Kreg Jig in MDF....

[Corey Hallagan]

I have some sheets of 3/4 MDF laying around and I want to use it for the carcasses of my shop base cabinets. If I use the Kreg to assemble some of the cabs, do I use the coarse or fine screws? Any tips on using the jig to on MDF?

Thanks,
Corey

[Steve Evans]

Corey

Keep in mind that you're getting this advice from someone who's never used the jig on MDF, but if I was a betting man. I would bet that you'd use the coarse screws. You can also try a couple of each out and see if their is any difference.

Steve

[Jim Becker]

Honestly, Corey...not the best method for MDF. There is little or no holding power whether you use the coarse of fine screws, although if you do, the coarse ones are probably better. MDF assembles best with Confirmat screws that are specifically designed for MDF, particle board and other similar products. Because they are pre-drilled with a special step-drill and are larger in diameter, they have good holding power without blowing out and splitting the material.

[Dave Falkenstein]

Corey - Use coarse pocket hole screws in MDF. And I would use glue in addition to the screws. An even better method for MDF cabinets is to use confirmat screws, available from McFeely's, here:

http://www.mcfeelys.com/subcat.asp?subcat=20.1.1.1

Oops - I see Jim and I were answering at the same time - almost the same answer too. Smile.

[Dev Emch]

You want the good news or the bad news? Sorry about this.

MDF cannot not hold a screw for beans. There is one manufactuer of doors in Denver that actually holds a patent on a special inlay strip along the edge of the door to allow for the door hardware to be screwed in. Fancy That!

I would suggest that if your going to use the kreg jig on MDF, that you need to go back after the intial hole is drilled, rebore with a larger hole and glue in a dowel. Come back and redrill the pilot into this dowel and then it will work just fine.

Sounds like a lot of extra work. Its one reason I dont use the kreg jig. Clever idea. But I just prefer not to use it.

[Corey Hallagan]

Hmmmm..... didn't realize this. Well crud, I need the screws in a matter of days. Any chance that these Confirmat screws and drill bits are available at home centers like Home Depot or Menards? Thanks for the info guys.

Corey

[Jim Becker]

Dev, I agree with you regarding pocket screws in MDF or other compressed wood products, but they hold wonderfully in solid stock and plywood, especially when you use glue as you should. (The glue does most of the work) They are fast, strong and self-clamping and also allow for very easy precise alignment...the only thing I use for face frames and similar constructions anymore. But then again, you are also right...preferences count!

[Jim Becker]

Any chance that these Confirmat screws and drill bits are available at home centers like Home Depot or Menards?

Very unlikely. A sheet goods supplier may have them...check your yellow pages.

[Corey Hallagan]

I was planning on using a wood face from on this and use overlay face frame hinges to put on the doors. I will just clamp and glue/finish nail the face frames. Sounds like the Confirmat screws are the answer, problem is time! I have a week off to work on the cabinets.
Corey

[JayStPeter]

I've used both in MDF and prefer coarse. The fine sometimes don't grab.

After reading the other answers, I agree that they won't hold the MDF on their own. I guess I was assuming you were going to glue also. In which case they work great.

Jay

[Jim Becker]

The Confirmat screws are only to assemble the carcass. What you can do to speed things up is use some small square stock to act as glue and screw blocks along the joints on the inside of the MDF carcass...maybe 3/4" square. In this manner you can drill/countersink through the faces of the MDF so your screws/nails will have something to go into rather than the edge of the MDF. It's the edges you have to deal with. I have used this method to build speaker cabinets that you could drop off the back of a truck without problems. Again, you just need to avoid putting "incorrect" fasteners into the edges of the MDF.

Use the pocket screws to build your face frames and biscuits to provide alignment and additional glue surface for fastening the face frames to your MDF carcass.

[Corey Hallagan]

Jay, I would use glue definitely but did the coarse screws pull the two pieces of MDF fairly tight and have you been able to avoid the joints blowing out while putting in the screws?

Corey

[JayStPeter]

Jay, I would use glue definitely but did the coarse screws pull the two pieces of MDF fairly tight and have you been able to avoid the joints blowing out while putting in the screws?

Corey

Yes, and yes. Try on a few scraps to find the right torque setting for your driver. They will strip out if driven too tight. But, the right setting will pull the joint nice and tight. Use the lightest setting that pulls the joint. Using kreg screws I rarely have problems with the pocket hole side. More often, it strips right out and I need to put another hole next to the one that stripped. If you do try to use a regular wood screw there, it will drive itself right on through (same with some plywood).
Also, make sure you have your drill depth collar set properly. If it is too shallow, you leave too much material and it will cause the MDF to split a little. For MDF, I set it on the deep side of recommended so the drill tip is just peeking through.
Heck, since these are only shop cabinets, you can decide if you want to continue using them on MDF based on the results :)

Jay

[Corey Hallagan]

Thanks Jay, it seems like the Confirmant screws that Jim and others advise of are probably the best choice, but I can't get them here quick enough. I will try to use the Kreg screws first and your advise on testing is a good one. Thanks for all your help guys! Also Jay, when you strip a pocket hole out, are you saying you can usually run a regular wood screw in that hole and it will hold or are you saying it doesn't work to do that.
Thanks!
Corey

[Alan Tolchinsky]

Corey, I've found that biscuits hold great with MDF. Do you use biscuits? I'd rather use pocket screws myself ( they're so fast) but sometimes you have to go with what works better. Biscuits!

[Corey Hallagan]

Alan, thanks, I have a Craftsman biscuit joiner that is really a wannabe jointer. It is basically worthless for doing anything but edge gluing up boards. It just isn't as positionable as most REAL joiners are.
Thanks,
Corey

[Dave Falkenstein]

I was planning on using a wood face from on this and use overlay face frame hinges to put on the doors. I will just clamp and glue/finish nail the face frames. Sounds like the Confirmat screws are the answer, problem is time! I have a week off to work on the cabinets.
Corey

Corey - I believe McFeely's has expedited shipping available, of course, at a price. I have never seen confirmat screws in a hardware or big box store. You might be able to get them at a screw and bolt supplier, if you have one in your area. In AZ we have Copper State Nut and Bolt.

I made a set of five shop cabinets recently from 5/8 inch MDF. I used dado joints, glue and clamps - no fasteners at all. Glue works just fine on MDF.

[Greg Tatum]

Have you considered the Miller dowel? It uses a stepped drill bit and their own stepped dowels....They are self-aligning and work great in MDF...I beleive you can find them at a Rockler store if you have one near you.....the dowels aren't cheap but do come in a variety of speices....used them for a jig and it has held up well.
http://www.millerdowel.com/

Hope this helps

Greg

I just saw that they are carried by:
IOWA
Woodcraft Des Moines
Retailer 515-457-7890
Puckett Tools & Fasteners Inc. Cedar Rapids Retailer 319-363-2211
Woodsmith Store Clive Retailer 800-835-5084
Farver True Value Newton Retailer 641-791-9614
The Tool Depot Sioux City Retailer 712-293-0274

[Norman Hitt]

Have you considered the Miller dowel? It uses a stepped drill bit and their own stepped dowels....They are self-aligning and work great in MDF...I beleive you can find them at a Rockler store if you have one near you.....the dowels aren't cheap but do come in a variety of speices....used them for a jig and it has held up well.
http://www.millerdowel.com/

If you have a Lowes in your area, they also carry the Miller Dowel Kits and Dowels, or at least they do in our area.

[Mark Riegsecker]

Dev, I agree with you regarding pocket screws in MDF or other compressed wood products, but they hold wonderfully in solid stock and plywood, especially when you use glue as you should. (The glue does most of the work) They are fast, strong and self-clamping and also allow for very easy precise alignment...the only thing I use for face frames and similar constructions anymore. But then again, you are also right...preferences count!



Are you guys using screws on face frames? I thought we were to use mortise and tenon?:confused: How are you hiding them? A dowel?
Are you using tongue and groove to hold the frame to the case?

[Dev Emch]

Yes Mark, I build face frames with mortise and tenon joints. For me, many of the older joints are both traditional and extremely strong. Why re-invent the wheel.

I am waiting for all of the droolling over Lou's shop to dry up before I post some of my shop tours. I will show you a truely trick way of doing these with two "Secret Weapons" from my vintage machine collection. Hint: They are electron burners that are no longer manufactured! Stay Tuned!

[Norman Hitt]

Are you guys using screws on face frames? I thought we were to use mortise and tenon?:confused: How are you hiding them? A dowel?
Are you using tongue and groove to hold the frame to the case?

Mark, you only use the Kreg Jig system to make the face frame, (not install it), putting the screws on the back side of the face frame, which will be hidden on the inside of the cabinet when you fasten the face frame to the carcass. I normally just glue the face frames to the carcass but sometimes use biscuits or preferably the Miller dowell on occassion, especially if I want a contrasting dowell as an accent. I have rarely used a couple of brads just to hold it in alignment while putting on the clamps if it happens to be one that wants to move around too much.

Tongue & Groove will also work, but is too time consuming to suit me.

[Mark Riegsecker]

Yes Mark, I build face frames with mortise and tenon joints. For me, many of the older joints are both traditional and extremely strong. Why re-invent the wheel.

I am waiting for all of the droolling over Lou's shop to dry up before I post some of my shop tours. I will show you a truely trick way of doing these with two "Secret Weapons" from my vintage machine collection. Hint: They are electron burners that are no longer manufactured! Stay Tuned!

We all will be looking forward to that! Take plenty of pics please:D

[Mark Riegsecker]

[QUOTE=Norman B. Hitt]Mark, you only use the Kreg Jig system to make the face frame, (not install it), putting the screws on the back side of the face frame, which will be hidden on the inside of the cabinet when you fasten the face frame to the carcass. I normally just glue the face frames to the carcass but sometimes use biscuits or preferably the Miller dowell on occassion, especially if I want a contrasting dowell as an accent. I have rarely used a couple of brads just to hold it in alignment while putting on the clamps if it happens to be one that wants to move around too much.




Oh I see, on an angle on the back side, I thought through the side. As for the frame glued to the case, are you saying butting the frame up against the narrow edge of the case (3/4) with glue will hold?


[QUOTE=Norman B. Hitt]Tongue & Groove will also work, but is too time consuming to suit me.


You got that right!

[JayStPeter]

Thanks Jay, it seems like the Confirmant screws that Jim and others advise of are probably the best choice, but I can't get them here quick enough. I will try to use the Kreg screws first and your advise on testing is a good one. Thanks for all your help guys! Also Jay, when you strip a pocket hole out, are you saying you can usually run a regular wood screw in that hole and it will hold or are you saying it doesn't work to do that.
Thanks!
Corey

Corey,

I drill another pocket hole right next to the one that stripped or use a clamp if possible. A regular wood screw will blow out the pocket hole. I was saying not to do that in MDF or plywood.
I agree that conformat screws are the best. If I was counting on the screws for structural strength in a knockdown situation, that's the way to go.
I've put together a few shop cabinets, some shoe racks and some other storage cabinets using MDF with either plain butt joints, drywall screws, biscuits, or pocket holes. Frankly, just a well glued butt joint is strong enough to do the job if the cabinet is designed structurally sound.
Lately, I do my quick/dirty cabinets with biscuits and pocket hole screws. The biscuits provide the alignment and the pocket hole screws do the clamping.

Jay

[Scott Loven]

try a little super glue in the hole if it strips out. It should swell the wood in the hole, and make it much harder. I did it all of the time when I used to build RC airplanes.
Scott

[Scott Loven]

I use pocket hole screws on face frames all of the time, they go on the case side of the frame. You will never see them unless you have your head inside the cabinet. You can also use them to secure the FF to the cabinet.
Scott

[John Hemenway]

I use pocket hole screws on face frames all of the time, they go on the case side of the frame. You will never see them unless you have your head inside the cabinet. You can also use them to secure the FF to the cabinet.
Scott

If you are doing a line of several cabinets you can do the pockets for face frame attachment from the outside of the case. When the cabinets are installed the pockets are hidden between the cases. Apply end panels to the ends of a run and you are good to go. The last step might be overkill for shop cabinets ( I know no one here at SMC would go into overkill mode in their shop ;) ). Of course you could use contrasting plugs for the end cabinet pockets to dress up the MDF a little. :p

[Corey Hallagan]

Thanks for all the responses. In the end, even though they are just shop cabs, I wanted them to assemble well with few problems as I have a lot to cover in 5 days. So, in the end I ordred some confirmat screws and a drill bit to assemble the carcass and they will be here Friday, just in time! I will assemble the face frame and drawers with the kreg jig. Thanks for all who provided assistance and information, I appreciate it. Hopefully buy the end of next week, I will be posting my pics with my new shop layout (very small shop) and my new table saw etc.

Corey

[Mark Riegsecker]

Thanks for all the responses. In the end, even though they are just shop cabs, I wanted them to assemble well with few problems as I have a lot to cover in 5 days. So, in the end I ordred some confirmat screws and a drill bit to assemble the carcass and they will be here Friday, just in time! I will assemble the face frame and drawers with the kreg jig. Thanks for all who provided assistance and information, I appreciate it. Hopefully buy the end of next week, I will be posting my pics with my new shop layout (very small shop) and my new table saw etc.

Corey

Corey I'm sorry for taking your post. I hope no harm was done. But my heart :eek: I had no idea there was so much use of screws. I had seen the Kreg jig and often wondered what a guy would use with one. Now I guess I know. Again I'm sorry I butted in, I wish you luck on your project and look forward to the pics:D

[Corey Hallagan]

Mark, I didn't think a thing of it. We are all about learning an soaking up as much info here as possible. I often read someones post and it leads to me having questions of my own. I will be giving the Kreg a workout this week and will let you know what I think about it. I will be using it to assemble the face frames, drawers and positioning the face frame on the carcass in a few places. Take care and thanks!

Corey

[John Stevens]

I will be giving the Kreg a workout this week and will let you know what I think about it.

Corey, please follow up. I recently bought a Kreg jig and often find it more effort than it's worth to get parts to go together accurately. I can either have speed or accuracy with the Kreg jig, but not both. I'm curious to hear what you find.

[Jim Becker]

I recently bought a Kreg jig and often find it more effort than it's worth to get parts to go together accurately. I can either have speed or accuracy with the Kreg jig, but not both.

John, I'm curious about your difficulties as I have not experienced the same. Using the channel lock clamp provided with my jig, I am able to lock things together in exact alignment after applying glue and proceed to screw the joint fast. Other than being sure that the clamp is adjusted to work properly with the thickness of material in question, no alignment problems. Where are you having problems?

[John Stevens]

Other than being sure that the clamp is adjusted to work properly with the thickness of material in question, no alignment problems. Where are you having problems?

Jim, I find I always have at least one of three problems when using the Kreg jig:

(1) The parts shift at least 2mm, even when using the clamps. This seems to be a common problem: http://www.sawmillcreek.org/showpost.php?p=61741&postcount=1 The fixes for the problem include "anticipating" the creep by using shims to offset it; using biscuits to keep the parts from shifting; or drilling through the blind holes: http://www.sawmillcreek.org/showthread.php?t=8119&highlight=kreg

(2) The non-perpendicular pull of the screws draws parts away from a 90-degree angle in situations where parts are intended to be joined at 90 degrees.

(3) Pocket-hole joinery takes too much time if you need to also use biscuits or drill out the blind holes. When I say "too much," I'm thinking relative to other joining methods, such as splines, floating M&T or biscuits, all of which may take marginally more time, but result in better alignment and adequate strength.

The more I tests I perform with the Kreg jig, the less I see it as a time saver compared to other methods of joining pieces. At this point I wouldn't use the Kreg jig on projects other than shop aids, but even there I've been choosing to use biscuits and glue instead.

[Jim Becker]

Interesting. I've never had a problem with shift or misalignment and as far as speed goes...it's been lightning fast for me. The only time I use buscuits is to actually attach a face frame to a cabinet and then only for alignment while I'm clamping up. Maybe I've been lucky. I don't know. But the bottom line is...if it isn't working for you and you can't solve the issues, use a different method. There are so many to choose from!

[mike malone]

I hate at this point to admit it but I have often used the gold # 6 and # 8 coarse screws on 3/4 MDF from HD (2" scr.) Predrill and countersink, of course. Never over torque them. I used these on many box frame cabinets and have NEVER had a problem. doors were hung with Blum and Grass euro hinges...and honestly NEVER a problem. IF the box was subject to a lot of racking or movement, (don't know how as the cabinet just sits there against the wall.), i'd add bisquits.
good luck :)

[JayStPeter]

John,

I've had shifting problems also. I am not a fan of the Kreg face frame clamp. In fact, I just found it in the bottom of a 5 gal bucket full of small clamps and c-clamps. I hadn't seen it since moving and building my new shop and haven't missed it. I haven't found it satisfactory for holding parts in place, it is extremely wimpy and allows the joint to shift. Maybe they cheapened them, as others like Jim have found them useable. I agree that you need your parts well clamped to run the screws without shifting. But, IMO, it is a timesaver.
For faceframes, I usually set up a clamping jig to clamp each corner into place. Then I zip come PH screws in to hold it tight, unclamp, and move on to the next corner. It's pretty quick and I can do a number of faceframes (sometimes makes up for my lack of clamps).

In a pure clamped cabinet glueup, my method is to test the entire glueup with clamps to ensure everything fits OK. Then, full disassembly and reassembly with glue. Sometimes, it takes multiple practice runs to get a good order going.
With pocketholes, I assemble the whole thing dry. Then I can pull some of the screws out, put on glue and zip it back together piece by piece. Way faster than dorking around with clamps and full disassembly. Plus, no stress if the phone rings or wife calls.
Sometimes you have to put together a couple sub-assemblies, then go to the full assembly. Instead of waiting for glue to dry on a normal biscuit, spline, floating m&t etc, if you pocket hole the subassemblies together you can go straight to full assembly without waiting for glue to setup. Plus, you can test fit those subassemblies in the full piece without glue first.

Plus, I like them for attaching tops. I (via Norm) use a regular drill bit to slot the hole when accounting for wood movement is necessary.
I also like them a lot for places where slight shifting won't matter, such as unseen support blocks.

While I like pocketholes (and you'll usually find some on my projects), I just view them as another form of joint (or clamp) and don't force myself to use them because they are easy and fast. But on shop cabinets ... easy and fast is good.

Jay

[John Stevens]

Jay, thank you very much for your detailed post. I'm just a beginner, so I've only built frameless cabinets. I like the look and it seems easier to me, so I doubt I'll ever want to mess around with face frames, but who knows?

For shop cabinets, visible screw holes don't matter to me, so I've only used the method from the late Danny Proulx's books: 2" coarse-threaded screws to join MDF or melamine-coated chipboard with simple butt joints--no rabbets, grooves or dados. Just clamp 'em with 90 degree assembly braces (http://www.leevalley.com/wood/page.aspx?c=2&p=51101&cat=1,43838), drill and drive. The test-runs I've done with pocket holes have been more time-consuming and less accurate. Proulx's method allows the screw holes and seams to be hidden when necessary for kitchen cabinets and built-ins, and strength is surprisingly robust.

I was really hoping to be able to use the Kreg jig to assist with gluing up large panels and carcases made of solid wood, but due to the intermittent problems I've had with shifting, I wouldn't risk it. Nevertheless, you've given me a lot to think about, so I'll have to digest that before I decide whether to return the Kreg jig. Thanks again.