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RFQ for grinding/alteration of T-nuts

woodguy2

Plastic
Joined
May 31, 2019
I'm looking for a quote for cutting flats on an existing round base Mcmaster T-nut :https://www.mcmaster.com/90596A250/ They're 1.25" diameter.
I need them cut so that they'll slide, but not rotate, in a 1" wide groove. So target width of .96" with a .03" tolerance. Please quote for 200 and 500 pieces. I'll purchase stock and ship to you.
 

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Scottl

Diamond
Joined
Nov 3, 2013
Location
Eastern Massachusetts, USA
First off, those are weld nuts, not T nuts. Not sure how flat they are so depending on your slot they may bind.

Have you already tried modifying a few with a belt sander or whatever to see how they work?
 

sfriedberg

Diamond
Joined
Oct 14, 2010
Location
Oregon, USA
If I had "a few dozen", I'd make a quick holding/sizing jig and run them in batches on a stationary belt/disk sander. If you put "stop legs" on the jig that meet the platen and used a narrow belt that fits between the jig legs, even unskilled/inexperienced labor could grind them to size. At many hundred pieces, I'd make a serial gang fixture for the horizontal mill, and straddle cut about 15 parts in one pass. Could do something similar with special vice jaws maybe 4 at a time on a turret mill, but you can't just clamp on the barrel of multiple parts; Needs accomodation for variations in blank size.
One comment: 3/64" flange thickness is going to deform fairly easily under clamping pressure. They might not bind going into the slot, but once you use them, they may be rather more difficult to reposition or get out of the slot.
 

woodguy2

Plastic
Joined
May 31, 2019
Thanks for these comments and suggestions. I'd been thinking more along the lines of nippers or angle grinders, but no real experience needing to do something like this in some quantity. I was hoping a machinist might have a quick way of doing these easily with the right tool. I realize the quantity I'm asking for isn't real exciting, but if the product catches on could be a lot more.

Yes, I have made several prototypes, and they work well. They'll be used for securing an adjustable angle fence on table saw cross cut sleds, so not much clamping force is required. The fence can be removed and replaced at an alternative location, and I use magnets to "park" a set of nuts in a "home" position, and their large surface area allows for using larger more powerful magnets that hold just right. They ride on a baltic birch plywood face. The sides that face the clamp surface of these weld nuts (thanks for the correction), are pretty flat and smooth with some shallow radial striations. I'm a woodworker, and do own an edge sander that I think I could fixture as sfriedberg suggests, though it runs faster than it probably should for steel. What type abrasive and grit should I use for a belt for this job?
 

BT Fabrication

Stainless
Joined
Nov 3, 2019
Location
Ontario Canada
this is a perfect punch press type of job. perfect for mine or anyone's ironworker, but the die to do it will be cost prohibitive in a couple grand range for any production qty. easy enough job that it would take almost no time to punch out. if designed correctly.
 

sfriedberg

Diamond
Joined
Oct 14, 2010
Location
Oregon, USA
What type abrasive and grit should I use for a belt for this job
I have a 6x48 belt sander with a catalog belt speed of 2500 feet/minute. I can burn steel, but seldom do. However, I don't think belt speed going to be very critical in this application. If you can't slow down your edge sander, just use a lighter and intermittent touch. The flanges will more or less evaporate in contact with the belt. Use a good quality 60 or 80 grit coated belt. I am currently running 3M 947 Cubitron and expect lots of other things will be equally appropriate.

[Added in edit] Avoid contaminating your woodwork, especially if you do transparent stains or varnishes. Dedicate a belt to the metal work.
 

majohnson

Cast Iron
Joined
Jan 3, 2013
Location
Erie, CO
You could just mill one side flip it on a parellel to remove the balance. Unless you want a ground finish on the edges. One issue on a belt sander is going to keep the sides parallel. On your sizing is that .96 plus or minus .030”, or are you thinking .003”.
 

woodguy2

Plastic
Joined
May 31, 2019
"On your sizing is that .96 plus or minus .030”, or are you thinking .003”." It really is .03"--no need for precision here.

I'm looking forward to trying a few dozen with a belt sander fixture, and if I find it too laborious, I've got a couple reasonable quotes from people here.

This forum is a great resource.
 








 
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