi might not mesh as easily or consistently. Also, I would get annoyed at how slowly it advanced when rotating the knob.
BTW, remember that it is a left-handed thread- just a reminder for your planning.
The indexing dial works as follows
1 turn is 1/8"
turn to 6 it moves 1/16"
turn to 3 it moves 1/32"
turn to 1.5 it moves 1/64"
In my work flow I sometimes use it to cut 16ths, but once I get beyond that, I am just cutting to make a part fit, ignoring the dial.
If I were to make a dial it would be indented on 8 spots, with lines in the middle so you could stop it half way to get a finer increment. 16 indents would be too slow and probably less positive. That being said, I have absolutely no plans on remaking the knob.
The first failure was a geometry issue. I didn't get the alignment quite right and it didn;t fully mesh. It turns out the G100 is slightly different than the G4 so it is actually two sets of measurements to figure out. I think I have the G100 down now, but haven;t done many G4's since.
Keep us posted on your upgrade, it will be fun to follow along.
Pete
I have no regrets to the choices I made. I am not sure you can even get 16 tpi acme, but even if you could, I am not thinking it would be an advantage, the 8tpi leadscrew is plenty accurate, and I would think a fine thread like 16 tpi might not mesh as easily or consistently. Also, I would get annoyed at how slowly it advanced when rotating the knob.
BTW, remember that it is a left-handed thread- just a reminder for your planning.
The indexing dial works as follows
1 turn is 1/8"
turn to 6 it moves 1/16"
turn to 3 it moves 1/32"
turn to 1.5 it moves 1/64"
In my work flow I sometimes use it to cut 16ths, but once I get beyond that, I am just cutting to make a part fit, ignoring the dial.
If I were to make a dial it would be indented on 8 spots, with lines in the middle so you could stop it half way to get a finer increment. 16 indents would be too slow and probably less positive. That being said, I have absolutely no plans on remaking the knob.
The first failure was a geometry issue. I didn't get the alignment quite right and it didn;t fully mesh. It turns out the G100 is slightly different than the G4 so it is actually two sets of measurements to figure out. I think I have the G100 down now, but haven;t done many G4's since.
Keep us posted on your upgrade, it will be fun to follow along.
Pete
I was thinking more about this today, and remembered the one thing that I found very important after my first conversion- making sure the ruler is as perfectly aligned to the blade as possible in terms of accurate measuring. This has nothing to do with the accuracy of the fingerscale, but everything to do with using the ruler without the fingerscale.
One of my favorite tricks is to hook a tape measure to the end of a board that is too long to use the hammond ruler with, then I line up an inch shorter than I want to cut on the tape measure with the one inch mark on the ruler. this is quick and pretty damn accurate, but it definitely requires the ruler be accurate to the blade.
Pete
One of my favorite tricks is to hook a tape measure to the end of a board that is too long to use the hammond ruler with, then I line up an inch shorter than I want to cut on the tape measure with the one inch mark on the ruler. this is quick and pretty damn accurate, but it definitely requires the ruler be accurate to the blade.
Pete
Last edited by crzypete on Sun Sep 05, 2010 9:36 am, edited 1 time in total.
Thanks Pete. I was wondering about this a bit.
Doesn't it depend on the sawblade you use too? If you switch to a different kerf thickness blade it will screw up the absolute value of the measurements? on the other hand, if you are only working to 1/16" normally, then the small amount of a different kerf thickness will probably not matter.
In any case, I think I understand what you are saying and will be careful to make sure the ruler zero aligns with the edge of the blade tooth.
I am going to reassemble my Glider with the original ruler first, then I will make the conversion to inches. Everything(*) is out at the shop being powder coated now, should be ready mid next week for re-assembly to start.
(*) Everything that needs to be powder coated that is! They will mask off stuff that should not get paint on it, and some parts will not be painted at all.
Dan
Doesn't it depend on the sawblade you use too? If you switch to a different kerf thickness blade it will screw up the absolute value of the measurements? on the other hand, if you are only working to 1/16" normally, then the small amount of a different kerf thickness will probably not matter.
In any case, I think I understand what you are saying and will be careful to make sure the ruler zero aligns with the edge of the blade tooth.
I am going to reassemble my Glider with the original ruler first, then I will make the conversion to inches. Everything(*) is out at the shop being powder coated now, should be ready mid next week for re-assembly to start.
(*) Everything that needs to be powder coated that is! They will mask off stuff that should not get paint on it, and some parts will not be painted at all.
Dan
Dan, I should clarify my 1/16's statement. I work way tighter than 1/16's. I just find I do not measure beyond 1/16's with the fingerscale. It is crucial for my work that when it is set to a number it is dead-nuts. I use digital calipers to adjust the saw to cut within a thousandth or two. (I could pull out a micrometer, but at the end of the day, I do understand that it is wood I am dealing with.
The ruler has to be set for the blade you plan on using on most days in order to be accurate. I run Forrest blades for all of my woodworking. When I switch to a thinner blade, the accuracy is gone and the whole system is pretty worthless.
If you ever want to change to a thinner blade for a more permanent capacity, you can actually change the positioning of the blade in the housing which holds the bearings for the arbor. It is designed with threaded rings on either side that allow you to shift the position of the blade assembly. As long as you stay within the allotted kerf for the blade, you have some flexibility, especially when you start running very thin blades.
To confirm, you are understanding what I am saying about the zero point aligning with the edge of the blade.
Pete
The ruler has to be set for the blade you plan on using on most days in order to be accurate. I run Forrest blades for all of my woodworking. When I switch to a thinner blade, the accuracy is gone and the whole system is pretty worthless.
If you ever want to change to a thinner blade for a more permanent capacity, you can actually change the positioning of the blade in the housing which holds the bearings for the arbor. It is designed with threaded rings on either side that allow you to shift the position of the blade assembly. As long as you stay within the allotted kerf for the blade, you have some flexibility, especially when you start running very thin blades.
To confirm, you are understanding what I am saying about the zero point aligning with the edge of the blade.
Pete
Dan,
I am not sure about your plans for blade size, but I find that I would not want a larger blade than a 7 1/4" with the standard hammond mounting screws. Beyond that, I think an arbor is in order.
I run a saw that has been converted to an arbor (8 1/2" blade), and an original hammond configured one (7 1/4" blade) and find both quite useful.
Pete
I am not sure about your plans for blade size, but I find that I would not want a larger blade than a 7 1/4" with the standard hammond mounting screws. Beyond that, I think an arbor is in order.
I run a saw that has been converted to an arbor (8 1/2" blade), and an original hammond configured one (7 1/4" blade) and find both quite useful.
Pete
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nowhere man
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Pete,
I'm starting the reassembly process, and I'm wondering about the reassembly of the finger nut into the finger. It appears that the finger nut rides on a shaft and is "pinned" in place by a couple of Allen screws. One of the Allen screws is called an "adjusting screw" in the G4 Parts and Supply Manual G952.
That got me thinking that by using these two Allen screws one could adjust the position of the finger nut relative to the finger itself, and thus to the scale? Does this mean that there is actually a little wiggle room when the time comes to replace the ruler, if it's out a smidgeon you can correct it by adjusting the finger nut position?
Dan
I'm starting the reassembly process, and I'm wondering about the reassembly of the finger nut into the finger. It appears that the finger nut rides on a shaft and is "pinned" in place by a couple of Allen screws. One of the Allen screws is called an "adjusting screw" in the G4 Parts and Supply Manual G952.
That got me thinking that by using these two Allen screws one could adjust the position of the finger nut relative to the finger itself, and thus to the scale? Does this mean that there is actually a little wiggle room when the time comes to replace the ruler, if it's out a smidgeon you can correct it by adjusting the finger nut position?
Dan
Dan, It is very adjustable and you can move the fingerscale all over the place and it will still be accurate. This was my initial thinking when I only half accurately placed the rule.
The problem is, I really like to use the ruler without the fingerscale, and in order to do this, it's got to be spot on.
Pete
The problem is, I really like to use the ruler without the fingerscale, and in order to do this, it's got to be spot on.
Pete