Special threaded tubing needed

Hey Jim, If your item is not critical, you could easily make it by using 1/2" all thread material, cut to length, drilled and tapped 1/4-20. You have the option of picking the actual size you'd prefer for the OD, you needn't stick with 1/2". In quantity, a tapping head would be mandatory A lathe would certainly be helpful, but a saw and drill press could produce the part. A belt sander to deburr the saw cuts wouldn't hurt, either. All depends on your ability to come up with a useable setup. Do you have any equipment to aid you in making the parts? How many do you need? Do you want to share with us how you intend to use the part? Could help in making decisions.

Harold

You may be able to find a threaded insert of the 'time-sert' or 'keensert' type to do exactly what you want.

These are OD/ID thread pieces which are designed to repair stripped-out threads. So if one happened to have, say, a stripped 1/4-20 hole in a casting, one could drill it up to 3/8 or so (the exact size of thread will of course be listed by the insert manufacturer, and they will supply a special tap for this) and then the insert is wound into the new, larger hole, and locked in place.

Do a web search on 'timesert' and see what you find.

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

Id like to thank everyone who offered help. Between your advice and good ol trial and error, I got what I needed! I ended up drilling and tapping a

3/8-16 bolt on the inside to 1/4-20. I then simply cut the head of the bolt off and voila, one "tube" threaded in and out. Now then someone asked what this was all about. Well, Im actually a woodworker/cabinetmaker by trade and I have a plunge router mounted upside down in a table. Bit height adjustment has always been a royal pain, reaching and groping under the table to reach the knob that raises and lowers the bit. There are a couple of products on the market that remedy this problem and as you could probably guess they are ridiculously expensive. So I decided to develop my own product to solve my own needs and perhaps maybe even put on the market myself. I have a total of $7.00 in parts to make my router raiser and the cheapest one available commercially is $89! Another one sells only with a special table insert and starts at $149. Totally unacceptable I thought to myself and now I have a working model with which to test on my router tomorrow. I cant wait to see how it works, I think its going to be great. And for only $7.00 !!

Jim

When I was working in industry, we had a quick and dirty rule of thumb for estimating selling price of a design. This was only used for preliminary design discussions but it always surprised me with how well it worked when we compared it with more thorough estimates. The rule is: Take the cost of the components that appear on the circuit diagram and multiply by five. This is to take care of hardware, labour, packaging, ... Applying this rule to your device would come up with a manufacturer's selling price of $35 so it would probably be in the ballpark of $50 to $70 retail. Those guys may not be all that far off! If you do go to market, don't price so low that you can't make a reasonable profit. (I DON'T mean Gatesian reasonable!)

Ted

Ted, that same estimate value is used in our operation.

RJ