# Bushings and bits



## GEORGE6149 (Dec 3, 2004)

Is there a way to be able to easily figure out where a cut will be by using bushings? EXAMPLE, If you were using a 3/4 bushing and a 1/4 bit,would it be around 7/8 from workpiece to end of cut. Thanks


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## challagan (Feb 7, 2006)

GEORGE6149 said:


> Is there a way to be able to easily figure out where a cut will be by using bushings? EXAMPLE, If you were using a 3/4 bushing and a 1/4 bit,would it be around 7/8 from workpiece to end of cut. Thanks


George I think it would be the outside diameter of the bushing plus the difference in the inside diameter of bushing and the diameter of the bit. So 3/4 +( 1/4 (bit) - ___ (inside Diam of bushing) = distance 

One of the template guys will let's us know if this is right or if I am full of it!

Corey


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## bobj3 (Jan 17, 2006)

Hi George6149

Here's a chart that may help. 

Bj


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## challagan (Feb 7, 2006)

bobj3 said:


> Hi George6149
> 
> Here's a chart that may help.
> 
> Bj


Great chart Bj, I saved it. So what I posted is correct?

Corey


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## bobj3 (Jan 17, 2006)

Outside

(inside Diam of bushing) = distance

Bj


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## GEORGE6149 (Dec 3, 2004)

Thanks everyone. The chart is great. My question has been answered.


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## curiousgeorge (Nov 6, 2006)

Thanks for the chart Bj. I have been trying to make a template and keep messing up on the measurements. Maybe I can get it right now.


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## bobj3 (Jan 17, 2006)

You'er Welcome George

This item was made by " Ed " ( forum member name of "reible" ) and he did a great job making it up.

Bj


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## template tom (Sep 18, 2004)

challagan said:


> George I think it would be the outside diameter of the bushing plus the difference in the inside diameter of bushing and the diameter of the bit. So 3/4 +( 1/4 (bit) - ___ (inside Diam of bushing) = distance
> 
> One of the template guys will let's us know if this is right or if I am full of it!
> 
> Corey


*Corey
There is no need to measure the inside diameter of the guide. The only concern is will the cutter fit through it ok
Tom*


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## template tom (Sep 18, 2004)

bobj3 said:


> Outside
> 
> (inside Diam of bushing) = distance
> 
> Bj


*Bob
Unable to ascertain what you are trying to say here with this posting.
Tom*


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## template tom (Sep 18, 2004)

GEORGE6149 said:


> Is there a way to be able to easily figure out where a cut will be by using bushings? EXAMPLE, If you were using a 3/4 bushing and a 1/4 bit,would it be around 7/8 from workpiece to end of cut. Thanks


*George
I hope I understand your question. Correct me if I am wrong 

You wish to know what size of cut-out required in a template. This will be determined by the template guide and cutter combination to be used and of course the size of the project cut-out.

If the size of the material cut out say is 8" x 4" and we are using a 3/4" Guide and a 1/4" cutter.

The size of the template cut-out required would be 8-1/2" x 4-1/2"
I hope this answers your question

Tom  *


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## challagan (Feb 7, 2006)

template tom said:


> *Corey
> There is no need to measure the inside diameter of the guide. The only concern is will the cutter fit through it ok
> Tom*


Thanks Tom, I understand now. I think that is what Bob was trying to tell me as well. 

Corey


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## curiousgeorge (Nov 6, 2006)

If I am reading all this correctly the formula to figure the offset would be:

1/2 x (bushing OD - bit size) = offset

Then take the offset, double it and add this to the dimensions of the desired opening. Is this correct? :'(


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## harrysin (Jan 15, 2007)

*calculating template offset*

Tom, whilst I wouldn't attempt to argue with you're answer, which is of course correct, if during lessons with you I had only received answers and not been taught how to do the calculations I would be in a very sorry state. Isn't it simple to just state that guide radius plus cutter radius equals offset?
In the case in question for a finished project measuring 8" x 4" using a 0.75" guide and a 0.25" cutter: 0.375" + 0.125" = 0.5" ie: cut-out is 0.5" bigger than the project or as Tom has stated 8.5" x 4.5"


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## template tom (Sep 18, 2004)

harrysin said:


> Tom, whilst I wouldn't attempt to argue with you're answer, which is of course correct, if during lessons with you I had only received answers and not been taught how to do the calculations I would be in a very sorry state. Isn't it simple to just state that guide radius* plus* cutter radius equals offset?
> In the case in question for a finished project measuring 8" x 4" using a 0.75" guide and a 0.25" cutter: 0.375" + 0.125" = 0.5" ie: cut-out is 0.5" bigger than the project or as Tom has stated 8.5" x 4.5"


*Harry
I am sure you did mean minus instead of plus
Tom*


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## template tom (Sep 18, 2004)

curiousgeorge said:


> If I am reading all this correctly the formula to figure the offset would be:
> 
> 1/2 x (bushing OD - bit size) = offset
> 
> Then take the offset, double it and add this to the dimensions of the desired opening. Is this correct? :'(



*Correct*
Tom


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## harrysin (Jan 15, 2007)

*Semantics regarding "off-set"*

Hi Tom, no, I did not mean minus, but, I must apologise for incorrect terminology, 
the results from my formula give you the increase in the size of the cut-out compared to the finished size of the project, not the offset which would of course require the two figures to have a minus sign between them, I do hope that you will forgive this transgression, I shall attempt to do better in the future
you're former pupil Harry


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## curiousgeorge (Nov 6, 2006)

*Semantics, formulas, terminology?*

It looks like we are all getting the same place by going down different roads. The correct answer is what matters irregardless of the method. I am going to get this template thing down even if it hairlips the governor.  

It is good to have more than one way to accomplish a goal. I have found that some people will not understand one method or terminology, but when explained another way the light bulb will suddenly come on. By having more methods or different terminologies you have the potential of reaching more people and that is what this forum is all about. So keep it up Guys. Different is GOOD!


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