Bora Centipede Table Top As Alternative to Bench Dog Hole Pattern Guides

[Barry Blitz]

Looking to get into a MFT DIY solution using 3/4" on 4" spacing. All the guides out there are quite expensive or have limited amount of guide holes. Plus, they seem to never be in stock. Making my own jig could never be as precise, and I don't want the expense of paying for local CNC work. So, what about using a $70 Bora table top (they come in both 3/4" and 20mm hole patterns) for a pattern guide for use with a quality 1/2" plunge top bearing flush trim bit?

451798

[Paul F Franklin]

I picked up one of these a couple weeks ago. I don't see why it wouldn't work as a pattern. I didn't make precise measurements of its accuracy, but I did lay a straight edge against various combination of dogs in the holes and they lined up nicely, even across the hinge. Checked for square from row to columns as well and that was good too. You might play it safe and just use 1/2 of it so there is zero chance of any play in the hinge being an issue, but on mine the hinge has no noticeable slop. Probably a different story after a period of use, since the hinge is just heavy plastic.

Some folks on the tube buy the little top festool makes for a systainer and use that as their pattern; this one would take fewer step and repeat moves to do a large surface.

[Jim Becker]

I might trust one side of that for the pattern, but wouldn't span the hinges for that purpose because there may be some variability introduced by said hinges. You'll want tos very precisely sized dogs long enough to allow you to overlap the pattern to move it over to extend the pattern.

[glenn bradley]

I have one and it seems to work great. I would pre-drill the holes using a dowel as a centering spacer. This will save a lot of wear and tear on your router bit. I used a 3/8" template bit.

451820 . 451819

This is for a different layout but, the same method applies.

[Barry Blitz]

I picked up one of these a couple weeks ago. I don't see why it wouldn't work as a pattern. I didn't make precise measurements of its accuracy, but I did lay a straight edge against various combination of dogs in the holes and they lined up nicely, even across the hinge. Checked for square from row to columns as well and that was good too. You might play it safe and just use 1/2 of it so there is zero chance of any play in the hinge being an issue, but on mine the hinge has no noticeable slop. Probably a different story after a period of use, since the hinge is just heavy plastic.

Some folks on the tube buy the little top festool makes for a systainer and use that as their pattern; this one would take fewer step and repeat moves to do a large surface.

Good to know the accuracy looks there.
Agreed, I would only use one side and remove any attached hardware that prevent flat contact.

[Barry Blitz]

I might trust one side of that for the pattern, but wouldn't span the hinges for that purpose because there may be some variability introduced by said hinges. You'll want tos very precisely sized dogs long enough to allow you to overlap the pattern to move it over to extend the pattern.

I will definitely need bench dogs with excellent tolerance to index. And I would use the outside holes to index against the outside corner of the workpiece to ensure square.

[Barry Blitz]

I have one and it seems to work great. I would pre-drill the holes using a dowel as a centering spacer. This will save a lot of wear and tear on your router bit. I used a 3/8" template bit.

451820 . 451819

This is for a different layout but, the same method applies.

I am not sure how to bore the holes. You are right about wear, especially on the plunge. Alternatively, I could bore with a 1/2” spiral and then follow with the plunge trim bit, which would have minimal plunge engagement. Or follow with the 3/8” flush if I had one.

sorry, I can’t see the images, probably due to my low post count.

[David Miller]

I did something similar. I purchased a Festool replacement top:

https://www.amazon.com/gp/product/B003KN3V3W/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1

I used a plunge router with a flush trim bit. I'd go deep enough with the Festool top to establish the hole. Then I'd go over the holes again making them deeper without the Festool top. It worked although you have to be careful with each hole as you plunge. I messed up one hole in the top.

[Barry Blitz]

I did something similar. I purchased a Festool replacement top:

https://www.amazon.com/gp/product/B003KN3V3W/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1

I used a plunge router with a flush trim bit. I'd go deep enough with the Festool top to establish the hole. Then I'd go over the holes again making them deeper without the Festool top. It worked although you have to be careful with each hole as you plunge. I messed up one hole in the top.

Yeah, that is my concern. If I start the plunge with a 1/2" spiral and then finish with the flush bit, then my only risk is the bottom of the template. I can live with a couple of mm on the bottom of the 3/4" template hole being chewed. The problem I also foresee with a top bearing is that if I tilt the router due to poor technique, then the bottom of the routed hole might get a little elliptical (better the bottom of the dog hole than the surface). I don't want to do any bottom bearing work since I feel more comfortable with the template on top.

[David Miller]

Another 'bother' is having to keep the hole clean so the trim-bit bearing has a clean surface to ride on.

You are correct about needing to keep the router plumb. Will you be using a plunge router? That's what I used.

I like Glenn's idea of pre-drilling the holes. I may try that next time. Unless I get a Parf-guide....

[Barry Blitz]

Another 'bother' is having to keep the hole clean so the trim-bit bearing has a clean surface to ride on.

You are correct about needing to keep the router plumb. Will you be using a plunge router? That's what I used.

I like Glenn's idea of pre-drilling the holes. I may try that next time. Unless I get a Parf-guide....

Definitely a plunge router for the spiral and trim bits. And you are right, gotta keep that template hole clean! I will add blasting air and checking with a quality dog for each bored hole before I move the template.
I figure the purchase of the Bora table will yield two large templates, and if one side of the template gets chewed, then it can be flipped for one more use. So, really a total of 4 single use templates in the worst case scenario.

[Dave Sabo]

I’m gonna be that guy.

Making holes , especial multiples , like that has got to be the most in inefficient, least precise and time consuming way to it. Woodpeckers’ jig is set up that way and it’s daft.

3/4” holes are fairly common, though 20mm seems more popular in my orbit. Your real issue is going to the 4” spacing. I know of no commercially available tool / template with that layout.

If you’re not going to be making a lot of these , a cnc shop will be you’re best and most economical bet , despite your thinking they charge a lot. If you are , I still think a cnc shop to make a template with the spacing you desire is also the way to go. I’d design it like the taiga tools jig so you can use plunge router with a template guide bushing and use either 20mm or 3/4” holes simply by changing the bit.

Frugal is one thing - and then there’s a skinflint.

[Barry Blitz]

I’m gonna be that guy.

Making holes , especial multiples , like that has got to be the most in inefficient, least precise and time consuming way to it. Woodpeckers’ jig is set up that way and it’s daft.

3/4” holes are fairly common, though 20mm seems more popular in my orbit. Your real issue is going to the 4” spacing. I know of no commercially available tool / template with that layout.

If you’re not going to be making a lot of these , a cnc shop will be you’re best and most economical bet , despite your thinking they charge a lot. If you are , I still think a cnc shop to make a template with the spacing you desire is also the way to go. I’d design it like the taiga tools jig so you can use plunge router with a template guide bushing and use either 20mm or 3/4” holes simply by changing the bit.

Frugal is one thing - and then there’s a skinflint.

Thanks for your input Dave.

As a hobbyist, I am choosing 3/4" for frugality. No Festool accessories are in my plans. Can you please explain why 3/4" dogs with 4" spacing is something I should not pursue?

With respect to accuracy, I am sure the Bora is CNC, like you suggest. Even if it turns out to not be 4" spacing, as long as it is the same spacing I do not see why that should matter.

Regarding inefficient time use, I would think the highly regarded Parf system epitomizes that. The Parf system requires two hole bores per hole as well, but you then have to reposition the jig each time. The Bora template has 36 holes per positioning. Further, the Bora system can be referenced outside the table top to match the square of the top, but the Parf requires that the Parf ruler is used to layout the first line of holes. If this ruler placement is a little off then the entire grid pattern will be out of square with the table top (that error increase with the size of the table).

[Jim Becker]

Barry, there's nothing wrong with doing .75" holes on a 4" grid if that's what you prefer. Function is what matters most.

But it's good to consider that the market for dogs and accessories is a pretty broad these days for 20mm holes on a 96mm grid. Some clamping type accessories can accommodate both because of a cam-action stem. While Festool certainly helped bring that about with the MFT over a couple of generations, you don't have to have a single Festool tool to utilize it.

[Barry Blitz]

Barry, there's nothing wrong with doing .75" holes on a 4" grid if that's what you prefer. Function is what matters most.

But it's good to consider that the market for dogs and accessories is a pretty broad these days for 20mm holes on a 96mm grid. Some clamping type accessories can accommodate both because of a cam-action stem. While Festool certainly helped bring that about with the MFT over a couple of generations, you don't have to have a single Festool tool to utilize it.

I still have not made up my mind on 3/4" versus 20mm. You are right about the 20mm ecosystem. There are more ingenious options burgeoning in the 20mm market and they are tempting. And pricey. I am more of a DIY jig guy and if I went 3/4", then it actually helps me from splurging on those shiny, beautiful accessories.

The thing about options, is the more you have, the greater the stress in making the decision. Back in the day, it was either a black Ford Model T, or not. Coke or Pepsi. With more options, becomes more buyers remorse, second guessing, retrospection. Decisions, decisions, decisions....

[Jim Becker]

Barry, I actually have both 20mm and .75" on my main bench...the latter in three rows so I can use my "beloved" Gramercy holdfasts which will not work in 20mm holes and the rest all 20mm. Now this is a general purpose, heavy bench that I designed for my own purposes. All my other work surfaces use the 20mm grid. The bottom line is that it's nice to have choices!