E-Z Lok 400-428 Threaded Insert, Brass, Knife Thread, 1/4"-28 Internal Threads, 0.500" Length (Pack of 25)

I have used both the 1/4-20 and the m8 inserts on softwoods, plywood, and hardwoods. I found early on that the recommended hole size does not always work. The recommended size works fine for softwood but not always for hardwood. Do a few trials before you commit to installing them. Also, I have found that I cannot put these in with a screwdriver, the ends of the inserts chip and shatter. I have had the same problem with EZ-Loc's custom insertion tool. Their tool works for softwood, but nothing very hard. I use a tool made from a bolt, a couple of nuts, and a washer mounted in my drill press to put these things in. Almost always works without stalling the drill, but not always.Recently I gave up trying to use the m8 inserts in some 40+ year old oak I reclaimed from some criminally mistreated furniture. The m8 will only go into a 14mm hole in such a hardwood. I tested 1/2, 33/64 (the recommended size hole), 13mm, and 14mm. The inserts will pass clean through a 15mm hole... I found the only hole I could get the insert into was the 14mm hole. At that size the threads are barely engaged with the wood and the insert+hole is unsightly.I have also found that they will split hardwood if it is not wide enough. These will delaminate plywood unless you have a solid backing for the wood. At this point I wish I could find a tap designed to works with the outside threads of this product. That would be very handy for using these with hardwoods.Like I said, do some testing before using these. You might want to test before you include them in a project plan.

I was skeptical at first hearing about what size hole to drill and inserts not going in. One reviewer said to use a 14mm Forstner bit and he was right on. I was drilling into a maple glue up table top so it was the worst of situations for the inserts, super hard wood. The 14 mm bit worked perfectly and the inserts screwed in without flaw. I also bought the drill adapter specifically for the inserts which was worth every bit of 10 bucks, it made for very secure turning in the inserts. Be sure to put your drill on low speed and start very slow, making sure you are as plum straight as you can be with a handheld drill. Low and slow is key for these inserts, don't try to spin them in on high. I only screwed 1 out of 12 up and that's because I started crooked and though i could straighten as i went but no, you should immediately back out and start again. I barely got the insert out because the adapter bit is designed to put them in and not so much to remove them, it tore up the top edge of the insert but did get it out. Again, this was only the case because it put it in crooked to begin with, I was easily able to remove the ones that were put in straight. All in all this product worked perfectly as well as the optional adapter which is a must have. Also worth noting, i bought the M8 bolt size insert, the adapter bit fits down into the 14mm pocket which allows you to turn the insert flush or even below the surface if necessary.

Ordered this for 1/4-20 furniture levelers. As others have suggested, I drilled a 1/32" oversized hole (in end grain ash). I lubricated the holes with a thinned out waxy product (but any lube would do). I used the jam nut method on a tool that I repurposed for the task. I was able to rap the end of the tool as one might a nail set to get the insert started reasonably straight and then just carefully applied pressure as I twisted the insert into the hole. I ended up countersinking the insert a bit and when I backed the tool out, it came away nicely. Even though I had an issue getting the first insert straight into the hole, by using the nail set method I was able to re-drive it in straight. The other three went in with no issues at all. Pleased with the product. It worked out well.

Once these are inserted into the wood properly, they are both sturdy and very attractive. These are great for any wood project that might need to be taken apart occasionally or requires a more refined look. The reason is that if you have to insert and then remove a wood screw more than a few times, the screw hole will get chewed up and not hold the screw tightly anymore. These inserts allow you to use a machine screw instead that can be removed and inserted any number of times without weakening the joint.Ok. Now some advice i wish i had before i started working with these. I used the E-Z Lok inserts for hard wood (part 400-006 with 6-32 internal thread size). E-Z Lok recommends the hole to be drilled for these should be 1/4". At this diameter, there was no way i could get the insert below the surface of the wood even with lubrication. I used a properly-sized screw driver but it required so much force that a good size shard of brass cracked of the edge when i attempted to put in the last few turns. I wound up drilling a 5\16" hole which worked MUCH better. The insert did not feel loose at all and if this is at all a concern for some, apply a small amount of wood glue on the outer threads before inserting it. Also, even though a flat head screw driver will work, the groove for turning it is quite wide so this is not ideal. E-Z Lok makes a special bit for turning the inserts which would probably make a big difference, but I personally dislike having to carry such a specific tool.Secondly, the inserts have an amazing ability to start going in crooked even if they started out straight on the first few turns. On my project I drilled a through hole in the wood so i could access the bottom side of the insert while inserting it. The reason this helped is because i could partly inset a 6-32 screw from the back and use it as a handle to straighten the insert if it began to get crooked while screwing it in. Then i simply covered the hole with a little wooden plug and the result looked and worked great. This is unfortunately not an option in the case where you can only drill a blind hole, which i would assume is most of the time.In the end they worked out quite well and I hope my advice saves you some frustration.

estas piezas estan fabricadas con my buena calidad y un empaque adecuado, llegaron en muy buen tiempo y todo sin problemas lo recomiendo absolutamente