From Thomas Jefferson Encyclopedia
In 1794 Jefferson added a nailmaking operation to his blacksmith shop on Mulberry Row at Monticello. He hoped it would provide a source of cash income while he restored the depleted soil of his farms. Nail rod was shipped from Philadelphia and hammered into nails ranging in size from six-pennies to twenty-pennies. In 1796 Jefferson acquired a nail cutting machine, which made four-penny brads from hoop iron.
In his Farm Book Jefferson wrote: "Children till 10. years old to serve as nurses. From 10. to 16. the boys make nails, the girls spin. At 16. go into the ground or learn trades." Up to fourteen young male slaves, aged ten to twenty-one, worked at the forges of the nailery. From 1794 to 1796, when he was retired to Monticello, Jefferson calculated the efficiency of the nailers, each day weighing their nail rod and the nails they produced. Most of the slaves who began their working lives in the nailery became tradesmen. Moses Hern and Joe Fossett became blacksmiths; Lewis and Shepherd were carpenters; Barnaby Gillette was a cooper; James Hubbard a charcoal burner; Wormley Hughes a gardener; and Burwell Colbert was Monticello butler as well as a painter and glazier.
The nailery was quite profitable in its early years, supplying nails throughout Albemarle and Augusta counties. Management problems and the competition of cheaper imported nails later made it an only intermittent source of income. No orders for nail-rod were recorded after 1823.
Primary Source References
1791 May 27. (Jefferson's Travel Diary). "Waterford [NY]. Saw nails made by cutting them with a pr. of sheers from the end of a bar of iron, the thickness of which corresponded with the thickness of the nail, & it's breadth with the length. We saw 120. cut off in a minute, & 24 headed in a minute, which would amount to 20. a minute cut off and headed, but they make habitually about 4000. a day. The iron formed into bars costs about 50 pr. cent more than nail rod. The sheers cost 9. dollars. The bit is sometimes welded to the sheers, sometimes fixed on with screws so as to be taken off to be ground. They are made at Lebanon in N. York. The lever vice for heading is very simple."
1795 March 11. (Jefferson to Henry Remsen). "Indeed I would be glad to know the cost of the cutting & heading machines, & of the right to use them if under a patent."
1795 April 2. (Jefferson to Henry Remsen). "I have recollected that at either Troy or some other little town up the Hudson I saw a man cutting the 4d. nails and that the implements were of very small cost, and not under a patent, and I suppose this to be the method of cutting to which your letter refers. I therefore have concluded to ask the favor of you to send me immediately all the implements (if they be few & of little cost as I suppose)..."
1795 April 29. (Jefferson to Jean Nicolas Demeunier.) "I now employ a dozen little boys from 10. to 16. years of age, overlooking all the details of their business myself and drawing from it a profit on which I can get along till I can put my farms into a course of yielding profit. My new trade of nail-making is to me in this country what an additional title of nobility or the ensigns of a new order are in Europe." 
1795 June 18. (Jefferson to Henry Remsen). "...I observed your expected Mr. Burral to be shortly in New York & to give you further information on the subject of the machine for cutting nails. Without waiting for the further information, (as I am much pressed for nails) I am disposed to accept his offer of making a machine for 40. Dollars. The difference of a few Dollars is of no account in adopting a thing which is to be of long continuance. So that unless you shall have received information which in your own judgment renders some other more eligible, I will pray you to get on of Mr. Burral's very complete, & to forward it to Colo. Gamble in Richmond, with 500. lb. of the proper iron for cutting 4 pennies, and a few (say 150.) 4 pennies, 6 pennies & 8 pennies, of the cut nails, by way of sample."
1795 July 10. (Jefferson to James Lyle). "A nailery which I have established with my own negro boys now provides completely for the maintenance of my family, as we make from 8. to 10,000 nails a day and it is on the increase." 
1795 November 14. (Jefferson to Thomas Mann Randolph). "Biby's boats are arrived & have not brought my 4d. nail machine nor hoop iron. Gamble & Temple write me it was in the hands of a Mr. Ball, and sent somewhere up, perhaps to Westham. Will you be so good as to have it sought for, or it may lie months in some out of the way place, or perhaps never be found. It had better come in some waggon to Colo. Bell, if it can be handily got aboard one, as there is no Milton boat down & the article is important to be guarded against miscarriage."
1796 January 11. (Jefferson to Thomas Mann Randolph). "I am in hopes my curring machine, hoop iron & rope will be up soon. If this should find you in Richmond perhaps you can aid in getting them off, as also 3. or 4. tons of nail rod lodged for me at Gamble & Temple's."
1796 February 7. (Jefferson to Thomas Mann Randolph). "Faris is gone down & promised me to call on Britton again for the machine. The difficulty has been to find him at home. Should he fail this time it would be well to have the machine carried back to Colo. Gamble, from whence it can be got at any time. My nailrod is arrived safe. The hoop iron I presume is with the cutting machine as they came together."
1796 February 22. (Jefferson to Archibald Stuart). "I have just received my cutting machine, & iron for 4. pennies, which I shall shortly begin to cut."
1798 February 12. (James Madison to Jefferson). "I returned from Albemarle on Monday last, where I consulted with your Nailer on the subject of the Sprigs & lathing nails not included in the parcels prepared for me. I found that the cutting machine has never been reestablished, & I did not request this slight kind of nails should be made in the common way. If you mean however that the machine shall be set up again, or it be a part of your plan to make such nails in the common way..."
1798 February 22. (Jefferson to James Madison). "Tho' it is my intention & orders I left were, that the cutting machine should be repaired, yet I think it would be adviseable [sic] for you to depend on it, as to your sprigs & lathing nails if you want them before my return...Immediately on my return my own wants will oblige me to recommence cutting."
1801 May 15. (Benjamin Perkins Washington to Jefferson). "The Letter Inclosed Came to me with a Request to furnish you with a Drawing of a Machine for Cutting Nails for which My Brother Obtained a Pattent. The Drawing Shall be Handed to you & any Explanations Neciry [sic] given by Wednesday Next..."
1801 March 24. (Jefferson to Thomas Perkins). "My nailers are employed in hammering nails, except one cutter for four pennies only, our neighborhood requiring no other cut nail, so that is it but a small business with me...I am not certain that I perfectly understand the manner of making the vice for holding and pushing up the hoop iron; tho I have some idea of it; and you do not mention whether you cut your hoop cold or warm. I cut it warm, in which case the frequent changes necessary would waste time."
'1806 October. (Jefferson to Edmund Bacon). "Those who work in the nailery are Moses, Wormley, Jame Hubbard, Barnaby, Isbel's Davy, Bedford John, Bedford Davy, Phill Hubbard, Bartlet, and Lewis. They are sufficient for 2 fires, five at a fire."
1806. "Jim makes 15 pounds. 20d Nails
Barnaby makes 10 pounds, 10d do.
Wagner Davy makes 10 pds. 10d do.
Bedford John makes 8 pounds. 8d do.
Bedford Davy makes 6 pounds. 6d do.
Bartlet makes 6 pounds. 6d do.
4 Boys makes 8 pounds. 6d
[total] 63 pounds nails"
1812 June 22. (Charles Artzt to Jefferson). "The object upon which my choice fell, was nailcutting machinery, for, although these machines, used in the vicinity of Boston, were almost in every respect perfect uncorrigible, yet there had one important improvement often been attempted and never been attained, viz. to have these machines selffeeding. It seemed therefore the most convenient..to undertake the invention of a selffeeding nail machine, as after four months working, had the satisfaction, to present to the public a complete selffeeding nail machine, made on a small scale, yet all from metal, and only fit to cut nails from hoops of tine, or lead or copper..."
- ↑ Please note that this list should not be considered comprehensive.
- ↑ PTJ, 20:454.
- ↑ Ibid, 28:305.
- ↑ Ibid, 28:323.
- ↑ Ibid, 28:341.
- ↑ Ibid, 28:388.
- ↑ Ibid, 28:405-406.
- ↑ Ibid, 28:527.
- ↑ Ibid, 28:580.
- ↑ Ibid, 28:608.
- ↑ Ibid, 28:618.
- ↑ 28:616.
- ↑ Ibid, 30:95-96.
- ↑ Ibid, 30:127.
- ↑ Massachusetts Historical Society. http://www.masshist.org/findingaids/doc.cfm?fa=fa0031
- ↑ PTJ, 33:434-435.
- ↑ Bear, Jefferson at Monticello, 53.
- ↑ Overseer's account of daily task of nailers.
- ↑ Library of Congress. http://memory.loc.gov/cgi-bin/ampage?collId=mtj1&fileName=mtj1page046.db&recNum=123