# 3/4 inch spiral up cut bit



## SRVDVM (Nov 13, 2012)

I need to make a LARGE number of 3/4 inch holes in 1/2 plywood for a work bench project. The directions say to use a 3/4 inch spiral up cut bit. All I can find are 3/4 inch with 3/4 shanks. So, I'm a littl confused as I'm new to routers. I thought routers only came with 1/4 and 1/2 inch colletts. So how do you use a 3/4 shank bit??
Do they make 3/4 inch spiral upcut bits with 1/2 shanks??

I have a Triton TRC001 3-1/4-Horsepower and a DEWALT DW618B3 12 Amp 2-1/4 Horsepower Plunge Base and Fixed Base 


The project I'm working on a designed by Ron Paulk >> you can search for "Paulk Workbench" if you are interested. It really is a cool bench, especially if you need soemthing that can be packed up and taken to the job site. It does have a built in router table. 

Thanks for helping a novice router person


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## SRVDVM (Nov 13, 2012)

I found one - not easy to google this bit

HSS Up-Cut Spiral End Mill Bit 3/4"

Hope this helps others that may be looking for something similar


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## kp91 (Sep 10, 2004)

SRVDVM said:


> I need to make a LARGE number of 3/4 inch holes in 1/2 plywood for a work bench project. The directions say to use a 3/4 inch spiral up cut bit. All I can find are 3/4 inch with 3/4 shanks. So, I'm a littl confused as I'm new to routers. I thought routers only came with 1/4 and 1/2 inch colletts. So how do you use a 3/4 shank bit??
> Do they make 3/4 inch spiral upcut bits with 1/2 shanks??
> 
> I have a Triton TRC001 3-1/4-Horsepower and a DEWALT DW618B3 12 Amp 2-1/4 Horsepower Plunge Base and Fixed Base
> ...



You can do it with a 1/2 inch router bit and a template. It would probably be A LOT cheaper, as well. a 3/4 inch solid carbide bit will set you back over $100.

You can use a straight plunging bit, and just make the cut plunging up and down to clear the chips.

magnate.net might be a place to look for good priced, quality bits.


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## del schisler (Feb 2, 2006)

they have this it has a 1/2" shaft and 3/4" cut this bit is made by onsrud company This is lee valley 
Lee Valley Tools - Important Announcement


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## Semipro (Mar 22, 2013)

Try here 
Lee Valley has them
Made for making bench dog holes

86J01.42
3/4"
1-1/4"
1/2"
$44.90
$40.40


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## Mike (Nov 22, 2004)

MLCS has this:


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## cagenuts (May 8, 2010)

If this is a once off requirement, then why not buy an old brace drill for about $10 and a 3/4" auger bit for $1 and drill away.

Not worth even selling them again.


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## geoff_s (Apr 14, 2012)

I built my Ron Paulk workbench without the holes due to the difficulty/expense of finding a suitable bit.
With the above supplied information, I might rethink the whole hole thing!


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## SRVDVM (Nov 13, 2012)

Thanks Mike,
Considering this is most like a 1 job bit, $14.95 with free shipping (not sure how long it will take but I'm not in a big hurry) isa good deal. I'm going through 2 sheets of 1/2 ply and the cutting depth is 1.25" so this will be perfect.

Thanks again


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## MT Stringer (Aug 15, 2012)

I used a Forster bit in a drill motor.


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## SRVDVM (Nov 13, 2012)

MT Stringer said:


> I used a Forster bit in a drill motor.


That would work, but then I'd have to buy a 3/4 inch Forstner bit......


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## MT Stringer (Aug 15, 2012)

Quit being a cheapskate and git-r-done!


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## SRVDVM (Nov 13, 2012)

Well, I ordered the MLCS bit last Tuesday. Got it Friday, with free shipping. The project calls for 110 holes going through two 1/2 inch sheets of plywood - 1 inch total. Well, 1/2 way through and I've burned the bit up. So, either it's a cheap bit, I screwed up or a combination of both. I used my Dewalt listed above. Question is, what speed to run this bit at for the purpose of plunge cutting these holes and how hard do you press?? I started at "2", then tried "6" (way to fast) and settled on 4. This is a 2 1/2 hp router, max speed 24,000 rpm. Any tips would be appreciated. This it's the first time I've done something like this - still new to using a router. Guess I'm going to learn a few things with this project


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## Alan Bienlein (Oct 17, 2009)

About 55 holes with a 3/4" HSS spiral bit thru 1" of plywood is asking a lot. If you want it to last you need carbide or you need to slow the cutter down.


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## Mike (Nov 22, 2004)

Scott, this is why in my thread about choosing bits I do not recommend HSS bits for people starting out. The bits lose their edge 5 times faster than carbide. All is not lost, these bits are easy to touch up with a diamond sharpener. I use Trend Tool and Bit Cleaner to remove any resins from the bits and their credit card diamond sharpener and cutting fluid to sharpen bits and blades. HSS bits require regular maintenance but they can perform better in some situations than carbide bits. If you are looking at getting this done for the least trouble possible then the easy way is to order another bit.


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## cagenuts (May 8, 2010)

Mike said:


> Scott, this is why in my thread about choosing bits I do not recommend HSS bits for people starting out. The bits lose their edge 5 times faster than carbide.


Playing devil's advocate here, given the price is significantly cheaper than carbide tipped router bits, perhaps for the once off job the HSS bits are fine?


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## Semipro (Mar 22, 2013)

Scott 
How did the bit work when it was new how many many holes did you get before it went bad ( that is a lot of holes in plywood) I only ask out of coriosity
I also agree with Mike I sharpen my bits all the time with a diamond file


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## SRVDVM (Nov 13, 2012)

I was Abe to get 62 1/2 holes done - would not go into the second sheet on the 63rd hole. It did great for the first 22 holes. I started to get some burning shortly after that. That's when I started playing with the bit speed. I realized I'd hit a point of no return and was hoping to finish out all 110 holes - well, that didn't happen. I'm going to get w new carbide bit and keep the old one fir when I get some things for sharpening bits. Any suggestions on bit sharpening kits/equipment. Seems they've become a priority on my wish list....


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## SRVDVM (Nov 13, 2012)

Ok, I see where Mike recommended Trend Tool


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## SRVDVM (Nov 13, 2012)

Hmmmm just read on the Rockler site that sharp bits, if dirty, will cut as if they are dull - I'll try cleaning the bit first. Wondering if all the glue in the plywood has just gummed everything up - worth a ****


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## SRVDVM (Nov 13, 2012)

Oops, that was supposed to be worth a shot....sorry


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## jw2170 (Jan 24, 2008)

Are you using a non-plunge cutter to plunge into the plywood. The bottom cutting edges are not designed for plunging and will wear out very quickly.

Although not cheap, I would use a solid carbide spiral plunge cutter.


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## Mike (Nov 22, 2004)

James, the holes are 3/4" so that pretty much rules out solid carbide.


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## jw2170 (Jan 24, 2008)

Ah well, I thought you could get anything in US.

I still believe the OP needs a plunge cutter, not an ordinary 3/4" cutter.


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## SRVDVM (Nov 13, 2012)

I did not know there were two types - plunge vs non- plunge cutter. The bottom of this bit is not quite but almost flat. I'll have to look into that. As Mike said, I could not find a carbide bit in this size.


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## cagenuts (May 8, 2010)

SRVDVM said:


> I did not know there were two types - plunge vs non- plunge cutter. The bottom of this bit is not quite but almost flat.


If you are using the bit for creating a dado or groove then the flat bottomed bits are fine as the debris is ejected behind the spinning bit.

When plunging however, there's nowhere for the debris to go so you need a small notch in the middle to accommodate this requirement.

If that's all you have, then perhaps use a normal brad bit of a smaller diameter to drill the pilot holes and then make up a jig (off-set base) with a dowel the same size as the brad drilled hole to position the router for the 3/4 bit.


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## SRVDVM (Nov 13, 2012)

I'm using the bit Mike has highlighted in the 6th post of this thread so I'm guessing I have the correct bit. I contacted Ron, the designer of the bench, and he used a HSS bit from Onsrud. In the video he did not seem to have any trouble and finished all the holes in about 15 minutes


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## Mike (Nov 22, 2004)

Scott, I did not realize how many holes you needed to rout or I would of suggested buying two of the HSS bits. This is still a cost savings over a carbide bit and more than likely the only time you would use them.

It is not difficult to sharpen your bit, consider getting the Trend credit card sized diamond sharpener and their lubricant. You will be able to use these items to sharpen your other router bits and saw blades; one side does HSS and the other does carbide. It only takes a few light passes to restore a bit, well worth the investment. I am very pleased with mine. BrianS has tried them out; lets see if he jumps in with an opinion.


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## Botelho007 (Sep 23, 2012)

In my workbench to 20mm used this:

Amazon.com: Freud CB20057R Industrial Carbide Tipped Cylinder (Hinge) Boring Bits Right Hand 20mm Diameter -10mm Shank - 57.5mm Length: Home Improvement


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## SRVDVM (Nov 13, 2012)

Just an update. Got a new bit and some small diamond sharpeners. I was able to drill the rest of the holes but I had to periodically stop and sharpen the bit. I needed to learn to do that some time..... In Mike's thread For Advanced Users Only, he mentioned that HSS bits should not be used with plywood, but we know this bit does not come in carbide so we're stuck. However, Festool has an 8mm shank 20mm hinge boring bit in carbide that is close enough to 3/4 inch. F-clamps can still be used and the Festool clamps used on Festool tables are just shy of 20mm, they are 19.83 mm so they should fit but may have a little play. My bit cleaner solution is in the mail so I'm going to try to clean the durst bit up and sharpen it - see if I can save it. Mike's thread on Rusty Bits was encouraging.
I do have a ? About sharpening a spiral up cut bit. I can easily sharpen the bottom part but how do you do the sides/spiral part of the bit? 
Thanks for gage help, especially Mike


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## SRVDVM (Nov 13, 2012)

Oh, I'm not sure how to use/adapt an8mm shank fir use in 1/4 or 1/2 inch collet. I think there are adapters that can be used


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## jw2170 (Jan 24, 2008)

Hi Scott.

I believe that spiral cutters will have to be sharpened professionally.

There are many 8mm sleeves for 1/2" collets, but you may have to look in UK or Australia.


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## Mike (Nov 22, 2004)

Quality 6, 8 and 12 mm collet sleeves are available in the US from several sources.


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