Report on the manufacture of saddletrees, Rock Island Arsenal, July 31, 1897
ANNUAL REPORTS OF THE WAR DEPARTMENT FOR THE FISCAL YEAR ENDED JUNE 30, 1897
REPORT OF THE CHIEF OF ORDNANCE
WASHINGTON: GOVERNMENT PRINTING OFFICE 1897
excerpt from page 8
EQUIPMENTS
From 1865 until about a year ago our saddles have been made from saddletrees which were left on hand at the close of the war. This supply being exhausted and it being necessary to procure a new supply, the question was raised as to whether these trees should be manufactured at the arsenal or whether they should be procured by contract, as has been done heretofore. The trees procured by contract were not of as good quality as is desirable, but their serious defect was that being made by hand they did not conform in shape and dimensions to the rigidly exact requirements for a tree that will perfectly fit a horse’s back. This subject received careful attention about twenty years ago and led to the construction of exact metal forms to be applied to the old trees to determine their variations from specified dimensions. The trees being on hand, to save the loss of throwing them away, greater variations from specified dimensions were allowed than would have been permitted in manufacturing new trees. Even with these greater variations it was found that as high as 45 per cent of the trees on hand furnished by some contractors during the war had to be rejected. Others conform more closely to requirements, but in all cases a large percentage had to be rejected.
It was my opinion at that time that these trees might be made with machinery, somewhat upon the same methods that are pursued in making gunstocks, lasts, etc. If so made it was thought that the form and dimensions of the trees might conform exactly to specified dimension, without any variations whatever, or rather that this exact conformity would necessarily result from the proposed method. It was also thought the devising of this machinery would better be undertaken in the arsenal shops, and if successful it would not only give the very desirable conformity to dimensions, but result in the construction of stronger and better trees in all respects. This work was undertaken and has been brought to a successful conclusion, and it is thought it not only results in better trees of accurate dimensions, but that the cost of the tree has also been somewhat reduced. A detailed report on the subject, made by Lieutenant Horney, is printed as one of the appendices to this report.
appendix beginning from page 63
plates at bottom of page
APPENDIX 4
REPORT ON THE MANUFACTURE OF SADDLETREES
(3 plates)
ROCK ISLAND ARSENAL,
Rock Is1and, Ill., July 31, 1897.
SIR: I have the honor to submit report as follows concerning the manufacture of saddletrees at this arsenal, of which work I was placed in charge in March, 1896, by the oral orders of Co. A.R. Buffington, Ordnance Department, then commanding the arsenal. In the manufacture of saddles at this arsenal old saddletrees have been used exclusively, until recently. The old trees that have been used were handmade, and varied considerably in size and shape, and it became necessary to prepare maximum and minimum gauges for each size of tree, in order to determine which should be used and which condemned.
In March, 1896, I made an examination of the old saddletrees then on hand, with a view of determining how long the supply would last. As it was evident that the manufacture of new trees would have to be taken in hand at an early date, a careful inspection of old condemned trees was made, to determine, if possible, what were the weakest points in their construction, so that in the new trees these defects might be remedied. It was found that a great number of old trees were broken through the pommel, while others were rendered unfit for use by excessive warpage of the side bars. These were almost the only causes for the rejection of saddletrees. To remedy these defects I devised a form of pommel arc and cantle arc which, it is believed, entirely overcomes the difficulties mentioned.
On March 30, 1896, pursuant to oral instructions from the commanding officer, I made a written report of the matter and submitted a model saddletree fitted with these new arcs.
In preparing this tree, the hasps or straps with which the stirrup loops were secured to the side bars where made with half-round ends instead of square ends as heretofore. This was done so that the mortise into which these hasps fit can be cut out on a molding machine.
The shape of the tree is that approved and recommended by the cavalry equipment board of 1874, as modified by the cavalry equipment board of 1884. It follows the drawings made at this arsenal April 26, 1886.
This model was approved by the Chief of Ordnance April 4, 1896, and the commanding officer of this arsenal was directed to prepare fifty saddles of the new model for trial in service.
The turning of the side bars, due to their very irregular shape, requires a very strong, rigid machine, and as it was found that such a machine as was needed would be very expensive to buy, a form of eccentric lathe adapted to this work was devised and manufactured at this arsenal.
On account of the press of work in the machine shop considerable time elapsed before this machine was completed. The fifty saddles for trial were completed on February 18, 1897, and are now in use.
The tree consists of 2 side bars, 1 pommel, 1 cantle, 1 pommel arc, 1 cantle arc, 2 stirrup loops, 2 stirrup-loop hasps, 18 rivets, and 8 screws.
It was necessary to do some experimenting to determine the best methods for manufacturing these trees. The following is the method fully worked out:
The side bars are made of basswood, on account of its lightness and the difficulty with which it splits. They are first roughly sawed to shape, as shown in fig. 1, pl I, and then turned out on the eccentric turning lathe above referred to, which turns two pieces at once. The side bar as it comes from the lathe is shown in figs. 2 and 3, Pl. I.
After being turned the side bars are fitted to cast-iron forms and smoothed on a sandpapering machine. The mortises for the stirrup-loop hasps are then cut on a molding machine, the side bars being held in a jig to secure uniformity in the position of these mortises. The finished side bar is Shown in fig. 4, Pl. 1.
The pommel is made of ash in two pieces, fitted and glued together with a tongue and groove joint, as shown in figs. 10 and 11, Pl. I. The tongue is made with the grain running at right angles to the line of the joint. The pommel is first sawed roughly to shape on a band saw, as shown by dotted line, fig. 10, and then brought to proper dimensions on molding or shaping machine. The faces which come in contact with the side bars are brought to the proper bevel on a disk sandpapering machine. The mortise is first bored and then cut out under a boring and mortising machine, the pommel being clamped to a jig, so that all are cut exactly alike. The finished pommel is shown in figs. 12 and 13, Pl. 1.
The cantle is made of ash in two pieces, which are fitted together as in the case of the pommel. After being sawed roughly to shape on a band saw it is turned to its finished dimensions on a lathe. The surfaces which come in contact with the side bars are brought to proper bevel on a disk sandpapering machine, and the mortises are cut out as described for the pommel. Figs. 5 to 9, Pl. 1, illustrate the process of manufacture of the cantle, figs. 8 and 9 showing its finished form.
The pommel and cantle are each secured to the side bars with No. 12 iron screws, two 1 1/2″ inches long and two 1 3/4″ inches long.
In the old saddles this was the only connection between pommel and cantle and side bars, but in those now manufactured they are farther connected through the new form of pommel and cantle arcs above referred to.
The pommel arcs are made by first punching out the blanks from soft sheet steel of No. l6 gauge (Stubbs). The blanks are heated and pressed to shape between dies on a bulldozer, and the edges are then ground off to a bevel, so that when the tree is covered there will be no sharp edge to cut the rawhide.
The pommel arc is shaped to the angle between the side bars and the front of the pommel, and is secured to the plane surfaces of the side bars and to the front face of the pommel by No.8 iron rivets–two in pommel and two in each side bar.
The cantle arcs are made of the same material and in the same way as the pommel arcs. They are shaped to fit the curved surface of the back of the cantle and the plane surfaces of the side bars in rear of cantle.
The method of fastening is exactly the same as in case of pommel arc. The forms of the pommel and cantle arcs are shown on Pl. II, figs. 1 and 2, and their position on the saddletree is shown in fig. 3, same plate.
The stirrup loops are secured to the side bars by means of straps, which are riveted by three No. 8 rivets, arranged in zigzag order, so that no two shall be in line with the grain of the wood. The straps are of low steel No. 18 (Stubbs’s gauge).
The different parts of the saddletree are assembled on cast-iron forms, so that they are very uniform in size and shape.
The tree, after being painted with white lead, is covered and trimmed in the same manner as were the old trees heretofore used.
The following is a bill of material for one saddletree: Two pieces bass-wood 2 1/2 by 7 by 26 inches; 2 pieces ash l 1/2 by 3 by 8 1/2 inches; 2 pieces ash 1 1/2 by 5 by 8 1/2 inches; 1 piece 2 1/2 by 14 1/2 by 0.065 inch, 1 piece 2 1/2 by 12 1/4 by 0.065 inch, 1 piece 1 5/16 by 9 3/4 by 0.049 inch best quality low decarbonized sheet steel; 1 piece best wrought. iron wire (annealed) (0.284 inch diameter by 10 1/2 inches long.
NOTE.-In ordering lumber about 6 per cent of wastage should be allowed for.
Very respectfully, your obedient servant,
ODUS C. HORNEY,
Lieutenant, Ordnance Department, U. S. A.
The COMMANDING OFFICER, ROCK ISLAND ARSENAL, ILL.
(9981-Enc. 3)
ORD 97—5
