Worktop jig instructions if walls out of square - incorrect?

Discussion in 'Kitchen Fitters' Talk' started by ajohn, Mar 24, 2019.

  1. ajohn

    ajohn Active Member

    Walls are out of square so could trim the back of the worktop to suite so that I could do square joints but wonder about angling the joint instead. Bit of trimming of the back of the worktop instead of cutting along the entire length.

    The instructions with the jig say this

    JigTilt.jpg

    As the female is cut first I'd have thought that it was best to always angle the jig by 1/2 the error if it matters. In my case there is 6mm error so offset by 3. Then scribe the male joint and set the jig to do that.

    So in my case on the female part trim the end to match the wall it runs to. Trim the far right back end a bit to account for plaster bulging out. Set the jig up with just one front guide peg and out of square by 3mm. Then scribe the male run of worktop off that, set the jig up to it and etc.

    ;) Makes sense ? I can only scrap one joint. Alternative is to trim maybe 20mm of the entire length of the worktop and also shape the end to fit the wall.

    John
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  2. CGN

    CGN Well-Known Member

    Cut the worktop to fit the wall, with the correct over hang at the front. If it’s really out of square, then yes, halve the errors by offsetting the female joint and cut this. Get the adjoining worktop in place and overlapping and scribe for male.

    If in doubt, get some 18mm mdf cut to worktop width to practice/template. £20 is a lot cheaper than a new worktop.

    There are a couple of guys on here ‘kitfit’ and ‘metro’ who fit kitchens day in day out, so I’m sure they’ll have something to say.
     
  3. ajohn

    ajohn Active Member

    LOL Hope they say it soon.

    If I set the front edge of the worktop to suite the units I could finish up needing to trim off 20mm to nothing off the entire length at the rear. For overhang at the front that's a bit nail biting. Effectively none in respect to the front of drawers etc. Ikea seem to expect it be installed a little like that so that runs up to tall cabinets look ok. I've packed that out off the wall to give a bit more flexibility.

    Alternative is arrange the worktop so that visually it looks ok from the front with some overhang. That results in 6mm error along the length of the joint as the walls are angled at over 90 degrees, about 96 degrees.

    I have some thin mdf, shelves off racking that we don't use any more. I used some of it to make templates for a run in an alcove that holds the sink so could use it easily to test one half of a joint. Both halves, tricky. I do have excess length so other than the joint angle there is scope for adjustment on both pieces.

    John
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  4. CGN

    CGN Well-Known Member

    You can always chisel a bit out of the plaster if the skim is deep enough.
     
  5. ajohn

    ajohn Active Member

    Not worth it for the sake of trimming a few mm of the back of worktop at an angle for about 150mm to get the corner to fit.

    John
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  6. CGN

    CGN Well-Known Member

    Was just a suggestion as it’s easier to rectify a wall than a wrongly cut worktop.
     
  7. ajohn

    ajohn Active Member

    I'm very confident that I wont mess that aspect up. Already done similar that was a lot more difficult than this piece will be. I did cut back the corner of one wall as it was well over 15mm out - before the plasterer came in

    Only worry really is that the jointing method is sound and will cope with the error, mainly the angle coming out correctly. The fit of the curved section can be adjusted within limits. The out of square problem doesn't seem to be covered in tutorials so asked about on here some time ago - one fitter mentioned adjusting the jig angle if they noticed the error ;) Pretty obvious in my case, he would notice. The instructions put a measurement on how much to misalign the jig. Sounds ok but ........ so asking.

    John
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  8. ajohn

    ajohn Active Member

    Bit more info. This is a note they add about when the jig is set at an angle

    JigTiltNote.jpg

    To make that clearer

    JigTiltImage.jpg

    The video tutorial I mentioned cuts the male like that in case the walls are out of square, just the F1 peg and align to the scribing. He has to pull the male board forwards a bit to get it to match so maybe using that peg insures that.

    ;) One thing for sure is that I will cut the male on a scrap bit or MDF before wasting a piece. To be honest I would be tempted to make the female a little too long and trim it's end to match the male rather than have to pull the male board back. :) My time is free.

    John
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    Last edited: Mar 24, 2019
  9. ajohn

    ajohn Active Member

    The final bit - angling the jig for the male


    JigTiltMale.jpg

    ;) Having problems getting my head around angling both doubles the angle as suggested - suspect it does as one side is always done upside down - but.

    They mark the reference line shown on that by measuring from the end of the board accounting for the usual 9mm jig offset so suppose it checks that the pins have set it correctly for a square joint. If it's aligned 9mm off a scribed line of an angled female my brain wont get around that doubling the angle.

    :( On my version of the jig they haven't labled the M holes

    John
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    Last edited: Mar 24, 2019
  10. dubsie

    dubsie Member

    Jesus time to call a joiner. I wouldn't know where to start.
     
  11. kitfit1

    kitfit1 Well-Known Member

    Been away since Friday so only just read this thread and have to leave for work in a few mins. OP, i'll post up a straightforward, easy and fast solution tonight when i get home. Far too many of these "guides" are over complicated when the solution is actually quite easy.
     
    ajohn likes this.
  12. ajohn

    ajohn Active Member

    Easier if you ignore what they say about the male joint. The usual way of handling that is to place the worktops in position after the female joint has been cut and scribe the female profile onto the male usually with a pencil. Then align the jig with another line 9mm off that. To do that on the male only the M1 peg can be in.

    The male joint will only be too long if the female was cut for square and the walls are out. Halving the error in the walls when it's cut gets round that. Both joint lengths should be the same.

    :) Then you've jointed it, fit in place and find there's an error and a gap between the wall and worktop that tiles or the trim wont hide. Simple, scribe off the wall onto the worktop and trim down to fit by enough to reduce the gap. Some gap is ok so probably no need to do the whole length eg 1/2 the length would 1/2 the gap.

    LOL Best thing when confused is to forget, go to bed and sleep. Probably much clearer in the morning.

    The only worry now is how this man cuts the females. Seems sensible to me especially as the jig i have doesn't have a peg for the width of worktop Ikea supply. It's easier to put the male length on top of the female when scribing rather than transfer sides as he does. He sets up for females by marking the width of the worktop on the side to be cut and sets the jig off that. Works for any width even if a standard width has been trimmed for some reason.



    John
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  13. ajohn

    ajohn Active Member

    Thanks. May as well mention me plan of attack.

    It's a U, one side very short. So top of the U flat on the wall. I removed plaster there and boarded it up. Bit of a surprise when I removed the old sink. Left hand side adjusted to look nice to the units rather than exact overhangs. Female in that. The other side of the U only sticks out by under a 1m so rather than have a short bit that would be hard to support female in that side as well. ;) There's a built in dog cage going under that and the width will be reduced to about 550mm so scope for trimming to suite that wall whatever angle it's at.

    As all of the wall error is taken up by the left hand side there is a fair gap between the end and the wall so first thing trim that to match the wall also a bit of work on the back in the corner to give a bit more scope for moving the parts around. Then arrange the bits and get on with it. The work on the back is just releaving the corner a bit.

    John
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  14. ginger tuffs

    ginger tuffs Active Member

    if you cut one side of worktop then put other worktop on carcase then pack up and put cut worktop on then scribe joint making sure front corner is right in other words placing worktop on top of each other
     
  15. kitfit1

    kitfit1 Well-Known Member

    Ok, going to reply to your first post because the others have just cunfused the hell out of me and make no sense.
    Let's start by me assuming ALL of your base units are in line in each run and perfectly flat and level ?
    If that is the case, working in a clockwise direction you lay a length of top on the first run into the corner about 50mm over length, run a spirit level on it's side against the right hand wall and mark the worktop, then cut the top along that line. Put the worktop back, then do the same with the next length of worktop using an offcut at the other end to hold it up. Once you put that length back on top, use a set square to mark the front edge of worktop 2 onto the front edge of worktop 1. Remove worktop 1 then using a 45 degree set square, draw a line on the top of the worktop lining up with the front line, measure 9mm away from that line and mark another line. Put your jig in place with both F1 and F2 in place and line the back of the slot at that 9mm line, then clamp the jig and route away. Put the top back in position. put worktop 2 on top of it in position, then from underneath draw a line along the joint of worktop 1 onto the bottom of worktop 2. Remove worktop 2 and then mark another line 9mm away from the line you have drawn. Set the back of the slot at that 9mm line with just M1 in place, then route the top. Put both tops in place and then rinse and repeat for the next top. Dead easy and works every time.
     
  16. dubsie

    dubsie Member

    I think joiners have the hardest trade, you gotta know bloody everything from roofs to timber frame houses to kitchens. If they get stuff wrong every trade that follows them has a hard time.

    No wonder so many become site managers.
     
  17. ajohn

    ajohn Active Member

    Thanks. As the jigs clearly use 45 degrees I had wondered if that fact can be used as it gives a precise setting.

    I've been making a number of measurement and moving things around. Looks like my best option is to go for a more or less square joint. It means a bit of fiddling about but worth it in the long run.

    It's using Ikea's extra worktop width to part correct the angle error by cutting a tapered section of the back. It'll run from about 12mm to zero. There will be a gap to the wall for some of the length but under the thickness of the tiles so just need to stick something in that to stop silicone rubber running through when the tiling is done.

    :) You'll have to forgive me for the other thing I will do at the back. I can gain 8mm less gap by shaping the corner to fit the wall. Bulges out as usual. ;) I'll route round a template in 6mm mdf for that. Took me a couple of mins to mark it out and wont take much longer to shape it.

    Works out well as it finishes up with the same overhang as the top of the U untouched and as fitted. The overhang on Ikea units can't be that big if a section runs up to a tall floor cabinet. I've spaced mine out so can have some. Otherwise they'd have to be more or less flush to the drawer etc fronts - that's how their displays are done. I didn't notice when we looked and ordered. I suspect they do it this way so people can trim to suite the wall. I'd rather have a small overhang, say 12mm past the fronts.

    John
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  18. kitfit1

    kitfit1 Well-Known Member

    You are doing so much "overthinking" it beggers belief. Just do what i said, and it will work :D
     
  19. ajohn

    ajohn Active Member

    LOL Yes I know. Plenty of time, I need my "labourer" and not available at the moment. The tops are a bit too heavy for me. Glad I couldn't get straight into the angled jig idea. Spare time so measure up for 3 options. Plus of course when it gets to the joints exactly what you have suggested.

    Be fair though. Cabinets are where they need to be due to the walls and I'm pretty sure if you fitted them you wouldn't just run them along the walls but would blame me for how the cabinets are installed. All of the error is on wall. I'm pretty sure anyone that looked would notice the change in the overhang. ;) Worse for a DIY's as I'd know that it was a stupid amount out.

    ;) Other problem of course is I'm an engineer, ;) fully indentured toolmaker, old style so inclined to work to 0.001" or better,
     
  20. ajohn

    ajohn Active Member

    :eek: What went wrong ?

    ;) One mistake was mine. Aligned the jig on the wrong 45 degree line for the female so joint is 9mm too short.

    Thin piece of mdf for practice so had to mark the top of the male and transfer to the back. The long cut edge is under 1/2mm out from the line transferred to the rear so like marking 8.5mm+ rather than 9.

    The pieces can be arranged like either of these.
    JigProblemA.jpg

    The gap is about 1mm.

    JigProblemB.jpg

    Not happy about either. The joint angle is about 5 to 6 degrees out of square. Is this down to that or being 1/2mm out on alignment.

    The scribed pencil line is out because I scribed against the reduced length female to get the correct joint angle.

    John
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