Metric Threaded Table Inserts

How To Workholding
1

Hi All,
Can somone let me know what the recommended hole size is for these inserts so that they can be screwed in far enough to be well below the surface of the MDF table top? I am wondering if I need to do two different pockets, one for the threaded part and one for the flange on top of the insert.

Thanks,
Mark

2

I found it was better to add the inserts from below the MDF spoilboard, way harder for them to pull out that way and they’re recessed as far as they’ll go from the top.

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3

Thanks Liam! That makes more sense now that you mention it.

Thanks,
Mark

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4

M6 is the usual size, and agree w/ @LiamN that installing from underneath is the hot ticket.

We sell them:

and have this note on dimensions:

  • Length: 13mm (~1/2")
  • Maximum Hole Size: 9mm (0.354", Letter T Drill)
5

Thanks William and Liam. I ran a 11/32" drill and counter sinked the hole from the back side to accommodate the flange below the surface. They are pretty tight in the hole and that is good. BTW, I am using these holes to accommodate a fence.

Thanks,
Mark

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6

Looks like you have an hybrid table. If there is anything under that you need to make sure the bolts you use are long enough to the bottom of the threaded inserts but not stick out below the threaded insert. The reason is if the bolt is longer than the bottom of threaded insert the bolt when tightened tends to make the spoilboard uneven. Plus the bolts might not tighten up enough if bottomed out to let your material come loose. As you trim down your spoiboard recheck that your bolts do not bottom out on something below the threaded insert bottom. You might need to get new shorter bolts and/or grind off some of the bolt. If you grind off a bolt then insert the proper size die so you can cut the threads back at the bottom to avoid them starting hard in the inserts and possibly cross threading the inserts.

When you insert threaded inserts of any type it is a good idea to champher the hole to get the threaded insert to start straight. When you try to screw a threaded insert in without champhering the hole you can start the insert crooked. Plus as yours have a slight taper at the head you had to do that anyway.

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7

Thanks for the pointers Guy. My screws are just long enough to have 2-3 threads in the insert and only tight enough to hold the fence solid…

8

On those of mine that don’t have a through hole I blow them out with compressed air before putting the bolt in just to check I’m not building up a wad of compacted sawdust in the bottom.