Salopian this type of problem was solved way back in the past well before the lathe was a twinkle in Mr Maudsley's eye, at a cost of a few pounds/dollars because you do not need to throw money at this problem. you will require a three inch square piece of timber about four foot long. Eight inches of steel tubing with a half to three quarters hole, two pieces of timber about a foot long three inches wide and one to one and a half inches thick. One six by three quarter inch steel bolt and finally one carpenters six inch clamp failing that two three inch no 10 wood screws. finally a one six inch nail
The how! What we are going to make is a drilling gig of the simplest type. from the three inch square wood cut two six inch pieces at least one end of each piece must be cut square to all sides, if you do not do a good cutting job adjust with a file rasp or abrasive paper and check with a square. Put some effort in to one of the pieces because this is going to be the head stock of your jig and the hole you will put through must be parallel to this. Taking your head stock piece drill a hole two inches from the top in the center to accommodate your length of tubing, it is very important this hole is at right angles to the base. To keep the tube from sliding in the hole apply some Epoxy Adhesive. Now we will fix this piece with the tube to one end of your long length of timber using Epoxy Adhesive because this also fills op any slight gaps making a firm fixing, make sure the tube is facing along the length of the timber. When the Epoxy has set drill a tight clearance hole through the bottom piece of timber into the head stock piece to add rigidity. The movable tail stock end is far simpler to make, firstly glue and screw your three inch block to one end of your three by one to one and a half inch timber. Your other piece of three by one or one and a half is fitted to one side of the bottom piece of three inch square timber standing proud by an inch to act as a fence to keep your tail stock parallel to the head stock. finally push tour tail stock up yo the tube now drill a hole through the tail stock to accommodate your bolt having first ground a tapered center then glue in place making sure this lines up well with your guide tube.
To use the gig clamp the bottom section of the gig in a vice decide on the drill size you want to use and make a couple of drill bushes to allow the drill to run concentric in the tube (I have used strips of a tin can to make temporary bushes well greased) center punch your stock or blank at each end in the correct places, now for the tube end you drill a shallow hole to accommodate the end of the tube tightly. now mount your stock or blank between the guide tube a d the tail stock center clamping the tail stock to the base using a carpenters clamp or just screws. I will say it is a two person job one to cope with the long drill and another to hold the stock or blank to stop it rotating.
This jig for drilling deep holes was not my Idea, they had one of these in the collage I attended for drilling long holes in wooden table lamps and floor standing lamps up to six foot long, though it was built from hardwood and using more steel parts. The version I described was the type I used before I had a lathe and it lasted many years of use
Ernie
