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Forum topic by Smirak posted 01-08-2018 06:55 PM 519 views 0 times favorited 11 replies Add to Favorites Watch
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Smirak

76 posts in 716 days


01-08-2018 06:55 PM

I need to flush up 4 pcs of 3/4 MDF that has been laminated, making a 3” thick top. First, I used a straight bit and an “edge guide” (straight offcut of MDF) to true up one edge of the top pc, cutting off about 1/8”. Then, I used a 1” depth of cut top bearing router bit to true up the other pcs. However, with my DW618 router, I can’t get the depth to go below two pcs (1.5”). So, I need to get a new/different router bit. WOuld you just go buy the same bit, but with a bottom mounted bearing, or is there a different solution?

Thanks,
Kevin


11 replies so far

View John Smith's profile

John Smith

1481 posts in 360 days


#1 posted 01-08-2018 07:55 PM

Kevin – I also have DW-618 router which is my go-to favorite.

after a few years, you will have quite a collection of router bits.
although they are expensive, try to purchase the ones that have multiple applications.
for edge work like you have now, I would use the 1/2” shank by 3 or 4” cut length with top bearing.
this bit can be used in different situations without buying another bit for similar projects.
I have a truly straight 6 foot builders level that I clamp to the work surface and use the router base
to slide along the level vs the bearing that could leave run marks in the MDF material as only the
cutting edge touches your work project.
once you start cutting, don’t rotate the router: keep it in the same position throughout the cut to avoid
any dips and divots. and you are correct about only taking off 1/8” or so for the final cut. (the less-the better).
the plunge style bit with a top bearing will have many uses. for straight cuts, use a straight edge
that the router base can follow. and for profile cutting, the top bearing will be available.
for thin material and the 3” bit appears to be too long, use a piece of 2” styrofoam as a base and
let the bit cut through the foam. or, glue up some 3/4” sheet foam for your cutting base for pattern making.
as for the top or bottom bearing, both have their pros and cons,
personally, I feel the top bearing pattern bits have more options than the bottom bearing bits.
over the past 40 years, I have probably accumulated a coffee can full of bits. each has their own purpose.
and again, try to purchase the ones that have multiple applications.

.

-- I started out with nothing in life ~ and still have most of it left.

View jerryminer's profile

jerryminer

944 posts in 1639 days


#2 posted 01-08-2018 10:29 PM

I would flip the piece over and use a bottom-bearing bit.

I’ve never seen a top-bearing router bit with a 3” cut length—and don’t think I would want to use one. I have a bit with a 2” CL and it is scary enough for me!

-- Jerry, making sawdust professionally since 1976

View a1Jim's profile

a1Jim

117328 posts in 3775 days


#3 posted 01-08-2018 10:59 PM

You can make one cut with router bit you have then switch to a flush cut bit and run the bearing along the first cut ,it will all look like one cut when you’re through.

-- https://www.artisticwoodstudio.com/videos wood crafting & woodworking classes

View John Smith's profile

John Smith

1481 posts in 360 days


#4 posted 01-08-2018 11:15 PM

yes – the 3” bits are available.
what is really scary is they are also available in 1/4” shank – that would scare the BeJeezes out of me.
(check E-Bay for odd size router bits: search for “extra long router bits”).
I use the 3” bits to hog out mortise holes in 6×6 pressure treated timber for sign posts.
do one side – flip it over – do the other side and if done correctly, the holes will meet equally in the middle
and the sign blade slips into the through mortise and secured with some stainless screws.
I consider myself to be quite proficient with routers and other hand-held cutting tools. so I am very cautious.

.

-- I started out with nothing in life ~ and still have most of it left.

View a1Jim's profile

a1Jim

117328 posts in 3775 days


#5 posted 01-08-2018 11:18 PM

View LesB's profile

LesB

1857 posts in 3641 days


#6 posted 01-09-2018 06:31 PM

MLCS has a 4 piece set for $49 with free shipping. The same set is listed on Amazon for $55.

-- Les B, Oregon

View bonesbr549's profile

bonesbr549

1576 posts in 3265 days


#7 posted 01-09-2018 08:16 PM

why cant you just build up your top in stages.

Get your first layer to the outline you want. Glue up the 2nd layer trim close with a jig saw and then use the first layer and a trim bit and flush it to the 1st layer. rinse and repeat 2 more times and that should get you what you need. Just a thought.

-- Sooner or later Liberals run out of other people's money.

View splintergroup's profile

splintergroup

2422 posts in 1420 days


#8 posted 01-09-2018 08:23 PM

This is what I was going to suggest, you only need a bit with the length of one layer to profile the entire thickness if done in stages.

View Smirak's profile

Smirak

76 posts in 716 days


#9 posted 01-09-2018 08:24 PM

Well…hindsight being what’s it is, I’ve already laminated the layers…I’ll just grab a bottom bearing but with 1-1 1/2” length of cut and flip it over…

Thanks all.

Kevin

View MrRon's profile

MrRon

5190 posts in 3441 days


#10 posted 01-09-2018 10:45 PM

If the top is not too big and heavy, could you run it through a jointer? I know it would be bad on the knives.

View Smirak's profile

Smirak

76 posts in 716 days


#11 posted 01-09-2018 10:46 PM

I could, yes…but no jointer in my garage…

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