# Bench Dog Pro Plate and Zero Clearance Insert problem



## matt1710 (Sep 21, 2010)

I'm having real trouble getting my Bench Dog Pro Plate and Bench Dog Zero clearance ring to work with my Makita 3612C. I've been in contact with BenchDog several times, however they haven't provided a solution. 

The issue is that once the zero clearance insert is attached to the 2" reduction ring (which is bolted into the pro plate), the flange on the underside of the zero clearance ring bumps into the router's base (subbase removed of course!) and prevents the router's base sitting flush with the underside of the pro plate. 

I took some measurements with my digital calipers:

• external diameter of flange of zero clearance insert : 76.21mm, 3"
• maximum diameter of aperture in router's base : 68mm, 2 2/3"
• minimum diameter of aperture in router's base : 62.11mm, 2.5" 

The reason for there being two measurements for the diameter of the aperture in the router's base : there are two 'tabs' into which template collars screw when they're in use. These two 'tabs' sit opposite each other, and reduce the diameter of the aperture at that point. Even if those tabs weren't there, the flange of the zero clearance ring is still too large to fit into the aperture of the router's base.

As I see it, there's no way that the zero clearance insert can attach to the 2" reduction ring and permit the router base to sit flush on the underside of the pro plate. If the nuts of the bolts used to secure the insert are installed, the situation is even worse. 

As you can see from the diagram, the dotted lines represent the aperture in the router's base - and the flange is of greater diameter than this aperture. I assume the flange is supposed to be of lesser diameter than this aperture - which would allow the flange and nuts to sit in the aperture, and not hinder the router's base from sitting flush with the underside of the pro plate? If this assumption is incorrect, how is one supposed to get the router base and pro plate to sit flush? I was under the impression that the Makita 3612C has a large aperture in the base - how on earth would this flange go with router's that have a smaller aperture!!

I'm unable to cut the flange down as in order for it to sit within the aperture in the router's base, I'd have to cut so much off it, that the 3 holes that secure it would be removed too. 

I'd really like to find a solution to this as I really need to reduce the aperture of the 2" ring for safety reasons -there's simply too much space around the bit when using a 1/2" bit, for example. 

Matthew


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## Mike (Nov 22, 2004)

Matthew, the only easy solution is to shim the router to allow the clearance needed. I suggest using the routers sub base plate as a template to create a ring shim. The thickness of the shim should not interfere with the routers function in any way; you can always use a bit extender if you need more height for your bit.


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## matt1710 (Sep 21, 2010)

Hi Mike

Thanks for the solution. I had considered that, however was concerned about just how much bit height I'd loose, given the fact that the shim would need to be quite thick in order to allow the nuts that secure the zero clearance insert, to remain clear of the router base. 

It seems strange that Bench Dog (who I think have a good reputation - the Pro Plate is certainly very good) would create a zero clearance kit that has this issue. Perhaps it's just an issue with my particular router? As mentioned above though, the only way I can see it functioning is for the flange of the zero ring to sit inside the router base's aperture - and given that the 3612C has a large aperture....

Matthew


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## Mike (Nov 22, 2004)

Since the 3612C is discontinued I almost bought one... $164 was hard to pass up for such a great router. One other thing you might try Matthew, countersinking the screw holes and using flat head screws should give you a bit more clearance.


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## jschaben (Jun 21, 2009)

matt1710 said:


> Hi Mike
> 
> Thanks for the solution. I had considered that, however was concerned about just how much bit height I'd loose, given the fact that the shim would need to be quite thick in order to allow the nuts that secure the zero clearance insert, to remain clear of the router base.
> 
> ...


Hi Matt - I probably don't really understand the situation. The Bench Dog plate that Rockler sells appears to have a insert that takes on PC guide bushings. And it looks to be installed from the top. From there, several places have reducer inserts that will get you to zero or near zero clearance. Here's a set from Lee Valley.
1-3/16" Router Plate Inserts - Lee Valley Tools

I guess I can't get my head wrapped around why they would have something like that installed from the bottom. I would think it would be coming in and out on a regular basis.


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## matt1710 (Sep 21, 2010)

Mike said:


> Since the 3612C is discontinued I almost bought one... $164 was hard to pass up for such a great router.


Oh if I could buy another one for that money (even though that's US$, which is so weak at the moment!) I'd do it in a heartbeat. Would save me having to switch the router between table and handheld all the time.


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## matt1710 (Sep 21, 2010)

Hi John

Yes, now that you mention it, it seems strange that the zero clearance insert should be inserted from below the plate - meaning that the plate and the router need to be separated to install the Z.C.I. 

I've scanned the installation instructions and attached them here, if it helps you get your head around it? I'm hoping someone will propose a solution. So far, the shim is the only viable option. I can't recess the nuts into the Z.C.I. flange as there's not enough thickness there. Plus, even without the nuts, I can't get the Z.C.I. and router base to sit flush, as the combined thickness of Z.C.I. and 2" insert ring, is greater than the thickness of the plate. 

Matthew


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## matt1710 (Sep 21, 2010)

I bolted the 2" insert ring, and the zero clearance insert together, to see how thick a shim I'd need to clear the nut : 11mm. That's almost 1/2" - surely that's too much to loose from bit height? Although I guess it depends what I'm doing, and how much bit I need protruding...


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## jschaben (Jun 21, 2009)

matt1710 said:


> Hi John
> 
> Yes, now that you mention it, it seems strange that the zero clearance insert should be inserted from below the plate - meaning that the plate and the router need to be separated to install the Z.C.I.
> 
> ...


Hi Matt - OK, I see what they're doing. The ZCI is pretty much attached to the 2" insert ring and the assembly is thicker than the plate. Does Bench Dog make an insert ring that will accept guide bushings? With the number of different size bits I use, I'd need about a dozen of those assemblies. Actually, I did end up with a dozen inserts when all was said and done, 8 under 2". 1/2" is a lot of depth to loose, especially with some of the smaller bits which tend to be shorter. A collet extension may help in this circumstance but care would need to be taken not to hit the assembly with the retainer nut.
Good Luck.


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## matt1710 (Sep 21, 2010)

jschaben said:


> Hi Matt - OK, I see what they're doing. The ZCI is pretty much attached to the 2" insert ring and the assembly is thicker than the plate. Does Bench Dog make an insert ring that will accept guide bushings? With the number of different size bits I use, I'd need about a dozen of those assemblies. Actually, I did end up with a dozen inserts when all was said and done, 8 under 2". 1/2" is a lot of depth to loose, especially with some of the smaller bits which tend to be shorter. A collet extension may help in this circumstance but care would need to be taken not to hit the assembly with the retainer nut.
> Good Luck.


Bang on with your summation of the situation : 2" insert ring + ZCI = thicker than plate : by 11mm. 

Not sure re BenchDog making an insert ring that will accept guide bushings. Please tell me how such an insert would that help me to reduce the void around the bit - I'm new to this!

Matthew


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## jschaben (Jun 21, 2009)

matt1710 said:


> Bang on with your summation of the situation : 2" insert ring + ZCI = thicker than plate : by 11mm.
> 
> Not sure re BenchDog making an insert ring that will accept guide bushings. Please tell me how such an insert would that help me to reduce the void around the bit - I'm new to this!
> 
> Matthew


See the Lee Valley link I put in my last post. 
Instead of guide bushings, these things just fill the hole. Not exactly zero clearance, but close. The fly for you here is I think they are all in imperial. At least I'm not aware of any metric ones. :wacko:


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## jschaben (Jun 21, 2009)

Another suggestion. Looking at the installation .pdf, those inserts don't look awfully complicated. Could you make some inserts from hardboard or mdf and just drill center holes for the bits needed?


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## matt1710 (Sep 21, 2010)

Ah - now I get it re the Lee Valley inserts. I'll ask BenchDog if they make an insert ring that'll permit those to be added. They are designed to be added to a RT mounting plate - and not just a router's sub-base - right?

Re making my own MDF or hardboard ZCI - not a bad idea, however I think the problem still remains - how to secure it to the 2" insert ring - without making the setup thicker than the base plate. Even the proper BenchDog ZCI has a very thin flange (and that's too much) so can't see how I could make it thiner, and secure it properly. 

Maybe I need to ditch the BenchDog ZCI, and look at replacing the entire 2" ring with a custom made ring. That way, it'd install from the top, AND without needing to remove the router from the mounting plate. I guess the issue there will be getting stock the correct thickness so that it nestles down into the rebate in the mounting plate, yet doesn't protrude above the height of the surface of the mounting plate.


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## jschaben (Jun 21, 2009)

matt1710 said:


> Maybe I need to ditch the BenchDog ZCI, and look at replacing the entire 2" ring with a custom made ring. That way, it'd install from the top, AND without needing to remove the router from the mounting plate. I guess the issue there will be getting stock the correct thickness so that it nestles down into the rebate in the mounting plate, yet doesn't protrude above the height of the surface of the mounting plate.



Now yer talkin:sold:
That's what I had in mind. :yes4:
That way no worries over metric/imperial either.
If you have to settle for material a bit thinner, it's a pretty simple job to shim it up.


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## Mike (Nov 22, 2004)

Matt, see the sticky thread about making your own sub base plate and apply the information to your insert.


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## matt1710 (Sep 21, 2010)

Hi John / Mike

Thanks for the suggestions. As always, this forum and its members is a treasure trove of information for a newbie like me. I've read the sticky post re making a new sub-base - I think that's the way to go. I should be a very easy task given that I don't need the high degree of accuracy for the centre hole, as there's no guide bushing going in there. All I'll need is a hole just larger than the bit the insert ring is designed for - so I guess I'll end up with a few of these things. 

I haven't removed the currently installed 2" aluminum insert ring, which sits on a rebate in the mounting plate itself. It's a thick mounting plate (3/8", 9.4mm) so perhaps the rebate is 3/16" (4.7mm) ? The most simple custom insert ring will simply be a disc of ______ material, slighter thiner than the depth of the rebate - although if that makes it 3/16", it may be a little flexible - depending on what it's made of.

The more complex custom insert ring would be made of thicker material (as long as it's less than 3/8", the thickness of the MP) with the thickness around the edges (the flange) reduced to the depth of the rebate. Quite how I'd do that - in a circle - is perhaps beyond me! Although I did recently make Harry's adjustable circle jig...

Any suggestions re material? I can't see any advantage to being able to see through it (?) - so no need for acrylic. Maybe MDF is fine - or is there something better - given that it needs to be quite stiff, and possible can't be very thick?

Matthew


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## jschaben (Jun 21, 2009)

matt1710 said:


> Hi John / Mike
> 
> Thanks for the suggestions. As always, this forum and its members is a treasure trove of information for a newbie like me. I've read the sticky post re making a new sub-base - I think that's the way to go. I should be a very easy task given that I don't need the high degree of accuracy for the centre hole, as there's no guide bushing going in there. All I'll need is a hole just larger than the bit the insert ring is designed for - so I guess I'll end up with a few of these things.
> 
> ...


Hi Matt - MDF should be fine. I don't think stiffness is much of an issue. The span is very short, <90 mm, and it will be supported all the way around. That, and most of the weight is supported by the table on all but the smallest work pieces.
Will your circle jig cut down that small? I thought it probably would but haven't gone through the old posts to check. I'd make several and leave the pivot hole until they are fitted into plate opening. If to thin, just shim with tape or whatever. If to thick, make a jig from some thin MDF with a nail the size of your pivot hole through it. Double face tape that to your table with the nail sticking up, an appropriate distance from the bit center to allow you to mount the discs and spin them on the table. You can then cut the edges down with a straight bit right on the table.
Just some thoughts


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## Mike (Nov 22, 2004)

Matt, you do not want a zero clearance insert with a router, you need room to help evacuate the dust. You only want to reduce the opening for safety; enough to prevent your material from slipping into the hole. I suggest making one insert that will use the larger Oak Park/Veritas style guide bushings since you can also buy inexpensive bushings to reduce the opening for safety. I know these companies do not ship to kiwiland, PM me about how to order these items.


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## jschaben (Jun 21, 2009)

Matt - Mike has a good point about allowing for dirt evacuation. Whenever possible, I like to get as close to 1/8" larger than the bit size, this leave 1/16" clearance. This can get larger on the larger bits as the workpiece is also usually larger.
I would be a bit cautious about getting locked into the Oak Park/Veritas, or, even the Porter Cable systems though. While they work well for North America and even some of the UK, I would foresee repeated supply issues for you guys down under. I think in a previous thread you indicated a preference of sticking with a metric guide bushing system which I don't believe either the PC or the Oak Park systems support. Instead, I would work on an insert for your plate that will accept the Makita bushings.... I do believe that should be another thread though
Cheers


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## matt1710 (Sep 21, 2010)

Hi MIke / John

Thanks again for your input. I made an insert ring out of 6.5mm MDF, reduced to 4.5mm on the edges where it sits on the rabbet in the mounting plate. It was my first use of Harry's circle jig, and it came out very well. I intend to make a few more rings tomorrow, and will drill them out to sit the most common bits I use. At this stage the ring just has the 5.5mm hole used for the pivot. Good point re dust evacuation.

Good memory John - I do want to avoid imperial if possible - and supply problems too! Thanks for the offer of assistance re shipping here Mike - however I have a solution for that, which I've used a great deal : my sister in law lives in MN.

Matthew


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## harrysin (Jan 15, 2007)

Mike said:


> Since the 3612C is discontinued I almost bought one... $164 was hard to pass up for such a great router. One other thing you might try Matthew, countersinking the screw holes and using flat head screws should give you a bit more clearance.


Let me know Mike if you do buy a 3612C because the two 40mm template guides that I made specifically to give away still haven't been claimed and you can have one with pleasure, I do of course have your street address.


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## Tommyt654 (Apr 5, 2009)

Bench Dog clearance here, AllProTools Bench Dog Liquidation - Liquidation Sale


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## matt1710 (Sep 21, 2010)

Tommyt654 said:


> Bench Dog clearance here, AllProTools Bench Dog Liquidation - Liquidation Sale


Thanks Tommy! Might have a look there to see if I can identify a part I may need.


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## matt1710 (Sep 21, 2010)

Here's a few pics of the router table mounting plate, upside down with the Bench Dog zero clearance bit installed from the underside of the plate. See how far it protrudes below the underside of the MP? My router has to fit flush on the MP's surface, and the ZCI won't protrude through the aperture in the router base. How the heck am I supposed to get that to work?!?


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## matt1710 (Sep 21, 2010)

Here are a few pics of the 6.5mm thick MDF insert rings I created to circumvent the troublesome BenchDog solution. They are 105mm in diameter, with an 8.5mm wide/2mm deep rabbet to allow it to sit on the flange in the MP.

They turned out remarkable well, especially considering it was my first time using my recently built "harry circle jig". Thanks Harry!


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